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Folks,

B.R. 901/43, Handbook On The Use Of Radar For Gunnery Purposes Visual/Radar Target Indication, 1945, describes the radar target designation system of the Royal Navy in WW II.

In this online version of the manual we have attempted to keep the flavor of the original layout while taking advantage of the Web's universal accessibility. Different browsers and fonts will cause the text to move, but the text will remain roughly where it is in the original manual. We have not attempted to correct any errors found in the original document. However, this text was captured by optical character recognition and then encoded for the Web which has added new errors we wish to correct.

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Copy No. 9
C.B. 4112 8 45 B.R. 1634 8
HANDBOOK
ON THE
USE OF RADAR FOR
GUNNERY PURPOSES
VISUAL/RADAR
TARGET INDICATION
1945



CONFIDENTIAL

This book is the property of H.M. Government.

It is intended for the use of the Officers generally and may, in certain cases, be communicated to persons in H.M. Service below the rank of Commissioned Officer who may require to be acquainted with its contents in the course of their duties. The Officers exercising this power will be held responsible that such information is parted with due caution and reserve.

 

CONFIDENTIAL

Attention is called to the penalties attaching to any infraction of the Official Secrets Acts.

C.B. 4112 B.R. 1634(8)(45)

HANDBOOK
ON THE
USE OF RADAR FOR
GUNNER PURPOSES

VISUAL/RADAR
TARGET INDICATION


1945

ADMIRALTY, S.W. 1
GUNNERY BRANCH

 

Illegible revision history.
 

iii
 

ADMIRALTY, S.W.1.
17th October, 1945.

G.05997/45.

C.B. 4112(8)(45)-Handbook on the Use of Radar for Gunnery Purposes, Visual/Radar Target Indication, 1945, having been approved by My Lords Commissioners of the Admiralty, is promulgated for information and guidance.

This book should be inserted in C.B.4112 (G.B. and I.)-Guardbook and Index for Handbook on the Use of Radar for Gunnery Purposes.

C.B. 4112(8)-Handbook on the Use of Radar for Gunnery Purposes, Visual/Radar Target Indication, 1944-is hereby superseded and all copies should be destroyed in accordance with Article 42, B.R. U.2.D. (1945).

By Command of Their Lordships,
H.V. Markham signature.

To Flag Officers and Commanding
Officers of H.M. Ships concerned.

(C50071) B2

 

iv
 

CONTENTS

Foreword Paragraph
CHAPTER I
Introduction
General Objects of the T.I.U. How the Objects are Attained Where the T.I.U. is Fitted Limitations Accuracy Performance I.F.F. Communications Other Publications 1-29
Page iv, CONTENTS, Introduction. Delete and substitute:
General-Objects of the T.I.U.-How the Objects are Attained-Where the T.I.U. is Fitted-Limitations-Accuracy -Performance - I.F.F. -Communications -Other Publications-Armament Broadcast System
1-39
CHAPTER II
Description of Radar W.C., Types 29311, and W.S., Type 276
Equipment in the Office-The Aerial Arrays-The Aerial Control Table-Control Table Bearing Indicator - Interrogator Aerial Follow-up Switch - Lining-up Details Types 293/M-Type 242
41-52
CHAPTER III
Description of T.I.U Marks IIA and IIB
The T.P.I.-Working Controls-The T.I.U. Box-Principle of Operation of the T.I.U. Box-Description of the T.I.U. Box-Sector Selector Switch-Interrogator Aerial Transmitter Drive-The Projector Unit and Optical System-Ranging Outfit R.T.B.-R.T.U. 53-Indicator Outfit J.H.I. (I.F.F. Panel 43)-Close Range Armament
61-108
CHAPTER IV
Procedure for Target Indication
PART I-General.
Functions of the A.I.C.-Interpretation of T.P.I. "Pictures"-Drill and Procedure
111-117
PART II-Battleships, Cruisers, Aircraft Carriers-A.A. Target Indication.
Selection of Target Indicating Position-Target Indication by the A.D.O.-Target Indication by the P.C.O.-Target Indication by the T.I.O.-Target Indication for Close Range Weapons by T.I.O.
118-134
PART III-Battleships, Cruisers, Aircraft Carriers-Surface Target Indication.
Target Selection-Surface Target Indication by the T.I.O.-Separate Main Armament Target Indication in Battleships and Cruisers-Duties of Gunnery Liaison Officer (G.L.O.)-Use of Starshell-Positions for Target Indication Switches
135-147
PART IV-Destroyers-A.A. and Surface Target Indication.
Target Indication Arrangements-Searchlight Training-Searchlight Elevation-Change-over Switches-Switching Drill
148-154
PART V-Setting-up Details.
Initial Setting up of the T.P.I.-Centring the Trace-Adjusting the Pre-set Controls Setting up the Trace-Lining-up the T.P.I.
155-162
CHAPTER V
Adjustments and Tests
Erection Adjustments and Tests-Lining-up and Checking when Closing up-Checking Connection of Aerial Repeater Motor-Checking Connection of Compass Repeater Motor-Lining-up of the T.I.U.-Workshop Lining up-Installation Lining-up on board and Adjustment of the Optical System-Magslip Alignment-Sectoring Switch Alignment-Sectoring Switch Adjustment-Hunter Adjustment-Procedure for Dismantling a T.I.U.
171-198
APPENDICES Page
Appendix-I-Functions and Positions of Target Indication Change-over Switches ("Battle" Class Destroyers; not applicable to Leaders) 23
Appendix H-Coverage Diagrams for A.U.J., A.U.R., A.Q.R.  
APPENDICES. Delete and substitute:-
Appendix I.-Functions and Positions of Target Indication Change-over Switches ("Battle" Class Destroyers; not applicable to Leaders)
23
Appendix II.-Coverage Diagrams for A.U.J., A.U.R., A.Q.R. 23A
Appendix III.-T.I.U. Mark II. Modifications to Existing Sights and Directors 23B
Appendix IV.-Capital Ships, Cruisers, A/C Carriers, Monitors-Armament Broadcast System. Requirements of Microphones, Speakers, Change-over Switches, Amplifiers, and other communications affected. 23C-D
Appendix V.-In Destroyers and Small Ships. Action Information Intercommunication System. Armament Broadcast System. Action Intercommunication System. Radar Reporting Line. Requirements of Microphones and Speakers 23E-F
Appendix VI.-T.I.U. Transmissions 23G
(G. 06692/47.-C.A. F.O. P.84/47.)  
PHOTOGRAPHS
1. Frontispiece:-Target Indication Unit, Mark IIB facing 1
2. View from left-hand side of T.I.U., Mark IIB (certain covers removed) facing 8
3. View from right-hand side of T.I.U., Mark IIB (certain covers removed) facing 9
4. Target Indication Unit, Mark IIA, with Ranging Outfit R.T.B. facing 12
5. T.I.U., Mark IIB, with T.P.I. in servicing position facing 20
6. T.I.U., Mark IIB, Control Box on Transporter Trolley facing 22
7. Dials of T.I.U. facing 23
DIAGRAMS
I. Layout of Aircraft Direction Room in a Capital Ship facing 3
II. T.P.I. Picture of a Convoy Attack-First stage facing 14
III. T.P.I. Picture of a Convoy Attack-Second stage facing 14
IV. T.P.I. Picture of a Convoy Attack-Third stage facing 14
V. T.P.I. Picture of a Convoy Attack-Fourth stage facing 14
VI. T.P.I. Picture of a Convoy. Gain increased to normal searching gain facing 14
VII. T.P.I. Picture of a Convoy off the Orkneys facing 14

PLATES

1. The T.I.U. Box.
1A. Sectional Elevation of Sector Selector Unit and Interrogator Gear Box.
2. The T.I.U. Projector Unit.
3. Connections to T.I.U. and T.P.I. and Control Table.
4. Visual/Radar Target Indication. Typical communication layout for a four-cornered ship.
5. Visual/Radar Target Indication. Typical communication layout for a "Battle" class destroyer.
6. Typical Armament Broadcast System for a Cruiser.
7. The Universal Sight.
8. Method of as-assembling T.I.U., Mark II (A and B), for transportation through restricted space.
9. Circuit Diagram of T.I.U.
 

v
 

FOREWORD
TARGET INDICATION

An essential prelude to the consideration of the subject of Visual/Radar Target Indication is a thorough understanding, by officers and men concerned, of the capabilities of the various types of Radar and associated equipment. These have been specially adapted to meet the various requirements of different ships and it will thus be possible to have many combinations of Radar equipment.

A short précis of the equipment most likely to be encountered is appended and this will enable the reader to obtain a clear picture of the functions and the limitations of the equipment.

Radar Sets

W.S. Type 276.-This set has been developed from Types 271/273 and is much more powerful. It provides continuous all-round warning of surface targets and will detect low flying aircraft but not high flying aircraft. The aerial, which normally rotates continuously, is stabilised in azimuth, and has a beam which at half amplitude is roughly 6 degs. wide in the horizontal plane and 20 degs. in the vertical plane with a reliable range of 25,000 yards on aircraft. This set may be fitted to work with the T.I.U. for target indication purposes at low angles of sight.

Note.-All Type 276s in service are being converted to Type 293/M.

W.C. Types 293 and 293/M.-These sets are also developments of Types 271/3, being Type 276 with different aerial arrays. They provide continuous all-round warning of surface and aircraft targets, but the surface cover is not as good as with Type 276, this being reduced to enable the sets to detect high flying aircraft. The aerials, which normally rotate continuously, are stabilised in azimuth and have beams which at half amplitude are roughly 5 degs. wide in the horizontal plane, 65 degs. in the vertical plane for Type 293, and 45 degs. in the vertical plane for Type 293/M. They have reliable ranges on aircraft of at least 15,000 yards and 18,000 yards respectively. The normal function of these sets is target indication in conjunction with the T.I.U. and Target Position Indicator (T.P.I.). In small ships and carriers they combine T.I. and tactical warning purposes.

W.C. Type 293P.-An improved 293 set will soon be available for fitting in certain ships. This set will incorporate modifications which will give it improved performance over Type 293/M with a greater reliability.

W.S. Type 277.-This set is also a development of the Type 271/273 marque. It provides continuous all-round warning of surface and low flying aircraft targets with provision for measuring angle of sight. The aerial, which normally rotates continuously, is stabilised in azimuth and in the vertical plane, and has a narrow beam which at half amplitude is roughly 6 degs. wide in the horizontal plane and 6 degs. in the vertical plane with a maximum reliable range of 80,000 yards on aircraft. The angle of sight is measured by elevating and depressing the aerial (which has to be stopped rotating) and is shown directly on a Height Position Indicator (H.P.I.).

W.C.H. Types 980/1.-This is a F.D. (Fighter Direction) set, still under development. It is intended to give good all-round continuous warning and accurate height finding. It will only be fitted in carriers.

W.A. Types 79B and 281B/BM.-These sets are the original high-powered air warning sets converted for use with one mast only. Type 79B aerials are hand controlled and 281B/BM aerials power driven. Ranges up to 100 miles can be obtained on high flying aircraft but the low flying cover is not reliable. Types 281B/BM can work in conjunction with P.P.I.s and Skiatrons but arrangements are not normally made for it to work with T.P.I.s.

Fitting Out Policy

It is intended, when fitting out is complete, that ships should have the following Radar warning sets for the functions shown:-

TYPE OF SHIP W.A. SET. LONG
RANGE AIR WARNING
W.C. SET. TARGET
INDICATION
W.S. SET. SURFACE
WARNING
Battleship 281B or 79B 293/M 277
Carrier 281B and 79B 293/M* 277**
Cruiser 281B or 79B 293/M 272 or 273 or 277
Destroyer 291 293/M

The above schedule is only a typical layout and must on no account be taken to indicate which sets are fitted in a particular ship.

* In carriers and destroyers Types 293/M is the W.C. and W.S. set.
** W.C.H. Type 980 Will be added when available and will replace Type 277. In carriers these sets are used for F.D. purposes.

(C56071) B3

 

vi
 
Display Equipment

Plan Position Indicator.-This is more generally known as a P.P.I., and is a cathode ray tube displaying a plan picture. The trace commences at the centre of the tube and moves radially outwards, at the same time rotating in synchronism with the aerial. By placing true and relative compass rings round the tube all targets detected are shown in "plan." The range of targets shown on the P.P.I. tube can be measured off against a rotatable transparent cursor which covers the P.P.I. The cursor has three range scales marked on it in triangular fashion and by aligning the appropriate scale to a "paint," its range call be ascertained. Alternatively, calibration pips can be superimposed on the P.P.I. and ranges obtained by comparison. The P.P.I. can be used with Types 271/2/3/6/7, 291/3 and 281 and variations, as well as with other sets.

Target Position Indicator.-This is more generally known as a T.P.I. It is exactly similar in appearance to the P.P.I., but owing to the large angles of sight of some targets the presentation does not present a true plan, and the name T.P.I. is used. Similar range scales on a transparent cursor are used. When the T.P.I. is used in conjunction with the T.I.U. another type of range scale is used. This takes the form of lines of light which carry equidistant range nicks, and as the lines of light are projected on to the T.P.I. and can be rotated to align with a target, the approximate range of the target can thus be estimated from the projected range nicks while bearing is being transmitted away. Accurate ranges are transmitted from a Panel L.37 (part of Ranging Outfit R.T.B.). The T.P.I. is normally used with Types 276 or 293/M but may be switched to work with Types 277 or 291 (if fitted).

Height Position Indicator.-This is more generally known as an H.P.I., and is used to find the height of aircraft targets. Outwardly it is similar to the P.P.I. but has a different transparent cursor and no compass rings are fitted. To enable the height of an aircraft to be ascertained, the aerial array must he stopped rotating, trained on the bearing of the target and elevated through the target angle of sight which will give a "paint" on the H.P.I. Continued elevation and depression of the aerial through the target angle of sight will give a continuous "paint" and to this is aligned the transparent cursor from which the aircraft height can be directly read off. The H.P.I. can only be used with Type 277.

 

Photo of T.I.U.
Photograph 1. TARGET INDICATION UNIT, MARK IIB.

Frontispiece C56017

 

1
 

CHAPTER I
INTRODUCTION

General

Although the fleet relies upon its fighters as the first line of defence against air attack, it is inevitable that in some conditions a proportion of the attacking aircraft will penetrate the fighter defence, and reach the second and third lines of defence- the long and close range armament.

Page 1, paragraph 2. Delete and substitute:-
2. The co-ordination of the long-range A.A. defence of a fleet with its fighter defence is as essential as the co-ordination of the different groups of the A.A. armament of a ship, and calls for the closest co-operation between the Direction Officer, the Target Indication Officer and the Air Defence Officer. The Fleet Target Indication Officer is also in communication by R/T with the T.I.O.s of the Fleet or Squadron.
(G. 06692/47.-C.A.F.O. P.84/47.)

2. The coordination of the long range defence of a fleet with its fighter defence is as essential as the coordination of the different groups of the A.A. armament of a ship, and calls for the closest cooperation between the Fighter Direction Officer, the Target Indication Officer and the Air Defence Officer.

3. In aircraft carriers, battleships and cruisers, the main display plot, in addition to being the centre of the ship's fighter direction organisation, is also (together with the A.D.P.s) the nerve centre for the distribution of fire from the ship's A.A. armament, and it is at the Plot that the essential co-ordination must be achieved.

4. Due to the rapid development of Radar and the development of air warfare, it has become increasingly vital to have all possible tactical and enemy information fed to one centre, so that this information may be plotted, filtered and passed out to the various control centres and authorities who require to take action on it. This centre is known as the Action Information Centre. It consists of various offices and includes the Aircraft Plot and the Gunnery Target Indication Room.

5. The Action Information Centre can be described as the nerve centre of the ship, and from there also the L.A. and H.A. armaments of the ship can be directed on to unseen targets. The Aircraft Direction Room, besides being the centre of the Fighter Direction Organisation, is also (in Battleships and Cruisers, where the T.I.U. is in the A.D.R.) the centre for the blind distribution of gunfire. The A.D.R. is one of the main rooms in the A.I.C.

