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14
BOW AND STERN PLANES SYSTEMS
 
A. INTRODUCTION
 
14A1. General. Hydraulic power is used to tilt the bow and stern planes. Each system (bow and stern planes) has its own power supply system. Except in emergencies, the power facilities in each system are adequate for its own individual operation without reliance on power from the main hydraulic system.

The control units for diving and rising are assembled in a diving control stand located in the control room. There is a set of controls for stern plane tilting, a set for bow plane tilting, and control valves for bow plane rigging. The control panel has diving indicators, gages, and motor switches.

Three methods of plane tilting are available at the control panel, based on three different sources of hydraulic power. They are designated as follows:

1. Power, in which the power is independently developed in each plane

  tilting system by the motor-driven Waterbury A-end pump belonging to that system.

2. Hand, in which the power is developed in the diving control stand pump, connected to each system, by the manual efforts of the diving stand operator.

3. Emergency, in which the power is obtained from the main hydraulic system.

Emergency is used only when normal power fails. Hand power is employed when the other two power sources are, inoperative, or when silent operation of the submarine is necessary to avoid detection by the enemy.

In addition to bow and stern plane tilting, this chapter also contains a description of bow plane rigging. A schematic view of the bow and stern planes systems and their associated equipment is illustrated in FigureA-21.

 
B. BOW AND STERN DIVING GEAR
 
14B1. Bow planes. Each plane is carried on a separate stock. The mechanism for tilting planes consists of a hydraulic cylinder and piston arrangement connected by a connecting rod to the tiller, the latter being mounted on and secured by clamping and doweling to the hexagonal-shaped end of each plane stock. The planes are actuated between stops, allowing a total travel of 54 degrees of 27 degrees each side of zero tilt.

14B2. Stern planes. The horizontal athwartship for the stern diving planes is keyed to a tiller which is operated through an angle of 54 degrees by a connecting rod, cylinder, and piston arrangement located in the after torpedo room under the non-watertight walking flat.

The bow and stern diving gears are of the electrohydraulic type and under normal operation the planes are tilted by power. The

  hydraulic pump are the Waterbury type, size 5 A-end, connected by a flexible coupling to an electric motor of 7.1 hp at 350 rpm constant speed. These units are located in the forward and after torpedo rooms respectively.

The motor of the electrohydraulic system is started and stopped by a push button type switch, and provided with an electrically operated brake which grips the armature shaft when the motor is not being operated. An interlock switch, controlled by operation of the change valve at the operating station in the control room, prevents starting the motor except when the change valve is in Power position.

In the control room at the operating station, a handwheel is connected to another hydraulic pump. (See Figure 14-1.) Rotating the handwheel with the change valve set for Power forces oil to control cylinders at the electrically driven pump. This actuates the

 
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control shaft on the pump by means of a rocker shaft and bell crank, thereby controlling the direction of flow and quantity of oil. Thus, the direction and amount of tilt are governed by the rotation of the handwheel of the diving station; to the right for   Dive and to the left for Rise. The handwheel should always be brought back to its original position to stop further movement of planes; this also allows the centering device, consisting of a double-acting spring, to hold the pump control shaft in its neutral position.
 
C. OPERATIONS
 
14C1. Power tilting of planes. When tilting the bow or stern planes by power, the change valve for that plane must be in the power position. The stroke adjuster is set for one-quarter of a stroke and the hydraulic pump motor is started at the diving station. When the station is set for power tilting, turning the wheel delivers oil to the control cylinder which actuates the tilting box of the power-driven hydraulic pump. Tilting the box of a power-driven hydraulic pump causes it to deliver oil to the tilting ram.

When the wheel is turned clockwise, oil is delivered for dive angle on the planes; when the wheel is turned counterclockwise, oil is delivered for rise angle on the planes. (See FigureA-22.)

14C2. Hand tilting of planes. In tilting the bow and stern planes by hand, the electrohydraulic system is stopped and the change valve at the diving station is set for Hand; rotating the handwheel forces oil directly to the hydraulic cylinder located in the forward torpedo room for bow planes, and the after torpedo room for stern planes.

The bow plane setup is the same as the stern plane setup for hand tilting except that the hand rigging and tilting control valve is used on bow plane tilting to direct the oil to the rams (FigureA-23) when set in the tilt position.

14C3. Emergency tilting of planes. Provision is made for tilting the planes with the main hydraulic system by setting the change valve at the diving station in the Emergency position. The direction of oil flow for tilting the planes is then controlled by the emergency control valve.

The bow and stern planes have separate control valve handwheels for emergency operation. While the handwheels operate

  similarly, they are not interconnected and must be individually operated.

Turning the emergency control valve handwheel clockwise directs oil from the main hydraulic system directly to the stern plane ram in the after torpedo room and the bow plane rain in the forward torpedo room. The oil flow will be for dive. Turning the control valve handwheel counterclockwise admits oil to the stern plane ram and the bow plane ram for rise. (See FigureA-25.)

14C4. Plane angle indicating system. The plane angle indicating system is of the selsyn type. The bow plane transmitter is located in the forward torpedo room and is driven from the starboard plane stock by a gear segment and pinion. The stern plane transmitter is located in the after torpedo room and is driven by an arrangement of levers and links from the plane tilting piston rod. The indicators are mounted on the diving station panel in the control room, In addition, an auxiliary plane angle indicating system is provided which indicates the degree of rise or dive on the planes in 5-degree intervals. A mechanical plane angle indicator is provided in the forward torpedo room and two plane angle indicators in the after torpedo room, one on the after bulkhead and one at the tilting cylinder beneath the platform deck.