6. The A.D.O. decides from prevailing conditions whether target indication will more profitably be from the T.I.U. or the A.D.O.'s sights, and positions the T.I.U./Sight changeover switch accordingly. In either case the T.I.O., who is the gunnery link with the Plot, must work in the closest co-operation with the A.D.O. As the T.I.O. will need to be forewarned of raids detected by the long-range W.A. set and out of range of his guns and Types 293/M, he must also work in close co-operation with the F.D.O. This becomes very necessary when raids come within range, so that pursuing fighters may be directed to keep clear, or alternatively, fire can be withheld if the fighters are on their tails.

7. In ships where the Target Indication Officer is in a separate office from the Plot, the Gunnery Liaison Officer stationed in the Aircraft Direction Room is the gunnery link. It is his duty to keep the T.I.O. informed of the situation as regards aircraft targets.

8. To enable the T.I.O. to carry out his duties he is provided with the necessary communications and target indication gear. Target indication unit Mark IIB (Photograph 1) and Mark IIA (Photograph 2) have been designed for this purpose and provide target bearing and a means of indicating it to a number of selected positions, according to the class of ship. The whole unit can be fitted in the Aircraft Direction Room or installed in a separate office; in both instances it will be in the charge of the Target Indication Officer. One operator is required to work the T.I.U., Mark IIA, and two for the T.I.U., Mark IIB. In addition, one operator is required for each Ranging Outfit R.T.B. associated with the unit.

Objects of the T.I.U.

9. The object of the T.I.U. is, in conjunction with Radar W.C., Types 293/M, to detect and display all gunnery targets within the range of the Radar sets, so that selected targets can be indicated to different sections of the armament, and the A.D.O.'s and P.C.O.'s sights, with sufficient bearing and range accuracy for them to be picked up by the individual fire control Radar sets. Watch can be kept for targets outside the range of the W.C. set which may have been located by the long-range W.A. set, and once they come within the range of the W.C. set, their bearing and range can be indicated in the above manner.

Page 1. Insert new paragraph 9(a):-
9 (a). An alternative though less efficient T.I. system, known as the interlinking unit, is fitted in some small ships. It is designed to transmit bearing from Radar warning sets to R/F directors fitted with Type 285 via the R.T.U. and thus enable a target to be indicated to the main armament. Detailed information of the interlinking unit is given in B.R. 1634 (5). (G.06692/47.-C.A.F.O. P.84/47.)

How the Objects are Attained

10. The Radar W.C. set has a continuously rotating aerial system, and targets on any bearing within the range of the set will be detected. The receiver of the W.C. set feeds into a 9-in. Target Position Indicator (T.P.I.) the trace of which is rotating in synchronism with the aerial system. Therefore all targets detected will be plotted on the screen and become visible as a small sausage shape (called a "paint") extending over a small arc of bearing which will compare with the width of the beam from the W.G. set. The centre of the "paint" is the true bearing of the target.

(C56071) B4

 

Diagram I.
1944-1945 Capital Ships, Cruisers and A.A. Ships
Outline Plan of Aircraft Plot and T.I. Room
 

3
 
11. The T.P.I. display is in terms of true bearing, obtained from a fixed true bearing ring, north always being at the top. Own ship is at the centre of the T.P.I. Relative bearings are shown by a compass-controlled relative bearing ring, with an indicator showing ship's head against the true bearing scale.

12. The aerial array is rotating at a speed between 61 and 15 revolutions per minute (depending on the control table fitted and the speed setting in use) and the screen of the T.P.I. has a fairly long "after-glow," so that the "paint" from a target is only just fading when the next "paint" occurs. On to the T.P.I. a projected line of light can be aligned over the centre of the "paint," and in so doing the relative bearing of the target is transmitted away to a selected position where it is indicated on a magslip receiver. In the long-range H.A. director, when the trainer follows this indicated bearing, he automatically transmits back to the T.I.U. the bearing on which he is trained and hence enables the operator at the T.I.U. to see that the director is following his indication. The approximate range of the target can be read off as the projected line of light has range nicks marked on it: For more accurate transmission of range it is necessary to use the R.T.U. 53, two of which are fitted in each Ranging Outfit R.T.B.

13. A ranging outfit has been designed for this purpose, known as Ranging Outfit R.T.B. One outfit is fitted with each T.I.U. IIA and two outfits with each T.I.U. IIB, and each ranging outfit is controlled by an operator. Each Outfit R.T.B. displays two separate traces on a Panel L.37 showing Radar echoes, and, associated with each signal trace, a ranging strobe trace. The positions of the ranging strobes (finger type) ace controlled by R.T.U.s 53 and each Outfit R.T.B. is thus capable of transmitting the range of two targets. Transmission of range is vital for Type 262; it is also transmitted to Type 275 and Type 285 to assist them in picking up the target.

Where the T.I.U. is Fitted

14. As detailed in C.B. 3090, most classes of ships fitted with fire control Radar and hence capable of blind fire will eventually be fitted with a T.I.U., Mark IIA or B. Normally it will be fitted into the Aircraft Direction Room, and if this is not possible it will go in an entirely separate Target Indication Room which must be sited as close as possible to the Aircraft Direction Room. (Operations Room in destroyers and sloops.) When a separate office is used, a G.L.O. must be stationed in the A.D.R. to keep the A.D.O. and T.I.O. informed of the situation as regards long distance air warning and fighter directions. Otherwise, the T.I.O. acts as a liaison between the F.D.O. at the Main Display Plot and the A.D.O.

Page 3. Insert new paragraph 14(a):-
14 (a). Besides this liaison an auxiliary aircraft plot is part of the standard equipment of the air defence position in capital ships, cruisers and aircraft carriers, upon which filtered information, given by the air teller line, is plotted. To enable relative bearings to be quickly read off, a dummy ship dial operated by the gyro compass is fitted-a hole being cut in the centre of the plot.
(G. 06692/47.-C.A.F.O. P.84/47.)

15. In carriers the T.I.U. will always be sited in a separate target indication room, because of increased fighter direction requirements and the importance of reducing noise level. When- ever the T.I.U. is sited in a separate office it is advisable to have a replica of the Main Display Plot, which can be kept up to date by a "teller" line. Diagram I shows the layout of the Aircraft Direction Room of a battleship. Diagrammatically, the position of the T.I.U. can be clearly seen, with the sector display panels (Panel L.37) on either side and the full operating team consisting of the T.I.O. and four operators. A 3-section T.I.U., Mark IIA, will be fitted in small ships and a 5-section T.I.U., Mark IIB, in large ships.

Paragraph 16. Delete and substitute:-
16. Typical transmissions from a 5-section T.I.U. (T.I.U., Mark IIB) are as follows:-

No. 1 section, to port after director, A.D.O. sight and close-range weapons in port after "corner" of the ship.

No. 2 section, to port forward director, A.D.O. sight and close-range weapons in port forward "corner" of the ship.

No. 3 section, to the P.C.O.'s sights, T.S. and interrogator aerial.

No. 4 section, to starboard forward director, A.D.O. sight and close-range weapons in starboard forward "corner" of the ship.

No. 5 section, to starboard after director, A.D.O. sight and close-range weapons in starboard after "corner" of the ship.

With reference to Section 3 of the T.I.U., a bearing matching receiver is fitted in the T.S. over the A.F.C.T., to enable the table to be tuned to T.I.U. bearing.
(G. 06692/47.-C.A.F.O. P.84147.)

16. Typical transmissions from a 5 section T.I.U. (T.I.U. Mark IIB) are as follows:
No. 1 Section; to port after H.A. director, A.D.O. sight and closer-range weapons in port after "corner" of the ship.
No. 2 Section, to port forward H.A. director, A.D.O. sight and close-range weapons in port forward "corner" of the ship.
No. 3 Section, to the P.C.O.'s sights, T.S. and interrogator aerial.
No. 4 Section, to starboard forward H.A. director, A.D.O. sight and close-range weapons in starboard forward "corner" of the ship.
No. 5 Section, to starboard after H.A. director, A.D.O. sight and close-range weapons in starboard after "corner" of the ship.

17. This layout is applicable to 4-cornered carriers and battleships and, in general, is the standard arrangement for cruisers. In certain cruisers, where the armament is more suitably dealt with by an ended arrangement, the layout is arranged to suit. In small ships where a 3-section T.I.U. (T.I.U., Mark IIA) is fitted, the following arrangement (1942 "Battle" Class, not Leader) is typical.

No. 1 Section, to both port Bofors mountings.

No. 2 Section, to the Director, Tallboy and Interrogator Aerial and by power to the T.I. Sight.

No. 3 Section, to both starboard Bofors mountings.
(See also Plates 4 and 5.)

18. The above layouts may, of course, have to be altered to suit the individual ships and provision is made to do this. Each T.I.U. section has a blank plate near the handwheel so that on installation, the positions it controls can be engraved on the plate.

 

4
 
Limitations

19. The rotation speeds of the aerial array are fixed at installation, but alternative speeds are available by changing the gear ratios inside the aerial control table (6 2/3 or 10 revolutions per minute, 10 or 15 revolutions per minute, or 7 1/2 or 15 revolutions per minute). With these speeds very close range targets with a high bearing rate will be difficult to follow on the P.P.I. screen; furthermore, when the ship is rolling lack of full stabilisation will result in a bearing error which may differ with successive "paints" due to the cant of the aerial array.

The speeds available are 6 2/3 or 10 r.p.m. for Control Table 20J, 10 or 15 r.p.m. for 20G, 7 1/2 or 15 r.p.m. for 20H, and are designed to allow all types of target to be followed and plotted down to fairly close ranges. Control Table 20H which will eventually supersede the other control tables, is instantly switchable from 7 1/2 to 15 r.p.m. and vice versa, so that advantage may he taken of the lower speed for detection at greater ranges and of the higher speed for following fast moving targets at close ranges.

20. The T.P.I. has a 9-in. screen but only 8 in. can be usefully employed for display purposes which gives a range scope between 1,000 yards and 15,000 yards. By means of a switch on the T.P.I. the upper limit of the range scope can be varied to 30,000 yards and 75,000 yards. It can be switched to operate from the Types 277 or 291 (if fitted) as an alternative to the Types 293/M.

Accuracy

21. Types 293/M have a very narrow beam in the horizontal direction which at half amplitude is roughly 5 degs. wide in the horizontal plane and 65/45 degs. respectively in the vertical plane. It is capable of detecting and fixing for slant range and bearing all surface and high flying targets within the range scopes mentioned in the previous paragraph at distances varying with the size and nature of the target and at elevations between 20 mins., and 65/45 degs. This is a very general statement, but a more accurate idea of the capabilities of the set will be obtained if reference is made to the coverage Diagram (Appendix II). (A.U.J. for Type 276, A.U.R. for Type 293 and A.Q.R. for Type 293/M.)

22. The bearing discrimination which it is possible to achieve on the T.P.I. is approximately 5 degs. but this will depend to a large extent on the type of targets detected. Range discrimination is approximately ±400 yards. The degree of bearing accuracy which it is possible to obtain from the T.P.I. will depend upon and vary with the rate of change of target bearing. It varies from roughly 1/2 deg. when bearing rate is 1/2 deg./sec. to roughly 2 1/2 degs. when bearing rate is 3 deg./sec.

Paragraph 22. Add:-
The bearing accuracy is affected by the wander of the electrical centre of the T.P.I. trace, which may be considerable. The transmitted bearings are further affected by the error in the optical system due to the curvature of the T.P.I. and the angles of projection from the projectors.

The wander error can only be kept to a minimum by adjustment of the T.P.I. The error in transmitted bearings should not exceed ±22° at maximum range if the lining-up instructions in the amended paragraphs 182 to 186 are carried out. Errors at the lower, and more important, ranges will be considerably less than this amount.
(G/G.D. 225/46.-C.A.F.O. P.120/46.)

23. This variation of accuracy is due to the fact that the last visible "paint" on the T.P.I. lags behind the present bearing of the target and the lag will be greatest at high bearing rates.

Performance

24. The maximum working ranges on which it is possible to keep track of targets on the T.P.I. when working with Types 293/M are expected to be approximately as follows:-

  293 293M
Aircraft 15,000 yards 18,000 yards
Cruisers 25,000 yards 28,000 yards
Carriers 27,000 yards 30,000 yards
Battleships 29,000 yards 32,000 yards

I.F.F.

25. As at present fitted it is not possible to give direct indication of I.F.F. on the T.P.I. and separate interrogation is thus provided.

26. An Indicator Outfit, J.H.I., will be fitted beside the T.I.U. adjacent to the T.P.I. The trace displayed is controlled by the handwheel of the T.I.U. centre section (Section 3 in T.I.U., Mark IIB) which operates the sector selector switch in that section. To interrogate a target the handwheel of the centre section is turned until the projected line of light is aligned with the desired "paint" on the T.P.I. So doing will bring the target echo into view on the cathode ray tube of Panel L.43 and direct the interrogator aerial at the target. When a switch is made indication of I.F.F., if present, is given on the J.H.I. (see paragraphs 102 and 103). To avoid the L.A. armament necessarily imagining that a target is being thus indicated to them, a lamp and switch are fitted to tell them when to follow.

Communications

Page 4, paragraph 27. Delete and substitute:-
27. The T.I.U. operator, by means of the telephone switch provided on each section of the T.I.U., can link into the A.D.O., group concerned. The T.I.O. has a telephone with a C.O.S. which enables him to link into either operator's group. Each section of the T.I.U. has an alarm switch incorporated which operates the check-fire bells and lamps in the H.A. director and guns controlled by that section. Lights are provided in each section of the T.I.U. to indicate to the operator when the H.A. director is "ON" visually or by Radar. The close-range weapons controlled by each section have "switch and lamp boxes" above that section, each of which contains a switch which operates the check-fire bells and lamps and a light which combines the duties of visual and Radar "ON". The main line of verbal communication is the armament broadcast system; a typical arrangement of this for a cruiser is shown in Plate 6. In destroyers and small ships fitted with a T.I.U., a 3-in. V/P is fitted between ?? sight(c) on the compass platform, terminating in bell mouth over the T.I.O. chair.
(G. 06692/47.-C.A.F.O. P.84/47.)

27. The T.I.U. operator; by means of the telephone switch provided on each section of the T.I.U., can link into the A.D.O., group concerned. The T.I.O. has a telephone with a C.O.S. which enables him to link into either operator's group. Each section of the T.I.U. has an alarm switch incorporated which operates the check-fire bells and lamps in the H.A. director and guns controlled by that section. Lights are provided in each section of the T.I.U. to indicate to the operator when the H.A. director is "ON" visually or by Radar. The close range weapons controlled by each section have "switch and lamp boxes" above that section, each of which contains a switch which operates the check-fire bells and lamps and a light which combines the duties of visual and Radar "ON." The main line of verbal communication is the armament broadcast system; a typical arrangement of this for a cruiser is shown in Plate 6.

 

5
 
Other Publications

Page 5. Delete paragraphs 28 and 29 and line 15 "30-40" and substitute:-
Armament Broadcast System in Capital Ships, Cruisers, Aircraft Carriers and Monitors

28. An armament broadcast system is fitted to enable officers in general control of the armament, or responsible for indicating targets, to pass orders quickly and emphatically without an intermediary communication number. In capital ships, cruisers generally and monitors, it comprises a P.C.O.'s group and an A.D.O.'s group. In aircraft carriers and A.A. cruisers, both are combined into a single group.

Particulars and requirements of the system are given in subsequent paragraphs and Appendix IV, but in general, the P.C.O.'s group enables the P.C.O. to address the whole of the main surface armament, and the A.D.O.'s group enables the A.D.O. (or his assistants) to address the whole of the anti-aircraft armament.

The respective target indicating officers, viz., the G.L.O. at the main armament T.I.U. in the ops. room (if fitted) and the T.I.O. at the target indicating unit, Mark II, in the T.I.R. or A.D.R., can also speak on the appropriate groups. A change-over switch is provided in the T.I.R. so that the T.I.O. may also connect his microphone to the P.C.O.'s group and address the main armament alternatively to the A.A. armament.

In addition to the A.A.D.O.s normally stationed in the A.D.P., provision is made in capital ships and large cruisers for an after A.A.D.O. The after A.A.D.O. has, in the after A.D.P., a change-over switch which enables him to connect his microphone to the main system, or to isolate the after group of A.A. weapons from the main A.D.O. group, so that they are directed only by himself.

In all cruisers with a surface armament and a separate long-range A.A. armament, the assumption is made that the A.D.O. directs the A.A. armament when in surface control, as well as in A.A. control. To enable the P.C.O. to give general directions to the A.D.O. regarding the A.A. armament against surface targets and for starshell, speakers on the P.C.O.'s group are fitted in the A.D.P. This serves to keep the A.D.O. "in the picture" in a surface engagement, and enables the P.C.O. to issue his instructions to all sections of the armament by the same microphone.

29. In capital ships with a dual purpose A.A./surface secondary armament, it is also possible to change over the loud speakers at these guns, and those in their directors and H.A.C.P.s to the P.C.O. group, by means of a switch in the A.D.P. In these ships also, speakers on the P.C.O. group, fitted in the A.D.P., permits direction of the secondary armament for surface firings by the A.D.O. under the general direction of the P.C.O., as for the A.A. armament of cruisers.

30. The term T.I.R. is used to indicate the target indicating officer's position, although, in the majority of ships, it is within the aircraft direction room instead of being a separate target indication room. This should not he confused with the main armament T.I.U. in the ops. room.

Loud and Quiet Speakers

31. A loud speaker is one which effectively covers the whole of an area or compartment. They are provided to carry messages of over-riding importance.

A quiet speaker is one whose message is intended only to reach a man stationed in its immediate vicinity. It may be provided to serve as a loud speaking telephone or as a monitor at a microphone position of a loud speaking system. The siting of quiet speakers depends on the manning of the area or compartment and in some cases it may be necessary to site two, three, or more quiet speakers to serve a number of operators in that area, e.g., the A.D.P.

Any particular pattern of speaker may be loud or quiet, according to its volume adjustment and the position in which it is fitted.

28. This book gives a detailed description of the Target Indication Unit and its "Correct operation and maintenance but only lightly touches the ancillary apparatus associated with the problem of target indication.

29. For fuller information on the technical side of the equipment and ancillary apparatus or on drill procedure reference should be made to the following publications:-
H. 546 Preliminary Notes on Types 276/277/293. Parts I and II.
H. 546 Preliminary Notes on-Types 276/277/293. Part III (diagrams only).
B.R. 984 Radar Operating Procedure. Part II. Drill for Gunnery Radar Sets.
C.B. 4364 Handbook on the Universal Sight.
C.B. (R) 4298 Handbook on the P.P.I. and T.P.I.
C.B. 4291 Handbook on Type 242.
R.H. 649 Preliminary Handbook for Ranging Outfits R.T.B./R.T.E. (includes Panel L.37 and R.T.U. 53 (old name R.T.U. design 3) ).

32. Outfits of armament broadcast equipment will be referred to as:-

Outfit ABS Armament broadcast capital ship.
ABA Armament broadcast aircraft carrier.
ABC Armament broadcast cruiser.
ABM Armament broadcast monitor.

Appendix IV gives some details of microphones, loud and quiet speakers, change-over switches, amplifiers, etc., in a broadcast system.

33.

Action information intercom. system. }
} In destroyers and small craft.
}
Armament broadcast system.
Radar reporting line.

"Tribals" and later classes of Fleet destroyers, "Hunt" class, "Black Swan" sloops, "Bay" class A.A. frigates and fast minelayers are fitted with the above systems of communications. In "River" and "Loch" class frigates and "Castle" class corvettes it is approved to fit an action intercom. system which combines the functions of the action information intercom. and the armament broadcast systems.

34. The Action Information Intercom. System enables the rapid passing of information from all sources to the command, operations room and other positions. Similarly, filtered information from the operations room can be passed rapidly to the command and control positions for action.

35. The Armament Broadcast System enables the rapid passage of fire distribution orders to the gun armament either from the compass platform or the T.I.R. Orders can be given to torpedo tubes' crews, depth charge positions, ahead throwing weapons, and repair parties. Additional microphones and speakers are positioned so that reports of possible surface and air targets can be made from the upper deck aft and low down.

36. The Radar Reporting Line consists of a sound-powered telephone group and serves as a means of passing Radar information to the plot, and also provides a link for target information to the gunnery Radar operator and the T.I. position. A telephone handset on the compass platform enables the bridge to listen in. In the event of failure of the action information intercom. system, the Radar plotting line together with existing telephones and V/Ps can be used to maintain communication.

37. Short titles are used for the various systems in destroyers and small craft as follows:-

Action Information Intercom. Systems
Outfit A.I.D. For destroyers.
A.I. SL. For A.A. sloops and frigates.
A.I. ML. For fast minelayers.
Action Intercom. System
Short title. Outfit A.I.S.S.
Armament Broadcast System
Outfit A.B.D. For destroyers.
A.B. SL. For A.A. sloops and frigates.
A.B. ML. For fast minelayers.

Other Publications

38. This book gives a detailed description of the target indication unit and its correct operation and maintenance, but only lightly touches the ancillary apparatus associated with the problem of target indication.

39. For fuller information on the technical side of the equipment and ancillary apparatus or on drill procedure, reference should be made to the following publications:-

B.R. 1769. Preliminary Notes on Types 276/277/293. Parts I and II.
B.R. 1769(A). Preliminary Notes on Types 276/277/293. Part III (diagrams only).
B.R. 984. Radar Operating Procedure. Part II. Drill for Gunnery Radar Sets.
B.R. 1709. Handbook on the Universal Magslip Sight.
B.R. 1561. Handbook for Indicator Outfit J.E. (P.P.I. Gramophone Company Design).
B.R. 1439. Handbook for Type 242.
B.R. 1506. Preliminary Handbook for Ranging Outfits R.T.B./R.T.E. (includes Panel L.37 and R.T.U. 53 (old name R.T.U. Design 3)).
B.R. 1512. Preliminary Handbook for Indicator Displays, J.H.1, J.H.2 and J.J.1. (Panel L.43.)

(C.06692/47.-C.A.F.O. P.84/47.)
 

6
 

CHAPTER II
DESCRIPTION OF RADAR, W.C., TYPES 293/M, AND W.S., TYPE 276

Equipment in the Office

41. The office for Types 293/M is situated as near the aerial array as practicable and also if possible adjacent to the target indication room. The layouts of individual offices may differ slightly but will contain the Types 293/M transmitter and receiver and -also the Type 242 equipment.

42. In front of the operator is the Types 293/M control table. On the front of the table are fitted the aerial bearing indicator, the main training handwheel, the Type 242 training handwheel and the Types 293/M emergency training handwheel. This latter is normally kept in the stowed position. A P.P.I. is also fitted in the office.

The Aerial Arrays

43. The aerial array used with Type 293 is designated A.U.R. and with 293/M, A.Q.R. These arrays consist of cheese-shaped parabolic reflectors which are fed from the transmitter by waveguides. The wave guide passes through the aerial pedestal which carries the reflector and terminates in a flare mouth at the front of the reflector. The whole assembly is light enough for it to be mounted on one of the masts; in destroyers the aerial is mounted on a latticework mast.

44. The aerial is normally rotated continuously in one direction by a power drive Selsyn. This, however, may be stopped, and the aerial may then be rotated in either direction by either hand training wheel in the office. An "M" type step-by-step transmitter is driven by gearing from the pedestal turntable and transmits aerial relative bearing to the office. A lining-up contact is also driven from the turntable and is adjusted so that it causes a lamp in the office to burn when the aerial array is directed dead ahead. The lamp will flash at every turn of the aerial and thus indicate to the operator that the aerial is rotating and serve as a check that the aerial and displays are correctly lined-up. A similar lamp is fitted to the P.P.I.

45. The interrogator, Type 242, forms part of the target indication system and the aerial array used is of dipole formation designated A.S.R. The aerial is supported on a pedestal and is driven from the "follow-up switch" (see Plate 3) by a 1/10 h.p. D.C. motor. The pedestal turntable operates an "M" type step-by-step transmitter and a lining-up contact which burns a lamp in the office when the aerial is directed dead ahead.

The Aerial Control Table. Plate 3

46. The A.U.R./A.Q.R. aerial pedestal is controlled by a control table 20 G., 20J or 20H, which is situated in the Types 293/M office. It consists mainly of a gear box having three ingoing drives, and one main output shaft driving the Selsyn transmitter. The three ingoing drives are, power training motor, handwheel and compass correction motor.

The power training motor and Selsyn transmitter are mounted on a base-plate underneath the gear box and are coupled by chain drives to the gearing. A bearing indicator mechanically driven from the gear box is mounted on the front of the control table.

47. The handwheel and the training motor drive into an external type spur differential gear, the handwheel through non-reversing gears into one sun wheel and the motor through non-reversing gears into the planet carrier. The green output (true bearing) drives to an intermediate shaft-and thence into one sun wheel of a second differential gear. The planet carrier receives compass correction from the yellow drive. The mauve output (relative bearing) drives the Selsyn transmitter which feeds the Selsyn motor in the A.U.R./A.Q.R. aerial pedestal.

Control Table Bearing Indicator

48. This bearing indicator has two mechanical drives from the gear box; one from the green intermediate shaft which drives a pointer and indicates aerial compass bearing against a fixed scale, and one from the yellow compass correction motor which drives a relative bearing scale. The relative bearing scale is concentric with the fixed scale so that it indicates aerial relative bearing against the pointer and ships head against the fixed scale.

49. Two lining-up knobs are fitted to the front of the indicator; the knob for the pointer being in the centre and the relative bearing scale knob being at the bottom. At the top is the lining up neon lamp for the A.U.R./A.Q.R. aerial.

Interrogator Aerial Follow-up Switch

50. This is fitted in the right-hand part of the control table and controls the interrogator aerial motor. The motor can be controlled via the follow-up switch and a C.O.S. by either the centre section of the T.I.U. or a hand control in the Radar office.

 

7
 

LINING-UP DETAILS

Types 293/M

51. Full details of the starting up and lining-up procedures are given in H.546, Preliminary Notes on Types 276/277/293 but a brief summary is included here for the guidance of the Gunnery Officer.

(i) Switch on main switch, Selsyn supply switch and dial light switch and train the Types 293/M A.U.R./A.Q,R. aerial dead ahead by the handwheel. This will be indicated by the lining-up lamp on the bearing indicator burning.

(ii) Ascertain ship's head and set the relative bearing scale on the bearing indicator to ship's head on the fixed scale; then move the pointer by means of the centre knob until it is reading zero relative bearing, i.e., ship's head.

(iii) Set the aerial gyro repeaters to zero and check that all relevant T.P.I.s and P.P.I.s are lined up to ship's head. Switch on P.P.I. transmitter switch.

(iv) When ready to start continuous sweeping the control table driving motor is started up.

Type 242

52. (i) Set the hand/follow-up C.O.S. to hand and with the appropriate supplies switched on turn the training wheel until the Types 242 A.S.R. aerial is dead ahead. This will be indicated by the Type 242 lining-up lamp burning.

(ii) Set the aerial gyro receivers to zero. Now by turning the training handwheel the aerial array may be put on to any bearing by observing the pointer on the A.G.R.

(iii) Confirm that the centre section of the T.I.U. is fore and aft. Then put the C.O.S. to T.I.U. and the interrogator aerial may then be controlled from the T.I.U.

53-60.

 

8
 

CHAPTER III
DESCRIPTION OF T.I.U., MARKS IIA AND IIB

61. The instrument consists of three main components. (See Photographs 1, 2 and 3.) They, are, the Target Position Indicator (T.P.I.) the target indication box and the optical projection system, which is the link between the two other components. All three are mounted on a common framework, the target indication box being mounted at the front and at an angle, to facilitate operation, while above it is the T.P.I. The T.P.I. is mounted on rollers running on rails, so that it can be withdrawn for servicing requirements. Above the T.P.I. is the complete optical system, consisting of an adjustable plane mirror mounted at an angle on an outrigger bracket. A bank of projectors with graticules and focusing arrangements is mounted behind the mirror.

The T.P.I. (See Plate 3)

62. The T.P.I. has a 9-in. screen on which is displayed a trace showing the ground wave and echoes. The echoes appear as bright sausage shapes extending over an arc which is comparable with the width of the beam from the aerial array; the centre of the arc is taken to be the target bearing. The scanning coils producing and rotating the trace are made to turn at the same speed as the aerials array by an "M" type transmitter and receiver combination, giving movement in 1/2 deg. steps; thus when correctly lined-up the trace will rotate in synchronism with the aerial array.

63. Due to "noise" in the Types 293/M receiver, the trace is always visible as a thin "speckled line," and when the aerial sweeps through a target bearing, extra brightness of the trace causes a "paint" to appear on the bearing and at the range of the target. This extra brightness causes a slight change of colour to the trace where the "paint" appears, which greatly assists in identifying targets.

64. Round the T.P.I. are two graduated rings: an inner fixed ring showing true bearing with north at the top and an outer ring showing relative bearing and fed with gyro compass. The relative ring shows ship's head and stern by self-evident shapes, and is coloured to show 4-cornered sectors to facilitate putting the right director on to the target.

65. On some P.P.I.s, other than the one fitted in the T.I.U., it may be found that a transparent cursor supported on ball bearings covers the whole of the screen, and on it is marked from the centre outwards in triangular fashion, three range scales: 0-15,000 yards, 0-30,000 yards and 0-75,000 yards. The appropriate range scale is aligned to any particular "paint" by hand by the cursor rotating stud. When used with T.I.U., ranges will be obtained from range nicks (see Plate 2) on the projected lines of light. To reduce the effect of unwanted reflections on the screen face and to provide some local illumination for reading the scales in a semi-darkened office, four blue-coloured dial lamps and an amber filter over the cursor are provided. The amber filter reduces the yellowish light of the trace spots very little, but increases the contrast whereas any light which might cause reflection has to pass twice through the filter and is thereby considerably reduced. This particularly applies to the dial lamps which illuminate the scale through the uncoloured portion of the cursor, since blue is the complementary colour to amber. The filter will prevent light from falling on to the T.P.I. screen when the office door is opened in daylight, which might cause the screen to glow excessively when the door is shut again and dark conditions obtain.

66. In order to keep the lining-up conditions stable throughout operation gyro compass is fed into the control table as well as to the relative bearing ring. To accomplish this, gyro compass is fed to a Mark X compass repeater with step values of 10 minutes, in the control table 20G/ J/H thence to a torque amplifier and differentially applied to the output shaft. Thus the aerial will be corrected for movement of the ship and the scanning coils, and hence the trace, will be kept lined-up.

67. A Mark VI "M" type transmitter is driven from the intermediate shaft in the control table and energises the Mark III repeater motor driving the scanning coils in the T.P.I. This repeater motor is housed in an aluminum casting over the scanning coils and has a step value of 1/2 deg. An alternative type of repeater motor (Admiralty, Pattern P1730) is provided for in the wiring thus enabling alternative types of ships' gyro systems to be accommodated.

68. The aerial scanning motor and compass motor are fitted with spring-loaded lining-up knobs. All "M" type motors are supplied with 24 volts D.C. Plate 3 shows the connections between the Control Table, T.I.U. and T.P.I. and Radar sets.

Working Controls

69. The front panel of the T.P.I. mounts the following controls for setting-up and operating the instrument:-

Brightness.-This adjusts the intensity of the trace and, in conjunction with the Input control, must be adjusted so that a very faint trace appears on the screen.
 

Photo of TIU
Photograph 2. VIEW FROM LEFT-HAND SIDE OF T.I.U. MARK IIB
(CERTAIN COVERS REMOVED).
C36071
 

Photo of TIU
Photograph 3. VIEW FROM RIGHT-HAND SIDE OF TAX. MARK IIB
(CERTAIN COVERS REMOVED).
 

9
 
Input-This control adjusts the gain of the amplifier portion of the T.P.I. It should be adjusted so that noise shows as a speckled background on the screen and echoes are "painting" satisfactorily. It should be noted that discrimination between strong echoes may be improved by reducing- the amount of input leaving the brightness unaltered.

Focus.-This affects the sharpness of the trace and also the calibration spots.

Cal. Spot Brightness.-In conjunction-with the focus control this should be adjusted to give very sharp calibration spots. The control itself actually affects the intensity of the calibration spots.

Dial Lamp Brightness.-A small dimmer is worked by this control to vary the amount of local illumination reaching the face of the T.P.I. Only a very dim light should be used.

Range A Control.-Once the calibration spots have been initially adjusted by the use of this control and a pre-set control at the side of the T.P.I. called the Range A Linearity Control, the Range A control is only used to correct any difference between the calibration spots and the range scale engraved on the cursor or the range nicks on the projected lines of light. A similar function is performed by the Range B and Range C controls. The Range A control covers maximum ranges between 15,000 and 50,000 yards, the Range B control between 25,000 and 110,000 yards and the Range C control between 40,000 and 210,000 yards (normally set at 15,000, 30,000 and 75,000 yards respectively).