14C5. Stern diving gear and capstan motor. The stern plane tilting motor, located in the after torpedo room, is also used to operate the after capstan by a silent chain drive with the sprocket mounted between the motor and the hydraulic pump. The chain is removable and can be dissembled by removing a special pin from the links. The stern plane tilting hydraulic pump cannot be cut out when the capstan is in use; therefore, the pump control shaft should be in the neutral position to prevent the movement of the planes.

 
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Photo of Diving control station
Figure 14-1. Diving control station
 
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14C6. Stern plane drift stop. The position at which zero lift occurs with relation to the stern planes is with the planes set at 4 degrees in the rise, direction; the position at which minimum drag occurs is with the planes set at 2 1/2 degrees in the rise direction. Therefore, it is desirable that the indicator in the control room read zero when the planes are set at 4 degrees in the rise direction, because in that position the lift, when operating submerges, is zero. It is also desirable that when operating on the surface, the planes be set at that angle at which a minimum of drag or resistance is encountered. In order to obtain a setting of 2 1/2 degrees rise while operating on the surface, the indicator in the control room should read 1 1/2-degree dive.

When cruising on the surface under normal conditions, a drift stop is provided to prevent the stern planes from passing beyond the 2 1/2, degree rise position. This drift stop is located at about the midstroke of the end of the piston rod extension in the after torpedo room. A bar is provided to be lifted in the path of the end of the piston rod extension when the planes are approaching the 2 1/2-degree rise position blocking the path and thus preventing the rod extension from moving farther in the rise direction. The planes must be moved in the dive direction until the indicator (in the control room) reads at least 5 degrees dive before the stop bar can be lifted into position. A pin in the rod extension enters a hole in the bar as the planes are moved to the 2 1/2-degree rise position. The stop bar is released by moving the planes in the dive direction until the indicator (in the control room) reads at least 5 degrees dive, disengaging the pin from the stop bar and allowing the bar to drop clear of the path of extension rod.

14C7. Bow plane rigging arrangement. The bow planes are rigged out for tilting operation by the windlass and capstan hydraulic motor, a Waterbury size 10 B-end normally driven from the main hydraulic system through the rigging control valve. Provision is also made for rigging the planes by hand from the diving station by setting the change valve to Hand, the rigging control valve to Neutral, and the hand rigging and tilting

  control valve to rig. (See FigureA-24.) Rotating the bow diving handwheel to the right will rig out the planes. A hand-operated clutch is provided for windlass and capstan or plane rigging operation and is located in the forward torpedo room. With the clutch set for bow rigging operation, the hydraulic motor drives a vertical shaft through a reduction gear and worm gear arrangement. This shaft passes through the hull to the outside where bevel gears and shafting operate two pairs of 39 1/4-inch diameter spur gears. These gears are mounted in pairs athwartships and fore and aft, so that the forward and after gear of each pair carry at a point on the circumference the pin for the crank end of the plane rigging connecting rod. The gears are rotated 181 degrees 41" between mechanical stops when raising the planes from the horizontal to the housed position. At the lower end of the vertical shaft, an indicator switch is driven by bevel gears; this indicates the rigged in or rigged out position by telltale lights at the diving station.

14C8. Rigging and tilting interlocks. At the lower end of this same vertical shaft, the rigging interlock switch, driven by bevel gears, prevents the operation of the electrohydraulic bow plane tilting motor except when the planes are in the fully rigged-out position. There is also a hydraulic interlock valve which prevents the flow of oil to the plane tilting cylinder from the hand or emergency control valve until the planes are in the fully rigged-out position. The operating mechanism for this interlock valve is also driven by bevel gears from the vertical shaft, and the bow plane rigging indicator is mounted on the underside of the casing. If the sheer pin drive at the lower end of the pointer shaft fails, the interlock valve may be operated by applying the T-handled socket wrench to the squared lower end of the shaft extending through the pointer hub. This wrench is stowed on the underside of the worm gear unit adjacent to the valve operating mechanism.

In addition, there is also a regulating control valve operated from the same shaft. The purpose of this valve is to restrict the flow of oil to the hydraulic motor when the

 
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bow planes are nearly rigged out or nearly housed. The flow is not completely cut off; a small amount is bypassed to permit the planes to creep into the stops located on the large spur gears. There is also a lock on the rigging control valve operated by a solenoid; this prevents the housing of the bow planes unless the planes are within 1 1/2 degrees either side of zero tilt, and then only by manually operating the push button which releases the lock. An additional release of the solenoid lock is also provided for emergency use and is accomplished by means of a lever located in the armature end of the solenoid. This means of disengaging the solenoid lock should be used for rigging out planes only in   case they have been thrown off the position for rigging as a result of wave slap.

The diving gear control stations, bow and stern, are located together on the port side of the control room. (See Figure 14-1.) They are provided with an 8 1/2-inch depth gage reading to 450 feet and a rudder angle indicator. Each station is provided with an electrical self-illuminated selsyn type plane angle indicator, an auxiliary plane angle indicator reading at 5-degree intervals, a 16-inch depth gage reading to 165 feet, and a pair of spirit trim indicator inclinometers for angles from 0 degrees to 5 degrees and from 0 degrees to 15 degrees.

 
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Version 1.11, 16 July 2010