Each control has its own pre-set linearity control at the right-hand side of the T.P.I.

70. The following switches and indicator lamps are fitted at the front of the T.P.I.:-

Calibrator Switch.-When this switch is made, the calibrator spots will be super-. imposed on the trace.

Signal Lamp Switch.-This switch puts in circuit the "aerial forward" signal lamp. When this lamp burns it indicates that the aerial array is dead ahead and this can be used as a check to see that the trace is correctly lined up with the aerials.

There are in addition a main supply switch, a dial lamp switch, four blue coloured dial lamps and the "aerial forward" signal lamp.

THE T.I.U. BOX

Principle of Operation of the T.I.U. Box

71. The T.I.U. box can consist of either three or five similar sections, a three section box being very easily converted to five by removing the right end cover and coupling up two more sections. Each section is capable of relative bearing transmission to, and reception from the director to which it is connected, and has a handwheel which controls, via a flexible shaft, a corresponding graticule in the optical projection unit. This projects a line of light on to the face of the T.P.I.

Page 9, paragraph 72. Delete and substitute:-
72. The drive from the handwheel is in terms of true bearing and after gyro compass has been differentially applied to it, the resultant relative bearing shows on a rim pointer on a dial in the unit and operates one 3-in. and one 2-in. magslip transmitter. The 3-in. transmitter is a power magslip and controls the A.D.O. sight, via the receiver selector switch, and the 2-in. magslip indicates to the director concerned through a T.I.U./Sight C.O.S. in the A.D.P. This enables the A.D.O. to decide whether the director should be controlled by the A.D.O. sight or by the T.I.U. The centre unit of the T.I.U. transmits in a similar manner by power to the P.C.O. sight and by indicator to the surface armament.

It should be noted that T.I.U. transmissions have no stops, whereas A.D.O./P.C.O. sights and the RY 15 relay through which they are operated have stops fitted in order to prevent damage to the cables. This "linking", between round and round transmissions and instruments fitted with stops, presents some difficulty in the T.I.U. "calling" the sight, and a correct drill must be carried out at the sight. Therefore, if it is desired to follow T.I.U. the sight must first be trained somewhere near the middle of its training arc before being switched to T.I.U. If the sight then runs to its stop, it should be switched off, as the transmission is on the sight's "dead arc". With sided sights having 235° of training, the sight should be trained to within 60° of the beam before being switched to T.I.U. If it then runs to its stop, it shows that the T.I.U. bearing is on the other side of the ship, and the sight should be switched off.
(G.06692/47.-C.A.F.O. P.84/47.)

72. The drive from the handwheel is in terms of true bearing and after gyro compass has been differentially applied to it, the resultant relative bearing shows on a rim pointer on a dial in the unit and operates One 3-in and one 2-in. magslip transmitter. The 3-in. transmitter is a power magslip and controls the A.D.O.-sight, via the receiver selector switch, and the 2-in. magslip indicates to the director concerned through a T.I.U./Sight C.O.S. in the A.D.P. This enables the A.D.O. to decide-whether the director should be controlled by the A.D.O. sight or by the T.I.U. The centre unit of the T.I.U. transmits in a similar manner by power to the P.C.O. sight and by indicator to the L.A. armament.

73. Lamp indications are provided on each section to enable the T.I.O. to see when the director has picked up the target (1) by Radar when a blue lamp burns or (2) visibly when a white lamp burns, and each section has a spring return switch which operates the check fire bell and lamp at the director. Switches are also provided on each section for the T.I.U. operator's telephone so that he can link his head-set into the A.D.O.'s group concerned and switch on the appropriate projector lamp. Instrument illumination is provided to the dials. In later instruments lamps A.P. 629R.M. are fitted and a dimmer is provided. In the earlier instruments lamps A.P. 629M were fitted and the illumination was too bright; these lamps should be exchanged for the red ones A.P. 629 R.M. and dimming should be arranged by the use of paper or some similar material.

74. The transmissions to the H.A. directors appear on the red pointers of the Director Training units via the change-over switch which should normally be kept in the "Target Indication" position (the other being from own or other H.A. systems). The transmission to the main armament appears on the red pointer of a bearing matching receiver in the T.S. to which the main armament table can be tuned, the director following the table. Alternatively the P.C.O.'s sight can be power driven on to the indicated bearing by the T.I.U. and the D.C.T. can follow the P.C.O'.s sight, all this being done simultaneously with the transmissions to the bearing matching receiver in the T.S. Existing ships retain Evershed transmission between P.C.O.'s sight and D.C.T., but in later ships this transmission is magslip and a change-over switch is fitted in the D.C.T. to decide whether the red pointer in the Director Training unit receives from the P.C.O.'s sight or from the table.

 

10
 
75. The above refers only to the long range H.A. directors. The arrangements for the close range directors are described in paragraph 28. The indications in No. 3 Section are from the two P.C.O.'s sights and can be used as telephone call-ups, or as indications that the target has been sighted.

Description a the T.I.U. Box. Plate 1

76. The five sections constituting the box are identical except for section No. 2 in a three-section T.I.U. and section No. 3 in a five-section T.I.U. In these two sections an extra flexible drive is taken to the interrogator aerial transmitter or 242 gear box, mounted in close proximity to the T.I.U. somewhere on the bulkhead, and, which transmits relative bearing to the interrogator aerial (see paragraph 85). Plate 1 shows a three-section T.I.U., and the blue handwheel of unit No. 1 can be seen to drive mechanically, via the flexible drive, the appropriate graticule in the projector unit, and thereby aligns the projected line of light to the plot on the T.P.I. To enable relative bearings to be transmitted from the T.I.U., the handwheel drives into a differential which is fed by the yellow shafting with ship's head. The pink output from the differential then drives the 2-in. indicating and the 3-in power magslip.

77. In order that the operator can see the relative bearing he is transmitting, the differential output also drives the mechanical pointer of the magslip relative bearing receiver. The magslip pointer of this receiver indicates director training. (In ships fitted with H.A.C.S., Marks V or IV directors, table training comes from the H.A. table. From the blue shafting a drive is taken away to the blue selector pinion on which is mounted the selector switch operating stud.

Sector Selector Switch

78. The sector selector rocker arm is turned by the green shafting at the same speed as the aerial array and the sector selector will therefore operate each time the rocker arm passes over the operating stud. As the sector selector is connected so as to operate one trace in the cathode ray tube of the appropriate panel L.37, this trace will only become visible over a certain arc as determined by the position of the operating stud.

79. The operating stud is positioned by the true bearing of the section of the T.I.U. so that the trace on L.37 represents a Type A scan for an aerial trained on the bearing of that section. The limits of operation of the switch are normally ± 4 degs.; that means that the switch is closed 4 degs. before the aerial reaches the bearing of the T.I.U. section and opened 4 degs. later. Coarse adjustment of the contacts is effected by moving the contact assembly bodily on the supporting rods, and fine adjustment is obtained by movement of the contact adjusting screw. The method of setting this adjustment is described in Chapter V , paragraph 182.

80. The green shafting is driven by the aerial chaser motor and aerial bearing is indicated on the green aerial bearing dial. The aerial chaser motor is controlled by a normal type of hunter which is fed on one side by the chaser motor and on the other side by an "M" type motor fed from the aerial control unit. As there is separate provision to switch the aerial chaser motor in the T.I.U., it is possible for it to be started up out of step with the aerial array driving motor. To prevent these motors from running out of step a wrap-up device is fitted to the hunter.

81. This consists of two discs, the working disc containing the gate and the selector disc with five radial slots cut in it. When the hunter is out of centre the contacts are operated by the output from the differential and closed. This runs the chaser motor until one of the slots in the selector disc and the gate are in line when the hunter will recentre. The hunter will now remain centred and remain so during operation thus ensuring that the chaser motor and the "M" type motor are running exactly in step.

82. An exactly similar hunter is fitted to control the compass chaser motor, but the "M" type motor instead of being half a degree step value is of 10 minutes step value. The compass chaser motor drives via the yellow gearing on to the yellow shafting and thus applies compass correction and at the same time it indicates compass on the yellow compass dial. Both dials have lining-up knobs adjacent to them and are operated by pressing down and turning; this disengages the serrated clutch but not the drive to the hunter.

83. Arrangements are made to enable the T.I.U. to work with Type 277 as an alternative to Type 293. When this is done the transmission of aerial compass bearing to the T.I.U. and T.P.I. must be changed over from 293 to the alternative set. This transmission is "M" type and it is necessary to ensure that the aerial is correctly lined up after the C.O.S. is operated. At present it is necessary to stop the aerial of the set to which the T.I.U. has been switched when it is right ahead; the aerial compass bearing dial of the T.I.U. is then lined up to the true bearing of the ship's head as, ,s own on the compass dial and the T.P.I. scanning coil is lined up so that the trace on the T.P.I, is in line with the ship's head on the relative bearing ring (see paragraph 168 (iii)).

 

11
 
Aerial Auto-aligning

84. It is intended to fit a system of auto-aligning in the near future so that the T.I.U. will be automatically aligned when the aerials are switched over. Briefly, it provides that if the aerial and T.I.U. are not correctly in line, the aerial compass bearing motor in the T.I.U. is stopped with the dial pointer at 12 o'clock: it remains locked in that position until the aerial passes through true north again when the motor re-starts in synchronism with the aerial.

The system depends on cam-operated switches, one driven in synchronism with each aerial to which the T.I.U. can he switched, and one in the T.I.U. itself. The normal position of these switches if the T.I.U. and the aerial are correctly in line, is one open and one closed, and they both operate each time the aerial is at true north. If the aerial and T.I.U. are not exactly in line, one switch operates before the other, energises a relay and the "M" type aerial compass bearing motor in the T.I.U. is switched off, and is electrically locked. When the aerial next reaches true north the aerial switch opens, releases the relay and re-starts the "M" motor. The system is dependent on the "M" motor being stopped immediately the relay operates so that the associated cam operated switch remains closed: it is dependent also on the "M" motor restarting at once in synchronism with the aerial.

84a. The above system has been tried with the T.P.I. scanning coil but is not practicable as owing to the inertia of the scanning system the necessary instantaneous stopping and starting of the system cannot be achieved. To enable the T.P.I. to be lined up without stopping the aerial an electronic ship's head marker is being introduced. On switching over it will then be necessary to line up the electronic marker with the fore and aft line on the relative bearing ring. This can be done while the aerials are rotating by means of a small handle on the front of the T.P.I.

Interrogator Aerial Transmitter Drive

85. The drive to this transmitter is taken from the centre section of the T.I.U. In Plate 1, with a T.I.U., Mark IIA, it is shown coming from No. 2 section, whence it goes via a flexible drive to the gear box situated somewhere convenient on the back of the T.I.U. casing or on the bulkhead. This gear box contains an "M" type motor driven by compass (10 minute step value); this and true bearing from the flexible drive, drive into a differential which turns an "M" type transmitter. The "M" type transmitter, of 1 deg. step value, therefore turns in accordance with the relative bearing of the centre section.

86. The T.I.U. operator in aligning the projected line of light to the "paint" on the T.P.I. works the transmitter, and the associated receiver at the interrogator aerial turns the aerial to the required bearing. By making the interrogator switch on the T.I.U. any response to I.F.F. is obtained on the Indicator Outfit J.H.I. as described in paragraph 102.

The Projector Unit and Optical System. Plate 2

87. There are five identical projector units mounted in an arc on a framework over the T.P.I.; the three-unit T.I.U. of course having only three projectors. The projectors face the operator and the light from them strikes an adjustable plane mirror set at such an angle that the light line is deflected down on to the face of the T.P.I. Each projector is coupled to its appropriate unit in the T.I.U. box by a flexible drive.

88. The drive enters at the rear of each projector on the left-hand side where it engages with a worm wheel surrounding the graticule housing. The housing actually contains a lens, a condenser and a piece of sensitised glass on which is photographed the graticule line and the six range marks. The whole of this assembly is supported eccentrically in the housing, and this allows for any necessary adjustment to get the mid-point of the graticule line coincident with the optical axis. The housing is so positioned and locked by the manufacturers and must on no account be disturbed.

89. It should be noted here, that due to the projector units being mounted on an arc and each projecting on a different spot on the plane mirror, slight variations in the positions of the range marks will be noticed on the face of the T.P.I. when the optical system has been correctly lined up. The error is variable up to a maximum of 500 yards, but it is only apparent when two or more lines are brought into coincidence in certain positions on the T.P.I. face, when it will be seen that the range markings on the two or more lines do not coincide. This lack of coincidence is small at the short range end of the lines and greatest at the long range and as no great accuracy is required it has been accepted.

90. A light retaining tube connects the graticule housing to a ball bearing at the opposite end of the unit. In front of this ball bearing is another lens in an eccentrically positioned mount. The mount is correctly set and focused by the manufacturers so that its optical centre is coincident with the mid-point of the projected graticule line, and on no account must it be disturbed. A lamp is mounted at the drive end of the projector unit and the amount of illumination it provides is controlled by a rheostat fitted adjacent to it.

(C56071)

 

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91. The line of light from the projector unit is thrown on to the plane mirror and deflected down on to the face of the T.P.I. The mirror is locked by two hand screws and adjustable on a ball joint and once correctly set so that the mid-point of the projected line of light is central on the T.P.I. screen, it need not be disturbed. The procedure for lining-up the projector units is given in Chapter V. As explained above, each projector unit is correctly set up by the manufacturers with sufficient tolerances allowed to enable a projector to be used with any T.I.U. and produce a sharp clear line focused on the glass screen of the T.P.I.

Ranging Outfit R.T.B. Photograph 4

92. Ranging Outfit R.T.B. comprises Panel L.37, two R.T.U.s 53 (or R.T.U.s 52 in M-type transmissions) and two strobe generators. The sector display panel L.37 is essentially a cathode ray tube displaying two Type A traces mounted over two range transmission units R.T.U. 53. Two-panel L.37s are fitted, one on either side of the T.I.U. for transmission of range to Radar Type 262 on close range weapons, as described in paragraph 13, and to assist the G.A. Type 275 on Mark VI or Mark 37 directors and Type 285 on earlier directors to pick up a target quickly. One panel L.37 and two R T.U. 53s will be fitted with T.I.U., Mark IIA.

93. The screen of the cathode ray tube has an "afterglow" effect and the trace appearing is derived from the Types 293/M set, via the sector selector switch in the T.I.U. This switch makes the trace "alive" only each time the aerial beam crosses the bearing corresponding to the position of the rim pointer and projected line of light of the associated section of the T.I.U.

94. In effect the combination of the tube afterglow effect and the sector selector switches, "takes the spin" out of the rotating aerial and allows detailed examination of a bearing sector (not exceeding 8 degs.) to be made, without the necessity of stopping the aerial array.

95. Two-panel L.37s would display four traces. Thus the upper trace of the left-hand panel L.37 could be controlled by No. 1 section of the T.I.U. and the lower trace by No. 2 section. No. 4 and No. 5 sections could control the lower and upper -traces respectively of the right-hand panel L.37. The R.T.U. 53 controls a linear type strobe which is made to move along the trace when obtaining the range of a target echo. The range is transmitted by magslip.

R.T.U. 53. Photograph 4

96. Two R.T.U. 53's are mounted beneath the cathode ray tube of each Panel L.37. Each has a handwheel fitted to the front which is used for tuning and ranging, also a drum type range scale marked off in 300 divisions, with main divisions numbered 0-15. A switch underneath the strobe generator varies the range scope of the R.T.U. from 0-10,000 yards (short), 0-40,000 yards (medium) or 0-100,000 yards (long). A stop is incorporated in the medium scope which reduces its upper limit to 36,000 yards. An internal lamp is provided to illuminate the drum scale and different coloured indicator lamps show which range scope is in use:- 0-10,000 yards, amber lamp; 0-40,000 yards, green lamp and 0-100,000 yards, red lamp. The scale illumination lamp is in series with the outgoing supply to the magslip receiver, and acts as a pilot lamp to show that the circuits are alive. Cut pushes for the R.T.U. operator indicate to the armament concerned when a correct range cut on L.37 is obtained.

97. The handwheel of the R.T.U. 53 controls the mechanism positioning the linear strobe on the trace of panel L.37, and to obtain the range an echo it is only necessary to turn the handwheel and set the strobe to the leading or left-hand edge of the echo. The range will then be automatically transmitted by magslip.

98. It is very important that the R.T.U. is correctly set up, as described in R.H. 649 Handbook on Ranging Outfits R.T.B./R.T.E., and the index correction applied if necessary. Most R.T.U.s will need this and it is found by carrying out an accurate range test at about 3,000 yards. It should be applied and the amount of the correction logged, with the date. It should be noted that both the R.T.U. 53 and Panel L.37 have switches with which to change the range scopes and that they are independent of each other. The switch for altering the range scope of the trace on Panel L.37 is on the panel itself and for altering the range scope of R.T.U. 53 the switch is on the associated strobe generator.

99. If the scale of the L.37 panel is altered without altering the scale of the strobe-generator (commonly known as the "scale of the R.T.U.") the strobe remains on the target echo. Now, scale 1 possesses the advantage of greater magnification and, therefore, greater setting accuracy, while scale 2 has the advantage of greater range scope; but changing the scale of the panel L.37 has no effect on the outgoing transmissions.

100. If the change-scale switch on the strobe generator is moved from scale 2 to scale 1, the strobe moves to the left by an amount which corresponds to a range of 1/3.6 times the previous reading. The R.T.U. handle is then turned to move the strobe back to the echo and the correct range is then transmitted on the new scale. This switch also operates signal lamps to show which scale is in use.

 

TARGET INDICATION UNIT, MARK IIA, WITH RANGING OUTFIT R.T.B.
(C56071)
 

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101. To obtain the greatest accuracy of transmission at low range, it is necessary to switch both the panel L.37 and the strobe-generator to scale 1. The range limits of the panel L.37 are at present (i) 0-15,000 yards, (ii) 0-30,000 yards, (iii) 0-75,000 yards.

A new R.T.U. is being designed which will transmit accurate ranges simultaneously to Type 262 and Type 275 without the necessity for changing range scales.

Indicator Outfit J.H.I. (I.F.F. Panel L.43)

102. The interrogation display is shown on a similar panel to L.37 but is designated Indicator Outfit J.H.I. This panel is fixed convenient to the T.I.U. and shows two traces. The upper trace is fed from the Types 293/M set via the sector selector switch in the centre unit of the T.I.U., and the lower trace is fed from the Type 242 set.

103. As the screen of the cathode ray tube has afterglow properties, a continuous presentation of targets on a particular bearing is obtained, i.e., in conjunction with the sector selector the rotation of the Types 293/M aerial appears to be stopped on the bearing of the centre section of the T.I.U. To establish the identity of a target seen on the T.P.I. it is thus necessary to put the line of light of the centre section over this target; this shows the target on the upper trace of the J.H.I. cathode ray tube. By closing the I.F.F. switch the lower trace will show an inverted echo of the coded I.F.F. response under the target echo if the target is showing I.F.F.

Close Range Armament

104. Bearing indications from each section of the T.I.U. are transmitted not only to the long range H.A. directors, but to close range weapons or directors in the same "corner" of the ship. It is therefore necessary to have a method of passing the Alarm to individual close range directors so that they will know when to follow T.I.U. pointers and when a movement of these pointers is due simply to a target being indicated to another director in the same sector.

105. On either side of the P.P.I. in a T.I.U., Mark JIB, is a steel plate which carries SWITCH AND LAMP BOXES (see Photograph 2). Each sideplate carries two columns of switch and lamp boxes, each column being associated with one of the sections (less the centre section) of the T.I.U. Each close range director or self contained gun mounting which can be controlled by a section has a switch and lamp box in the appropriate column above that section. In the case of centre line weapons a two-position C.O.S. is fitted at the top of one of the side-plates so that the T.I.O. can select which section the weapon is to be controlled from. Each switch and lamp box comprises a spring switch which operates the check fire circuit to the weapon concerned and a "Target" lamp which is normally lit either by a "Target Visible" switch at the director or by a "Radar Target" switch at the Radar bearing tube. Each box is tallied to show the weapon controlled. Centre line weapon boxes have a flap marked "OWN" and "OTHER" which is hand operated to agree with the position of the C.O.S. referred to above: in the "OTHER" position operation of the check fire and alarm switch is prevented. T.I.U.s, Mark IIA, are sometimes also fitted with smaller sideplates, depending on the number of weapons fitted.

Note.-"Self contained weapons" above refers only to Bofors, Mark IV, Staag, Buster or similar weapons.

106. Each switchbox associated with a centre-line director has on it a flap, one side of it being marked "OTHER" and the other side "OWN". These flaps are put over by hand to agree with the position of the change-over switches, and indicate that the weapon concerned is switched to the other side. When the flap is placed to "OTHER" it projects under the Alarm- switch and prevents it being depressed.

107. Plate 4 shows a typical layout in a four-cornered ship without details of the above switching for close-range armament, but showing in general the various indications which can be achieved. Angle-of-sight transmissions are shown from the T.I.R. but it devolves on the T.I.O. to distinguish on which target the Type 277 is obtaining angle of sight. This he does by observing the Type 277 aerial bearing indicator in the T.I.R., and hence arranges for that angle of sight to be transmitted to the appropriate tallboy. Plate 6 shows how the P.C.O., A.D.O. and T.I.O. can link into the armament broadcast system in a cruiser, when broadcasting warnings of impending attacks.

108. As will be seen in Plate 4 the angle-of-sight transmitter which is situated by the H.P.I. transmits angle of sight, as given by the scale on the H.P.I., to a selector switch in the target indication room. By means of this selector switch, Type 277, angle of sight can be indicated to the E.C.U. of the tallboy in the H.A.C.P.

109-110.

(C56071)

 

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CHAPTER IV
PROCEDURE FOR TARGET INDICATION

PART I-GENERAL

Functions of the A.I.C.

111. The action information centre is often described as the nerve centre of the ship, and this description is a very sound one so long as the simile is confined to the nerves of sight, sound, touch, smell and hearing, i.e., the nerves which convey to the brain, the presence, position and description of some object in the vicinity. The brain corresponds to the Command and it devolves on the brain to decide what action is required.

112. A highly trained and well equipped A.I.C. corresponds to a sensitive nervous system, which is quick to react and can be relied on to sum up available information and present the essential features to the brain in a way which will enable the brain to decide, in the shortest time and with the least difficulty, what action to take.

113. The more highly trained and experienced the system is, the more "reflex" its actions will be and the more subconscious will be the decisions reached by the brain as a result. The brain, however, must remain the deciding or discriminating factor and the nervous system must remain its servant. This simile has been thus expanded to show the lines along which the training of the A.I.C. and its gunnery component, the T.I.R., must proceed and to control any desire on the part of the A.I.C. to "run the show" without proper liaison with and reference to the Command.

Interpretation of T.P.I. "Pictures"

114. The correct interpretation of the "picture" on the T.P.I. screen is not easy at first and needs considerable experience, therefore drill at the T.I.U. must be like clockwork so as to get the armament on the targets in the least possible time. T.I.O.s and the T.I.R. crews must be given exhaustive training in interpretation of T.P.I. pictures and exercise in the various forms of attack.

115. Diagrams II to V show pictures obtained from the T.P.I. of a ship escorting a convoy. The pictures are numbered in order and represent the various stages of a combined high level, dive-bombing and torpedo attack on the convoy. The white tracks have been put in by hand to show the actual course taken by the attacking planes, to help clarify their movements, as the photographs are instantaneous and would not show the track for any appreciable time. The gain control has been reduced to give a clearer picture and the range scope in use is 0-15,000 yards. Diagram II shows the enemy formation as a single "paint" at a range of 14,500 yards, just before splitting up for the attack, with No. 2 section line of light aligned with the enemy bearing and No. 4 on the leading ship of the convoy, which is 5,500 yards from the escort ship.

Diagrams III to V show various stages of the attack; the course of the high level bombers, which attacked first, being marked by a dotted line. The dive bombers attacked next and their course is marked by a dot-and-dash line, while the torpedo attack was made last, the course of the aircraft being marked by a dashed. line. Only one "paint" will be observed for each group of aircraft in these pictures owing to their close formation keeping, but it is quite possible for single aircraft in a formation to give a "paint" if they are flying sufficiently far apart. Diagram VI shows the type of picture obtained if the gain control is increased to normal searching gain, thus increasing noise and allowing side lobes to become more visible than hitherto. Diagram VII shows a picture of another convoy which is sailing close to the Orkneys, of which the extreme tips of the islands are seen on the right of the picture.

116. From this it will be seen that the T.I.O. and T.I.U. crew must watch the P.P.I. constantly if the identity of all echoes is to be known with certainty. A careful study of the main air display plot in a cruiser or battleship and the filtered air plot in a carrier should leave no doubt as to the identity of aircraft echoes when they first appear at about 18,000 yards. Once inside about 10,000 yards, however, these plots are on too large a scale to be of much help so that it is essential that each echo is carefully followed.

Surface targets on the other hand must be identified by reference to the surface relative plot.

Further confusion may also be caused by false echoes from clouds, enemy Radar deception devices such as "window", or internal electrical faults; and enemy aircraft may use deceptive tactics by merging and breaking formations.

Lastly, every endeavour must be made to put directors on to targets at the longest possible range, since the greater the range the smaller the search in elevation necessary to detect the target.

Drill and Procedure

117. The following drill and procedure for the operation of the complete Visual/Radar target indication system is only provisional, and as sea experience is gained in the operation of the equipment, the need for alterations will become apparent. Any suggestions or observations as a result of practical experience should be forwarded through Administrative Authorities, with a copy to the Captain, H.M.S. Excellent.

 

Diagram II. T.P.I. Picture of Convoy Attack-First stage.
Diagram III. T.P.I. Picture of a Convoy Attack-Second stage.
 

Diagram IV. T.P.I. Picture of Convoy Attack-Third stage.
Diagram V. T.P.I. Picture of Convoy Attack-Fourth stage.
 

Diagram VI. T.P.I. Picture of a Convoy.  Gain Increased to normal searching gain.
Diagram VII. T.P.I. Picture of Convoy off the Orkneys.
 

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PART II-BATTLESHIPS, CRUISERS, AIRCRAFT CARRIERS-
A.A. TARGET INDICATION

Selection of Target Indicating Position

118. The A.D.O. will position the T.I.U/Sight change-over switches so that the Directors will receive from the A.D.O. Sights if targets are likely to be picked up visually before detection by the Radar Target Indication set, or from the T.I.U. during darkness and low visibility.

Target Indication by the A.D.O.

119. Switches will normally be as follows:-
T.I.U./Sight C.O.S. to SIGHT.
P.C.O. Sight switched to A.D.O.
A.D.O. Sight switched to FREE.

120. When a visual sighting is made, the appropriate A.D.O. Sight is trained and laid on the target, and the A.D.O. Sight is switched to STABILISED.

121. A.D.O. or A.D.O.'s "talker" broadcasts a warning. This goes to P.C.O. (if not switched off) and T.I.O. in A.D.R. (or T.I.R. in carriers). This alarm is also passed to the appropriate directors, H.A.C.P.s and guns by the check fire bells.

Target Indication by the P.C.O. (surface targets for the secondary armament of battleships and cruisers and main armament of carriers)

122. A.D.O.'s Sight is switched to P.C.O., and P.C.O.'s sight is switched to FREE and is then trained on the target. P.C.O. Sight is then switched to STABILISED.

123. The P.C.O. or the P.C.O.'s communication number keeps A.D.P. informed by the P.C.O.'s broadcast group. A.D.O. or A.D.O.'s talker broadcasts a warning to the armament. The alarm is also passed to Director, H.A.C.P. and guns by check fire bells.

124. A.D.O. can put A.D.O. Sight on by switching his sight to P.C.O. and CONTROLLED.

Target Indication by the T.I.O.

125. The T.I.U./Sight C.O.S. is switched to T.I.U. The T.I.U. crew will be closed up and operate as follows:-

T.I.O. Indicates targets to T.I.U. operators. Passes orders on A.D.O. broadcast system.
Right-hand T.I.U. Operator. Works Nos. 4 and 5 sections of T.I.U. Wears headset, with linking switches to starboard forward and starboard after H.A. group. (Linking switches should not be kept made. If both switches are made simultaneously both H.A. groups will be linked together).
Left-hand T.I.U. Operator. Works Nos. 1, 2 and 3 sections of T.I.U. Wears headset with linking switches to port forward and port aft H.A. group. (Linking switches should not be kept made. If both switches are made simultaneously both H.A. groups will be linked together.)
Right-hand Ranging Panel Operator. Transmits ranges of targets indicated by 4 and 5 sections to long and close range armament fitted with Types 262, 285 or 275.
Left-hand Ranging Panel Operator. Transmits ranges of targets indicated by 1 and 2 sections to long and close range armament fitted with Types 262, 285 or 275.

126. For example: a target detected at 15,000 yards on the starboard bow. T.I.O. orders the right-hand operator to put the starboard fore director on the target. The R.H. operator turns the handle of No. 4 Section of his T.I.U. to follow the echo on the T.P.I. with his line of light. As he does so, he also operates the check fire switch in No. 4 Section of the T.I.U. to ring the alarm at the starboard fore director, and H.A.C.P., and guns controlled by them.

127. The director receives the bearing and follows it, and in so doing causes the repeat pointer in No. 4 Section to follow the mechanical pointer. The T.I.O. can thus see when the director is on the bearing indicated. The director then searches in elevation and picks up a target with its Radar set. The R.H. operator also passes the approximate range of the target by telephone, to assist the Radar operator. Range from the R.T.B. is also passed to the G.A. Radar set to assist in picking up the target.

128. When the target is held, a range cut pedal or switch at the tallboy is operated, which also burns the blue light in No. 4 section. The director is now ready to open blind fire. If permission to open fire is necessary to comply with the policy in force, the T.I.O. will pass his orders by the A.D.O.'s broadcast.

129. If the director sights the target, the layer makes the target visible switch and a white light burns in No. 4 Section to inform the T.I.O.

Target Indication for Close Range Weapons by T.I.O.

130. As targets get closer to the ship themay require to put a number of close-range weapons on to a number of targets in quick succession.

 

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131. The sections controlling close-range weapons would be alloted as follows:-

No. 4 Section: No. 1 centre line pom-pom (C.O.S. on steel plate to NO. 4, and flap on switch and lamp box above No. 4 Section to OWN. Flap on switch and lamp box above No. 2 Section to OTHER.)
  No. 3 sided pom-pom.
No. 5 Section: No. 5 sided pom-pom.
  No. 7 centre line pom-pom.

The R.H. operator, to put No. 1 pom-pom on to a target, would ring its check fire bell at the same time turning the handle of No. 4 Section to bring his line of light on the new echo. This will not interfere with the starboard fore director because it is following the target detected by Radar, which is indicated to the T.I.O. by the blue lamp burning in No. 4 Section.

132. As soon as No. 1 pom-pom is on the bearing indicated, it will search in elevation until the target is detected, and as soon as it is a lamp in the switchbox above No. 4 Section will burn showing the T.I.O. that target indication to this weapon has been effected. This lamp is operated by a "target visible" switch on the pom-pom director or from the Type 282 range cut push.

133. The T.I.O. can then order the R.H. operator to put No. 3 pom-pom on to yet another target a similar manner Nos. 5 and 7 pom-poms can be put on to further targets by No. 5 Section.

134. In practice, it is probable that Nos. 4 and 5 Sections can be operated simultaneously, as the R.H. operator, once he has put his line of light on an echo need only keep it up to date for true change of bearing to target, and at picking-up range this should be slow, so that he should be able to work Nos. 4 and 5 Sections simultaneously with his two hands.

PART III-BATTLESHIPS, CRUISERS, CARRIERS-
SURFACE TARGET INDICATION

Target Selection

135. Surface targets will, in general, be selected by the Command in consultation with the Bridge Plotting Room Officer. The P.C.O., acting for the Captain, will then instruct the G.L.O. (see paragraph 142 below) and/or the T.I.O. accordingly, defining the targets by their track numbers (or letters) or by rough bearings and ranges.

Surface Target Indication by the T.I.O.

Page 16, paragraph 136. Delete and substitute:-
136. Surface targets which it is desired to engage can be indicated by the T.I.O. in a similar manner to the indication of aircraft targets. For this purpose the T.I.O. must have a clear view of the Surface Relative Plot, on which he can correlate the echoes seen on his T.P.I. with the track numbers or letters referred to by the P.C.O.

To enable rough relative bearings to be read off, a dummy ship dial, operated by the gyro compass, is fitted to the plot.

In some layouts with plotting from the front of the plot the ship dial is fitted centrally, in later layouts fitted with the standard Surface Relative Plot which is "Edgelit perspex" with plotting from behind, the ship dial is fitted in the right-hand upper corner.

In ships with the T.I.U. in the A.D.R. an enlarged arched opening, built in the bulkhead between the operations room and the A.D.R., sometimes contains the plot, visible to the O.R. officer, the T.I.O., and the direction officer.

The headset and breast transmitter at the T.I. position on the surface telling line serves this plot.

In ships with a separate T.I. room, the surface relative plot may be fixed to the lid of a convenient junction box in such a way that it can be removed when work is required on the box. A headset and breast transmitter on the surface telling line serves this plot.
(G.06692/47.-C.A.F.O. P.84/47.)

136. Surface targets which it is desired to engage can be indicated by the, T.I.O. in a similar manner to the indication of aircraft targets. For this purpose, the T.I.O. must have a clear view of a surface relative plot on which he can correlate the echoes seen on his T.P.I. with the track numbers (or letters) referred to by the P.C.O. (Where possible, the Ops. Room surface relative plot will be arranged so that it can also be seen by the T.I.O. in the A.D.R. Where this is not possible, a separate surface relative plot must be fitted in the A.D.R. or the T.I.R.)

137. Once the T.I.O. has identified the surface targets ordered on his P.P.I., he can indicate them to the appropriate section of the armament.

Separate Main Armament Target Indication in Battleships and Cruisers

138. In some battleships and cruisers the indication of targets to the main armament is being separated from the T.I.U., Mark II, with the object of ensuring that main armament target indication will receive its due attention irrespective of any air attack which may be occurring simultaneously.

139. Target indication is done by a separate main armament T.I.U. situated in the operations room. The T.I.U. consists of a simplified form of single section T.I.U. box which controls a projector unit to show a line of light on the W.S. P.P.I. This T.I.U. box transmits the relative bearing of any echo on the P.P.I. by power magslip to the P.C.O.'s sight via the sight control switch and by magslip indicator to a bearing matching receiver in the main armament T.S. and to the repeat pointer in the centre section of the T.I.U. in the A.D.R.

140. This main armament T.I.U. is operated by the gunnery liaison officer (G.L.O.) (see paragraph 142 below) who is equipped with the following communications:-

(1) A microphone on the P.C.O. broadcast.
(2) A quiet speaker on the P.C.O. broadcast.
(3) A telephone with C.O.S. and associated call-up lamps to:-
(i) The main armament control group.
(ii) The T.I.O. in the A.D.R.
(4) An alarm push to operate:-
(i) A gong and lamp at the P.C.O. sight.
(ii) A lamp at the hearing matching receiver in the main armament T.S.
(5) A true range receiver from the main armament T.S.
(6) A target compass hearing receiver from the main armament T.S.
 

17
 
141. Targets for the main armament will be selected by the Command in a similar manlier to that described in paragraph 135 above, and the G.L.O., as in the case of the T.I.O., must correlate by referring to the surface relative plot in the Ops. Room, the track number ordered and the echo on the P.P.I.

Duties of Gunnery Liaison Officer (G.L.O.)

142. Whether separated main armament target indication is fitted or not, a G.L.O. is required in the Ops. Room to fulfil the following duties:-


(a) To pass information of enemy course and speed to the main armament rate group, and in particular, to supply forecasts of enemy movements based upon tactical appreciation.

(b) To receive precise information of enemy course and speed from the main armament rate group for use at the L.O.P.

(c) To supply amplifying information to the A.A.T.I.O. when the surface situation presented on his relative surface plot requires elucidation.

Use of Starshell

143. Subject to the policy for the night, it may be desired to use starshell, either for searching, or in conjunction with the Main Armament or Secondary Armament.

144. If Starshell illumination is ordered by the P.C.O., the T.I.O. can indicate the target to the appropriate A.D.O. Sight which is then used for Starshell Control in the normal manner by the Starshell Control Officer.

145. If centralised starshell control arrangements are fitted, i.e., the starshell calculator is fitted in the main armament T.S., bearing to the starshell control is provided from the main armament fire control system, and no separate target indication for starshell purposes will be required.

Positions for Target Indication Switches

146. There are a large number of change-over switches fitted in connection with Target Indication Systems, and the functions of these switches vary with different classes of ships.

147. In order to operate the system efficiently it is considered advisable for ship's officers in each ship to extract the necessary information from the relevant Key Diagrams to enable them to draw up in tabular form, a statement of the positions to which switches should be put in different circumstances. In this handbook, a typical statement has been drawn up for the Target Indication System fitted in "Battle" Class destroyers (see Appendix I), which will serve as an illustration.

PART IV-DESTROYERS-A.A. AND SURFACE TARGET INDICATION

Target Indication Arrangements. (See Plate 5)

148. These are capable of the following functions:-

(a) T.I. Sight can transmit Bearing (Power) to the appropriate S/L sight.
(b) T.I. Sight can transmit Bearing (Indication) and Elevation (Indication) to the H.A./L.A. Director.
(c) T.I. Unit (which is fitted with 3 Sections) can transmit Bearing (Indication) as follows:-
No. 1 Section-Port Bofors mountings.
No. 2 Section-H.A./L.A. Director, and T.S.
No. 3 Section-Starboard Bofors mountings.
(d) T.I. Unit can transmit Bearing (Power) from No. 2 Section to the T.I. Sight.

Searchlight Training

149. The appropriate S/L Sight transmits Training (Power) to the searchlight. The sight can be stabilised by Gyro Compass, so that it will maintain a true bearing during alterations of course.

The S/L Sight can be controlled for bearing:-

(a) By Power from the T.I. Sight.
(b) By the S/L Sight operator, who may train on a visual target.

Searchlight Elevation

150. The appropriate S/L Sight transmits Elevation (Power) to the searchlight. The Sight can be stabilised by a gyro to compensate for roll. The S/L Sight is controlled for elevation by the S/L Sight operator.

Change-over Switches

151. Four change-over switches in connection with Target Indication are fitted on or near the bridge. Different combinations of these switches arc required for different tactical conditions and it is suggested that a board should be kept on the bridge, with a guide on the lines of that shown in Appendix II gummed on it. until men arc thoroughly familiar with all functions of the switches.

(C56071)

 

18
 
152. The selection of positions in for switches shown Appendix II has been governed by these considerations:-
(a) Director to receive from the T.I. Sight if targets are likely to be picked up visually before detection by Radar.
(b) Director and Bofors mountings to receive from the T.I. Unit during darkness and low visibility.

Switching Drill

153. It is essential that frequent drills are carried out to ensure that the bridge crew are familiar with the switching arrangements, and are ready to alter them rapidly to meet the changed conditions, using the quickest method.

154. The methods of target indication by the T.I.O. given in paragraphs 125-129 are generally applicable to the smaller and simpler equipment fitted in a destroyer. Here the T.I.O. is responsible for indicating both surface and air targets and so must maintain liaison with the L.O.P. and the air plot. This latter will normally be positioned in the T.I.R.

PART V.-SETTING UP DETAILS

Initial Setting Up of the T.P.I.

155. The full details of the procedure for initially setting up the T.P.I. are given in the relevant handbook C.B. 4298R., but a short summary is included here for the guidance of the Gunnery Officer. The basis of the procedure is to ensure that the trace is correctly centred on the screen and to adjust all the pre-set controls.

Centring the Trace

156. A small circle is engraved at the centre of the cursor and the trace is correctly centred when the inner end of the trace line is revolving concentrically with this circle. This is achieved by setting the controls to the minimum necessary to produce a trace line, and with the aerials rotating, adjusting the three rods positioning the focus coil until the above setting is obtained.

Adjusting the Pre-Set Controls

157. The aerial array must be stationary and the calibrator switch on, but the calibrator spot brightness and brightness controls must be adjusted until the calibration spots are sharp and clear, and the trace must be turned until range A scope coincides with the line of calibration spots. By use of the pre-set adjustments the calibration spots are made to agree with the range marks on the cursor, and when this is so, the pre-set adjustments are clamped in position. The other range scopes are then treated in a similar fashion and the trace can then be adjusted for normal operation.

Setting Up the Trace

158. The following method of setting up the trace can only be carried out if the above adjustments to the pre-set controls have been carried out.

(i) Turn the brightness control to a minimum and switch on the mains switch, then switch on the dial lamps and adjust the dial lamp brightness to the desired level.

(ii) The calibrator switch should now be put ON, the input control turned down to a minimum. Increase the brightness control until the trace appears as a very faint line and adjust the focus and calibrator spot brightness controls to give very sharp spots with only the slightest trace between them. Turn the projected line of light and check the calibration of each of the range scopes by means of the set range switch, and if they are correct turn the calibrator switch to OFF.

(iii) Line up the relative bearing ring by comparison with the master compass. With the input control set to the minimum, adjust the brightness until the trace is clearly visible and order the Radar set operator to set the aerial array dead ahead. By the lining-up knob turn the trace until it is at the ship's head. shape on the relative bearing ring. The brightness control must now be readjusted until the trace is just visible.

(iv) The aerial array must now be set in rotation and the input control increased until noise shows as a speckled background and weak signals, if available, are "painting" satisfactorily.

(v) If necessary readjust focus and brightness to obtain optimum results. It should be noted that the brightness control must be so adjusted that, when the input control is turned down to minimum, the trace appearing on the screen should be just visible.

159. On closing up for each watch it is advisable to check the calibration of the range scopes and if any discrepancy exists to recalibrate by means of the range controls range A, range B and range C. It is also advisable to check the alignment of the scanning coils and the aerial array. This is very simply done by switching in circuit the "aerial forward" signal lamp, which should burn at the moment the trace passes the ship's head position, and any misalignment eliminated by use of the lining-up knob as in (iii) above.

 

19
 
Lining-Up the T.P.I.

160. To ensure that the trace is indicating correctly against the compass ring, the relative position of the scanning coils to the aerial array must be set up in the following manner, using the lining-up knob at the side of the T.P.I. housing. The aerial array must first of all be turned until it is pointing ahead and maintained in this position. This is effected by the handwheel on the aerial control unit, and indication that the array is pointing ahead is given on the T.P.I. by the "aerial forward" signal lamp burning. On some aerial control units a signal lamp is incorporated, to serve the same purpose at the unit.

161. The zero on the relative bearing scale must now b2 set to ship's head, by use of the lining-up knob. The T.P.I. trace is now aligned to zero on the relative scale by pressing in the lining-up knob at the side of the T.P.I. and turning it until this condition is obtained. It will be found that the relative scale will hunt during this lining up, indicating that it is following the gyro compass, a necessary condition.

162. It will be found essential to de-energise the aerial repeater motor when using the lining-up knob to prevent a back drive occurring on to the motor. When lining up initially a check must be made to ensure that the rotation of the scanning coils, and hence the trace, faithfully reproduces the relative bearing of the aerial array; if it does not it will be due to one of the repeater motors being incorrectly connected, and in paragraphs 174 and 175 is given a method of determining which it is.

163-170.

(C56071) D2

 

20
 

CHAPTER V
ADJUSTMENTS AND TESTS

171. These adjustments and tests can be divided into-

(a) Erection adjustments and tests, carried out when the system is first installed and subsequently to confirm that the system is still in adjustment, and
(b) The lining-up and checking required when closing up or at the change of the watch.

(a) Erection Adjustments and Tests

These include the following:-

(i) Test to ensure that the aerial transmission is correct.
(ii) Test to ensure that the compass transmission is correct.
(iii) Tests to ensure that the transmissions to the directors are correct.
(iv) Alignment of sector switch.
(v) Adjustment of sector switch.
(vi) Adjustment of the optical system.
(vii) Tests to ensure that the aerials are correctly orientated.

These tests are described in paragraphs 174-197. (See Photograph 7.)

(b) Lining-up and Checking when Closing Up

On each occasion of closing up it is necessary to check:-

(i) The T.P.I. scan.
(ii) The T.P.I. compass ring.
(iii) The T.I.U. aerial bearing.
(iv) The T.I.U. compass transmission.
(v) The bearing and other transmissions to gunnery positions.

172. The tests for these have been referred to as follows:-

(i), (ii) and (iii) in paragraphs 51, 66-68 and 155-162.
(iii) and (iv) in paragraphs 79-82, and 155-162. (See Photograph 6.)
(v) has not been described in this book, as procedure is the same as for "checking receivers" in any fire control system.

173. Although the transmissions are magslip in all cases it is advisable on closing up and at the change of the watch to carry out the check procedure, to ensure that no transmission has failed for any electrical reason.

Checking Connection of Aerial Repeater Motor

174. Apply power to the aerial repeater motor. Turn the aerial in a known direction and check that the T.P.I. trace faithfully follows. If it does not, but moves in the opposite direction, any two leads to the aerial repeater motor must be interchanged. Check that the trace now faithfully follows the direction of rotation of the aerial.

Checking Connection of Compass Repeater Motor

175. Lock the aerial in a position facing dead ahead with respect to the ship and energise the aerial repeater motor and the compass correction motor in the control table. Obtain information as to compass bearing and then observe the direction in which the trace moves for a change in bearing. If the change is not in the correct direction, any two leads to the compass, Mark X, motor in the torque amplifier unit of the control table must be reversed. Check that the trace now moves in the correct direction for any change of bearing. Electrical connections of the T.I.U. (internal) are shown in Plate 9.

LINING UP OF THE T.I.U.

176. Before lining up the T.I.U. it is necessary to ensure that the directors and sights are lined up to the fore-and-aft line of the ship. This is normally done during the building period and must be carried out before the following.

Workshop Lining up

177. The initial lining up of the T.I.U. is accomplished in the following manner, and although the method is provisional its use is to be recommended. The cover plates of all sections (3 or 5) must first be removed and each section lined up in turn in a similar way. The method of lining up one section is described below.

178. After removing the cover plate the holding-down screws on the 2-in. and 3-in. magslip transmitters must be slackened off, and the magslip body rotated so that the lining-up pegs can be inserted from the front. Set the aerial array compass for dead ahead and by means of the friction grips set the aerial and compass dials to zero. Switch on the lamp in the appropriate projector unit.

 

Photo of TIU
Photograph 5. T.I.U., MARK IIB, WITH T.P.I. IN SERVICING POSITION.
(C65071)
 

21
 
179. The flexible drive to the optical unit must now be removed at the handwheel end, and the squared shaft turned by hand until the projected line of light on the T.P.I. is approximately at zero. Reconnect the flexible shaft, turning the squared end as necessary to effect re-engagement. Now by means of the handwheel turn the projected line of light exactly to zero. Loosen the friction grips on the relative bearing dial and turn the pointer exactly to zero. The magslip holding-down screws can now be tightened and the lining-up pegs removed. This is always done by the manufacturer before supply.

Installation Lining up on Board and Adjustment of the Optical System. (See Plate 2)

180. Each projector unit is secured by three bolts: one at the lens end on which the unit can be made to swivel, and two at the drive end. The two bolts at the drive end pass through slotted holes in the projector units and thus allow the unit to be swiveled. The following method should be used to line up the optical system so that the mid-point of each projected graticule line is central on the face of the T.P.I.

181. The centre projector must first be correctly positioned, i.e., with a three-section T.I.U. it is the projector corresponding to No. 2 section, and with a five-unit T.I.U. it is the projector corresponding to No. 3 unit. Loosen the bolts holding the projector and move the projector until the bolts are in the middle of the slotted holes, then tighten the bolts. Set the mirror so that the projected line of light is roughly central. Line up the compass dial to zero and check that it is still at zero when all readings are taken.

Paragraphs 182 to 187. Delete and substitute:-
182. Starting with the centre section, bring the "spot" at the end of the projected line to the centre of the fixed gyro ring (surrounding the T.P.I.) by adjusting the mirror. To define the centre of the gyro ring place two thin wires with their ends at 0° and 180°, and 90° and 270°.

183. Take readings of the section dial with the line of light at 0°, 90°, 180° and 270°. Mean the error by moving the line of light relative to the section pointer. This must be done by adjusting the vernier coupling in the driving shaft inside the section box. To obtain access to the coupling remove the cover plate on the underside of the section. The line of light must not be adjusted by rotating the optical parts. (See paragraph 88.)

184. Repeat with each section as for the centre section, except that adjustments to the position of the spots must be made by moving the projectors and not the mirror.

185. Lateral adjustment can be made easily by tapping the appropriate projector one way or the other on its seating. The adjustment is effected by means of the back securing bolts inside the projector box and the slotted holes. The front bolt should be only slightly eased. Vertical adjustment requires shims to be inserted either under the front or back holding-down bolt. The brightness of the projected lines can be adjusted by the rheostat in each projector unit (see paragraph 90). The lines should be of the minimum operational brightness, to avoid swamping weak echoes.

186. The limits of error in any section between the projector line and its associated mechanical pointer should not exceed ±2 1/2°. This should be checked by taking readings at 30° intervals, one set clockwise and one anti-clockwise, care being taken to keep each set of readings continuous in one direction (i.e., do not overshoot the reading and come back to it).

187.
(G/G.D. 225146.-C.A.F.O. P.120/46.)

182. Starting with the center section, bring the "spot" at the end of the projected line as to the centre of he fixed gyro ring (surrounding the T.P.I.) by adjusting the mirror. It will be found easier to do vertical and lateral adjustments separately, and to define the centre of the gyro ring by a thin wire placed at one end on 0 deg. and lowered carefully over the curved face of the T.P.I. on to 180 deg. at the other, for lateral adjustment, repeating this with 90 deg. and 270 deg. for vertical adjustment.

183. Closer vertical and lateral adjustment can then be made by reading off the scale end of the projector line. Thus, readings of 90 1/4 degs. and 269 1/2 degs. would indicate that the line is between 1/4 and 1/2 and deg. low, and adjustment should be able to bring this within a full 89 3/4 degs. on one side and a full 269 3/4 degs. on the other, lateral adjustment being carried out in the same way over the 0 deg. and 180 degs. readings.

184. The error between projected line and section dial should then be "meaned out" by adjusting the splined coupling in the base of the section. This may mean some further slight adjustment to the mirror, after which it should be clamped in position, checked again, and thereafter never disturbed.

185. Repeat with each section as for the centre section, except that adjustments must be made on the projectors themselves and not on the mirror.

86. Lateral adjustment can be made easily by tapping the appropriate projector one way or the other on its seating; an adjustment effected by means of the back security bolts inside the projector box and the slotted holes. The front bolt should be only lightly eased. Vertical adjustment calls for shims to be inserted either under the front or back holding-down bolts. The error should then be meaned-out as before, after which a further slight adjustment may be necessary. The brightness of the projected lines can be adjusted by the rheostat in each projector unit (see paragraph 90). The lines should be of the minimum operational brightness to avoid swamping weak echoes.

87. The following limits of error can be accepted between each projector line and its associated mechanical pointer on target indication units, Marks IIA and IIB, readings to be taken at 15 degs. intervals on the section dial, one set clockwise and one anti-clockwise, care being taken to keep each set of readings !s uniformly continuous in the one direction (i.e., do not overshoot the reading and come back to it). T.I.U., Mark IIA Section 1 ± 1 deg. Section 2 ± 3/4 deg. Section 3 ± 1 deg. T.I.U., Mark IIB Section 1 ± 1 1/4 deg. Section 2 ± 1 deg. Section 3 ± 3/4 deg. Section 4 1 deg. Section 5 1 1/4 deg.

Magslip Alignment.

188. Any final fine adjustment which may be necessary must be made at the transmitter indicating magslip. It cannot be done on the H.A. director line of sight unit, as if the C.O.S. is put to another position this receiver can be controlled by other transmitters. In the pom-pom director, Mark IV, the target indication dial is only controllable by target indication and the receiver magslip stator can he adjusted. It is thus necessary to align stators in the following order:-

(i) H.A. Directors by director test results.
(ii) T.I.U. to suit (i).
(iii) Pom-pom directors to suit (ii).
 

22
 
189. To adjust the transmitter stator in the T.I.U. it is necessary to slack off the magslip holding-down screws and rotate the body of the magslip by hand. The magslip must then be held while the screws are tightened. It must the remembered that if any adjustment is necessary here, the lining-up pegs will no longer be able to be inserted. Sufficiently accurate lining up of the T.I.U. should be obtained, however, without having to resort to this latter device.

Sectoring Switch Alignment. (See Plate 1)

190. The plunger arm operating the sectoring switch must be set to zero position while the T.I.U. is in the above state, i.e. lined up to zero. The plunger arm will be in the zero position when it is on the apex of the operating stud fitted to the gearwheel driven from the handwheel.

191. To do this, remove the back panel and slacken the three screws holding the lining-up wheel to the aerial input wormwheel. Remove the lining-up key from its housed position outside the casing and insert it in the hole in the wormwheel. Turn the key until the plunger arm is forced up on to the peak of the operating stud, tighten the three screws and remove lining-up key.

192. To line up the aerial bearing dial (Photograph 5), turn the aerial by hand until dead ahead, and then by loosening the friction grips turn the dial to bearing 0 deg. Tighten up friction gyro grips. The gyro compass dial also has friction grips and is simply lined up. With the main gyro stopped running but the "M" type transmission switched on, turn the gyro to any bearing and line up the compass dial to this bearing. This latter procedure can only be done when the gyro is not running such as in harbour.

193. The target indication box is now fully lined up, but the operation of the sectoring switch should be checked.

Sectoring Switch Adjustment

194. The sectoring switch should operate and remain closed while the aerial array sweeps over selected bearings. The limits of arc during which the switch remains closed are adjustable between ± 4 degs., e.g., the switch can be made to close up to 4 degs. before a selected bearing is reached by the aerial array and to open up to 4 degs. after. To obtain the best results it is recommended that the sector selector switches should operate within ± 2 1/4 deg. to 2 3/4 deg. of a selected bearing on the mechanical dial. Four readings should be taken at 90 deg. intervals.

195. These limits can be adjusted and checked in the following manner. Set the aerial array and compass dead ahead-as the initial lining up has been carried out this will now be indicated on the aerial and compass dials-and disconnect one side of the sector switch. Connect either a battery and voltmeter or battery and lamp across the sector switch contacts and move the contact-adjusting screw until the desired limits are obtained. This can be indicated on the relative bearing dial, if the handwheel is moved in either direction, so rocking the pointer of the dial either side of the aerial bearing.

196. Correct adjustment will be obtained when the pointer of the relative bearing dial is rocked an equal amount either side of the aerial bearing. If the desired limits cannot be obtained by means of the adjusting screw, the whole contact assembly can be bodily moved up or down the threaded support-rods to bring the limits within the scope of the adjusting screw.

Hunter Adjustment

197. To secure maximum sensitivity, the hunters controlling the gyro compass and aerial gyro bearing follow-up motors should be adjusted to be just on the point of hunting.

PROCEDURE FOR DISMANTLING. A T.I.U.

198. When they are received in ships, target indication units may be already assembled or be partially dismantled, according to the means by which they have been transported. Before erection in the ships they may require to be completely dismantled so as to pass through doors and hatches; the following instructions show how this should be done. See also Plate 8 which identifies the figures used below.

(a) Remove mirror brackets (9) and mirror assembly (10).

(b) Remove the T.P.I. (15) complete from its anti-vibration supports (11).

(c) Disconnect all flexible mechanical drives ((2) in Mark IIA and (3) in Mark IIB) from control boxes (1).

Disconnect all flexible electric cables ((4) in Mark IIA and (5) in Mark IIB) from control boxes.
Each complete control box can now be detached by removing swivel pins and hinges (6).

(d) Remove plate (7) complete, with projector unit (8) and flexible drives and cables.

(e) If the frame itself is to be dismantled, remove the cross-braces (12) and (13) from the main frame (14).

The various components are now easily transportable, the largest item being the T.P.I. frame sub-assembly (15), which will pass through an opening 2 ft. 6 in. by 2 ft.

199-200

 

Photograph 6. T.I.U. MARK IIB CONTROL BOX ON MAKER'S TRANSPORTER TROLLEY.
Photograph 6. T.I.U. MARK IIB CONTROL BOX ON MAKER'S TRANSPORTER TROLLEY.
 

Photograph 7. DIALS OF T.I.U.
Photograph 7. DIALS OF T.I.U.
 

APPENDIX I

FUNCTIONS AND POSITIONS OF TARGET INDICATION CHANGE-OVER SWITCHES-"Battle" Class Destroyers
(Not applicable to Leaders)

C.O.S. DESCRIPTION. SITED. POSITION OF C.O.S. DAY-
ACTION,
AIR
ATTACK
OR
CRUISING.
NIGHT CRUISING NIGHT ACTION.
1 C.O.S. for Training Control of S/L, Sight (2 in number). Adjacent to S/L Sights. Posn. 1-Gyro Compass Stabilised
Posn. 2-Free.
Posn. 3-Controlled.
2 3 4
2 C.O.S. for Elevation. Stabilisation of S/L Sight (2 in number) Adjacent to S/L Sights. Posn. 1-"Off."
Posn. 2-Gyro "On."
Posn. 3-Gyro and Pump "On."
1 2 3
3 T.I.U/Sight C.O.S. Adjacent to Target Indication Sights. Posn. 1-T.I. Sight.
Posn. 2-T.I. Unit. (Elevation "OFF.")
1
(2 in low visibility)
2 2
4 C.O.S. for Control of S/L Sights and Searchlight. Bridge. Posn. 1-S/L Sight Starboard controlling S/L.
Posn. 2-S/L Sight Port controlling S/L.
1 or 2 1 or 2 1 or 2 during air attack.
Training Control C.O.S. for Control Bearing (Power)
Drive for T.I. Sight.
In T.I. Sight. Posn. 1-Gyro Compass Stabilised.
Posn. 2-Free.
Posn. 3-T.I.U. Control.
2 3 3

Note.-Searchlight sights are now obsolescent and in some ships may have been removed.

(C56071) 1,500 11/45

 

APPENDIX II. COVERAGE DIAGRAMS FOR AUJ, AUR, AQR
Height in feet vs. Reliable pick-up range in yards.
 

23B
 

5 C.A.F.O. P.84/47

APPENDIX III


T.I.U., MARK II
Modifications to Existing Sights and Directors

A T.I.U. transmits and receives bearings by magslip and it is therefore necessary to arrange that P.C.O., A.D.O., and Pelorus sights and H.A. and R.F. directors can do likewise. The changes necessary to equipment consequent on the fitting of Till., Mark II, are as follows:-

Directors and R.F. Directors

(a) Mark VI Directors when fitted require no alterations.

(b) Mark V, V* and IV Directors. Magslip reception of target indication can already be received. Magslip transmission is arranged by making use of the transmission of table training from the Mark IV table.

(c) Mark III Directors.-Magslip reception is arranged by replacing the existing receiver for 285 bearing by a magslip receiver (R.309 series). Magslip transmission is provided by fitting a transmitter in the same box as the new magslip coarse/fine transmitter required for auto-control of gun mountings. Where fine (40°) auto-transmitters exist at present, new boxes are required as replacement when T.I.U. is fitted.

(d) "K" type towers require no alterations.

(e) R/F directors, Mark VI, require no alteration.

(f) R/F directors, Mark IIIW and IIW. Magslip reception of target indication is already provided. Magslip transmission to the T.I.U. is provided by a magslip transmitter in the same box as the new magslip coarse/fine transmitters required for auto-control of gun mountings; or if auto-control of gun mountings is not fitted, in a separate unit.

Notes.-1. These directors will not be removed from ships, but the additional gear will be supplied for installation by the refitting authority.

2. The R. 309 series receivers mentioned in paragraph (c) are supplied with 6 ft. of flexible cable for connection to the black pointer drive incorporated in the modified training gearboxes fitted in directors, when converted for scooter control.

P.C.O./A.D.O. Pelorus Sights

The fitting of additional transmitters to work with T.I.U., Mark II, is of a very simple nature and can be carried out by the refitting authorities, the necessary magslip training units being supplied.

(a) Captain's or P.C.O.'s Sight of general types. T.131, T.148, T.169. Magslip training units will be supplied. They will be fitted on board by the repair yard.

Important.-Only in cases where T.169 sights are to be converted to T.166 sights, are the T.169 sights to be returned to the makers.

(b) A.D.O. Starshell Sights of general Types T.160 and T.166. When Mark VI directors are NOT installed at the same time, magslip training units will he supplied and fitted as in (a) above. When Mark VI directors ARE installed at the same time, the sights are to be returned to the makers for fitting of magslip training and elevating units.

P.C.O./A.D.O. Sights-Installation

The fitting of target indication units requires great accuracy in the installation of P.C.O./A.D.O. sights. This can only be obtained by fitting suitably machined base plates.

The seating for the sight is to be a true plane, parallel to the datum plane of the ship, the maximum permissible deviation from parallelism being 30 mins. of arc.

A machined base plate should be fitted in lieu of a teak pad for any P.C.O./A.D.O. sight which is removed for modification or replacement.

(G.06892/47.-C.A.F.O. P.84/47.)

(C22162)

 

23C
 

6 C.A.F.O. P.84/47

APPENDIX IV


REQUIREMENTS OF MICROPHONES, LOUD AND QUIET SPEAKERS, CHANGEOVER, SWITCHES AMPLIFIERS AND OTHER COMMUNICATIONS AFFECTED IN AN ARMAMENT BROADCAST SYSTEM FOR CAPITAL SHIPS, CRUISERS, AIRCRAFT CARRIERS AND MONITORS

A. Microphones

(i) One in centre of A.D.P. for A.D.O.s use. A.D.O. group.
(ii) One each side of A.D.P. near A.A.D.O's use.
(iii) One in the after A.D.P. of capital ships and cruiser of the 8-in. "Town," "Fiji" and later classes for the after A.A.D.O.s use. (Used in conjunction with the amplifier for after sub-group and switchable to forward sub-group amplifier.)
(iv) One in T.I.R. for the T.I.O.s (switchable to either group).
(v) One at the R.C.M. control officers position in the B.P.R.
(vi) One at each P.C.O. sight for the P.C.O.s use. P.C.O. group if there is a separate P.C.O. otherwise A.D.O. group.
(vii) One at each D.C.T. forward for the gunnery officer's use, or in the forward control of ships not fitted with D.C.T.s.
(viii) One at the main armament T.I.U. In the operations room.
"(ix) One in the main armament T.S. of battleships and cruisers fitted with radar Type 274 (on P.C.O.s group) ".
(All hand microphones except (iv) which is bracket type.)

B. Loud and Quiet Speakers.

  Position. Speaker.
Loud. Quiet
A.D.O.
group
forward
sub-group.
(i) A.D.P. - 12608
(ii) After A.D.P - 12608
(iii) (a) Compass platform (for P.C.O.), or in carriers - 12608
  (b) Battle conning position - 12608
  (c) Closed bridge (for Captain) - 12608
(iv) T.I.R. - 12557
(v) Each director (forward groups only, if armament four cornered) 8888A -
(vi) Each C.P. (of forward groups only, if armament four cornered) 8888A -
(vii) Each Type 275 tallboy room (of forward groups only, if armament four cornered) 8888A -
(viii) Each A.A. turret or mounting (of forward groups only, if armament four cornered) 12554 -
(ix) Each casemate of B.D. mountings (forward groups only, if armament four cornered) 12554 -
(x) Each forward cluster of barrage directors, pom-pom directors and close-range weapons; positioned so that all can hear 12525 -
(xi) Each Type 282 office forward, which is wired for or fitted with remote scooter control 12557 -
(xii) Forward D.C.T. of a ship which has only one barrage director to control two forward turrets 8888A -
(xiii) B.P.R. for R.C.M. office (with ON/OFF switch) 12557 -
A.D.O.
after
sub-group.
(i) Each director aft, of a ship with four cornered armament - 12608
(ii) Each C.P. aft of a ship with four cornered armament 8888A -
(iii) Each Type 275 tallboy room of a ship with four cornered armament 8888A -
(iv) Each A.A. turret or mounting of the after groups in a ship with four cornered armament 12554 -
(v) Each casemate of B.D. mountings of the after groups 12554 -
(vi) Each after cluster of barrage directors, pom-pom directors and close-range weapons, positioned so that all can hear 12525 -
(vii) Each Type 282 office aft, which is wired for or fitted with remote scooter control 12557 -
P.C.O.
group.
(i) Each D.C.T. or Director 8888A -
(ii) Forward or after controls of cruisers not fitted with D.C.T.s control position in monitors 12554 -
(iii) T.I.R. - 12557
(v) T.S. annexe of "Town" class cruisers 8888A -
(vi) Each main armament turret 12554 -
(vii) Each director which can control the main armament 12608 -
(viii) Each C.P. associated with a director which can control the main armament 8888A -
(ix) Each Type 275 tallboy room associated with a director which can control the main armament 8888A -
(x) A.D.P. (but not the after A.D.P.) - 12608
(xi) Operations room at main a Maine armament T.I.U. - 12557
(xii) Compass platform for P.C.O. - 12608
(xiii) Torpedo tubes 12554 -

C. Change-over Switches

(i) One, two-position switch in the T.I.R. which will enable the T.I.O. to speak to the A.D.O. group or the P.C.O. group. This switch will be in the input circuit from the microphone in the T.I.R. to the amplifiers.

(ii) One "on" and "off" switch in the after A.D.P. where fitted, which will enable the after A.A.D.O. to isolate his microphone and the after sub-group. This switch will be in the input circuit from the microphone in the after A.D.P. to the amplifier for the forward sub-group. In the "On" position forward and aft microphones operate all speakers.

(iii) One two-position switch in the A.D.P. of capital ships, where the long range A.A. armament is also the secondary amplifiers surface armament, which will enable the A.D.O.s or P.C.O. to speak to Section (v) to (ix) forward and (i) to (v) aft, of the A.D.O. group. The switch will normally be in the output circuits from the amplifiers to the loud speakers.

(iv) A second switch (two-position) in the after A.D.P. in the output wiring from the after amplifier to the after sub-group of long range A.A. guns, which will disconnect this wiring to switch (iii) in the forward A.D.P. Its use is to isolate the of the after sub-group when necessary.

 

23D
 

7 C.A.F.O. P.84/47

Appendix IV-continued

D. Amplifiers

For most groups the average power consumption per loudspeaker is of the order of two watts. Amplifiers will be Pattern 12522A, capable of giving an output of 50 watts. A box of spare parts will be provided with each amplifier.

Amplifier dimensions are:-Width, 26-in.; height, 18-in.; front to bulkhead, 6-in.

A clear space of at least 2 ft. is required in front.

Electrical supply for amplifiers should be:-

(a) Power at 50 volts, 50 cycles from the ship's fire control system, should be used. Alternatively:-

(b) 230 volts, 50 cycles or 115 volts, 50/60 cycles, may be used.

Amplifiers, Pattern 12522A, will impose a standing load of 120 watts on the supply and the load may rise to a maximum of the order of 190 to 200 watts when speech is being transmitted.

E. Other Communications Affected

The installation of the armament broadcast system will render redundant certain arrangements at present fitted, or authorised to be fitted, viz.:-

(i) Additional loud hailing equipments for control of A.A. weapons.

(ii) Switch and plug boxes on the compass platform, connected to the A.D.O. telephone, close-range telephone groups, for use by O.O.W.

(iii) Multiphone communication between compass platform and/or A.D.P. and director tower, pom-pom directors and mountings.

(iv) Microphones and amplifiers fitted in A.D.P.s for use with A.D.O. telephone groups.

(v) Open fire circuits from switch and push boxes in the A.D.P. to lamps in the director towers.

(vi) Voice pipes, which in the opinion of ship's officers, are rendered unnecessary.

Notes.-(a) Special circumstances may require the fitting of additional speakers, or speakers of different patterns to those quoted, in certain positions. Any addition or change should be reported.

(b) It will be observed that directors which can control the main armament, associated H.A.C.P.s and tallboys, the A.D.P. and the T.I.R. will each have two speakers, one on the A.D.O. group and the other on the P.C.O. group.

(c) The circuit to a speaker in a main armament turret, which can be controlled by a barrage director for A.A. fire, will be taken through the barrage change-over switch in the turret or C.P., so that in surface control the speaker is on the P.C.O. group, and in barrage control on the A.D.O. group.

(d) Sub-division of the A.D.O. group is only necessary in ships which have an after A.D.P. The only ships where the after sub-group will include long-range A.A. armament are those in which the armament is four cornered, and the cruisers "Swiftsure," "Superb," "Ontario" and later.

(e) Arrangements have been made for the speakers to be put on new transferable mountings of medium calibre. This should also be done when sufficient spare cores are available in existing mountings.

(f) In later ships the armament broadcast will become one section of ship's main broadcast system with a lock-out switch in A.D.P.

(C22162) C

 

23E
 

8 C.A.F.O. P.84/47

APPENDIX V
REQUIREMENTS FOR A.I.D. IN DESTROYERS AND SMALL SHIPS

Position (as applicable) Pattern No.
Micro. Speaker.
Bracket Hand. Loud. Quiet.
1. Bridge 12607 - 12554 -
2. Crow's nest - 13321A 12554 -
3. After lookout - 13321A 12554 -
4. Captain's sea cabin - 13321A 12557 -
5. Ops. room or plot position 12607 - 8888A -
6. T.I.U. 12607 - - 12557
7. Main W/T - 13321A 8888A -
8. Each W. Radar position 12607 - - 12557
9. G. Radar position 12607 - - 12557
10. Each D/F position 12607 - - 12557
11. "Y" position (headache) 12607 - - 12557
12. Director - - - 12557
13. R/F director - - - 12608

Notes.-(i) In some ships the layout of the bridge may be such that two microphones are necessary and me than one loud speaker.

(ii) When D/F, W/T and "Y" offices are combined, one speaker will serve the whole compartment, but a microphone must be fitted within easy reach of each operator.

REQUIREMENTS FOR A.B.D.

Position (as applicable) Pattern No.
Micro. Speaker.
Bracket Hand. Loud. Quiet.
I. (a) Destroyers, fast minelayers, A.A. sloops:     
  Bridge, forward screen 12607 - - 12608
  Bridge, aft end - 13321A - 12608
Or    
(b) Destroyer leaders:    
  Bridge, port T.I. sight 12607 - - -
  Bridge, starboard T.I. sight 12607 - - -
2. T.I.U. 12607 - - -
3. Director 12607 - - 8888A
4. R/F director 12607 - - 12544
5. Adjacent torpedo tubes or approx. half-way along deck where tubes not fitted. (Aft conning position in fast minelayers) - 13321A - 12608
6. Aft bulkhead of aft superstructure - 13321A - -
7. T.S. - - - 8888A
8. Each M.A. gun mounting - - 12554 -
9. Each C.R. weapon or group - - 12554 -
10. Forward repair party - - 8888A -
11. Aft repair party - - 8888A -
12. Aft torpedo tubes (where fitted) - - 12554 -
13. Mining deck (fast minelayers only) - - 8888A -
14. Q.D. depth charges - - 12525 -
15. F.X. ahead throwing weapon - - 12554 -

Note.-Two microphones are required on the bridge in destroyers, leaders and fast minelayers In leaders, one should be fixed to each sided sight. In other ships one should be fixed to the fore end and one to the after end of the bridge

Requirements for A.B.D.

Against Position 7. T.S. in microphone column under "Hand" add "13321A (see note (ii))"

Add new note (ii) at bottom of page:-

"Note" (ii) Microphone pattern 13321A in the T.S. is only allowed to destroyers fitted with radar Type 275

(G 06873/52 A.F.O.P129/52.)

 

23F
 

9 C.A.F.O. P.84/47

Appendix V-continued

ACTION INTER-COM. SYSTEM (A.I.C.S.)

Position (as applicable) Pattern No.
Micro. Speaker.
Bracket Hand. Loud. Quiet.
1. Bridge:
Captain 12607 - 12554 -
P.C.O., port 12607 - - -
P.C.O., starboard 12607 - - -
2. Crow's nest - 13321A 12554 -
3. Aft lookout - 13321A 12554 -
4. Captain's sea cabin - 13321A 12557 -
5. Ops. room or plot position 12607 - 8888A -
6. Main W/T - 13321A 8888A -
7. Each W. Radar position 12607 - - 12557
8. G. Radar position 12607 - - 12557
9. Each D/F position 12607 - - 12557
10. "Y" position (headache) 12607 - - 12557
II. M.A. director 12607 - - 12557
12. T.S. - - 8888A -
13. Each M.A. gun - - 12554 -
14. Each group C.R. weapon - - 12554 -
15. Forward repair party - - 8888A -
16. Aft repair party - - 8888A -
17. Q.D. depth charges - - 12554 -
18. F.X. ahead weapons - - 12554 -
19. Aft conning position - - 12554 -
20. Each torpedo tube - - 12554 -
21. Aft bulkhead of aft superstructure - 13321A - -

Radar Reporting Line (Telephones).-Fitted to cover the following:-

(a) Warning Radar offices Mark X*** Pattern 12501.
(b) G. Radar ops. position Mark XI* Pattern 12622.
(c) Ops. room (at L.O.P.) plot position Mark X*** Pattern 12501.
(d) T.I.U. Mark XI Pattern 1193A.
(e) Compass platform Mark XI Pattern 1193A.

A call up system consisting of push and visual call is fitted at each of the first four positions above.

Note.-This will vary considerably with later ships.

 

23G
 

10 C.A.F.O. P.84/47

APPENDIX VI


T.I.U. TRANSMISSIONS

Typical arrangement for a Destroyer

Position. Transmission. Transmitter. Value. To.
T.I.U., Mark IIA
Section 1 Bearing (indicator) Magslip 360° Bofors director or S.T.A.A.G. mounting port.
Section 2 Bearing (power) Magslip 360° T.I. sight
Section 3 Bearing (indicator) Magslip 360° T.S. (T.C.U.) and M.A. director.
T.I. sight Bearing (indicator) Magslip 360° No. 3 section T.I.U.
M.A. director Bearing (indicator) Magsli p360° No. 2 section T.I.U.
Interrogator gear box (No. 2 section). Bearing "M" type 10' Interrogator aerial.
T.P.I. Bearing "M" type 10' Relative bearing scale.
T.I.U. Bearing "M" type 10' Ships head.
R.T.B. (R.T.U.53) Range. "M" type 0-10,000 (1) S.T.A.A.G. mounting, port.
Panel L.43 (R.T.F.) or Panel L.37 (R.T.B.). Range Magslip 0-36,000 T.S. (C.P.U.).

T.I.U. TRANSMISSIONS

Cruisers

Position. Transmission. Transmitter. Value. To.
T.I.U., Mark IIB
Section 1 Bearing (power)
Bearing (indicator)
3-in. magslip
2-in. magslip
360°
360°
After A.D.O. sight-port. (i) H.A.C.P., aft T.C.U.
(ii) H.A. director aft. (1) Free sight and (2) trainer.
(iii) "Y" barrage director.
(iv) No. 3 P.P. director via C.O.S. No. 4.
Section 2 Bearing (power)
Bearing (indicator)
3-in. magslip
2-in. magslip
360°
360°
Forward A.D.O. sight-port.
(i) H.A.C.P., port T.C.U.
(ii) H.A. director port. (1) Free sight and (2) trainer.
(iii) "A" and "B" barrage directors.
(iv) No. 2 P.P. director.
Section 3 Bearing (power)
Bearing (indicator)
3-in. magslip
2-in. magslip
360°
360°
P.C.O. sight, port or starboard via C.O.S.
T.S. bearing matching receiver.
Section 4 Bearing (power)
Bearing (indicator)
3-in. magslip
2-in. magslip
360°
360°
Forward A.D.O.-starboard.
(i) H.A.C.P., starboard T.C.U.
(ii) H.A. director starboard.
(III) "A" and "B" barrage directors.
(iv) No. I P.P. director.
Section 5 Bearing (power)
Bearing (indicator)
2-in. magslip 360° (i) H.A.C.P., aft T.C.U.
(ii) H.A. director aft. (1) Free sight and (2) trainer.
(iii) "Y" barrage director.
(iv) No. 3 and 4 P.P. director.
H.A. director port Bearing (indicator) 2-in. magslip 360° No. 2 section T.I.U.
H.A. director starboard Bearing (indicator) 2-in. magslip 360° No. 4 section T.I.U.
P.C.O. sight P. and S. Bearing (indicator) 2-in. magslip 360° No. 3 section T.I.U.
H.A. director aft Bearing (indicator) 2-in. magslip 360° No. 5
No. 1 section T.I.U}
Interrogator gear box (No. 3 section) Bearing "M" type 10' Interrogator aerial (relative)
T.P.1 Bearing "M" type 10' Relative bearing scale.
T.S. Bearing "M" type 10' Bearing matching receiver.
T.I.U. Bearing "M" type 10' Ships head
Filtered air plot Bearing "M" type 10' Dummy ship dial.
Panel L.37 (Sections 1 and 5 of T.I.U.) Range Magslip 0-36,000 Via C.O.S. to aft C.P. (C.P. (C.P.U. ))
Panel L.37 (Sections 2 Range and 4 of T.I.U.). Range Magslip 0-36,000 Port C.P. (C.P.U.).
Starboard C.P. (C.P.U.).

(C22162) 2,250+6 12/47

 

24
 

NOTES ON THE T.I.U. AUTO-ALIGNING GEAR

A noted on Plate I the aerial auto-aligning gear has been re-designed. The following notes give an outline description of the operation of the re-designed unit.

The auto-aligning gear consists of a pair of fast and slow contacts fitted in the local Aerial and Gyro Repeater of the controlling radar office (in later ships they will be fitted in the aerial control table) which are wired in parallel and arranged to break between 358 degs.-2 degs. of aerial gyro bearing, and a pair of fast and slow contacts fitted in the aerial hunter unit of the T.I.U. which are wired in series and arranged to make between 358 1/2 degs.-1 1/2 degs. of aerial gyro bearing. A fast contact (90 degs. per rev.) is necessary to get the quick and accurate break required. As it is only required to work once a revolution, a slow contact (360 degs. per rev.) also must be used. The relay is only energised when all four contacts are closed together.

These two sets of contacts are wired in series with the operating coils (connected in parallel) of three single line change over high speed relays. The common contacts of these relays are connected to the T.I.U. aerial hunter "M" type motor, which receives aerial gyro bearing when the relays are not energised, and a positive to No. 1 line and negatives to Nos. 2 and 3 lines when the relays are energised, thus magnetically locking the stator in its lining up position.

When the Aerial and Gyro Repeater contacts and T.I.U. aerial hunter unit contacts are in synchronism the operating circuit of the relays is open, as the contacts of the A.G.R. are open when the contacts in the T.I.U. aerial hunter are closed.

When the system is out of synchronism, the T.I.U. contacts will make when the A.G.R. contacts are still made, thus the relay,. operates holding the T.I.U. aerial hunter unit "M" type motor at 0 degs. It is magnetically locked at 0 degs. until the A.G.R. contacts break when the relay is released and the "M" type motor pulls into step with the aerial bearing transmission and continues to run in synchronism.

Mark XA "M" motors must be fitted (in lieu of a Mark X) in the A.G.R. and aerial hunter unit to ensure that they pull into the right step and also to give the extra torque and acceleration to the aerial hunter unit of T.I.U.

(C56071) E

 

PLATE 1 - The T.I.U. Box


PLATE 1a - SECTIONAL ELEVATION OF SECTOR SELECTOR UNIT AND INTERROGATOR GEAR BOX


PLATE 2 - THE T.I.U. PROJECTOR UNIT


PLATE 3 - CONNECTIONS TO THE T.I.U. AND T.P.I. AND CONTROL TABLE


PLATE 4 - VISUAL/RADAR TARGET INDICATION. TYPICAL COMMUNICATION LAYOUT FOR A FOUR-CORNERED SHIP


PLATE 5 - VISUAL/RADAR TARGET INDICATION. TYPICAL COMMUNICATION LAYOUT FOR A BATTLE CLASS DESTROYER


PLATE 6 - TYPICAL ARMAMENT BROADCAST SYSTEM FOR A CRUISER


PLATE 7 - THE UNIVERSAL SIGHT


PLATE 8 - METHOD OF DIS-ASSEMBLING T.I.U MARK II A AND B FOR TRANSPORTATION THROUGH A RESTRICTED SPACE


PLATE 9 - CIRCUIT DIAGRAM OF T.I.U.


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