DESCRIPTION AND USE OF BLOCKS.
THE PLATES OF BLOCKS WILL, UPON REFERENCE, CLEARLY ELUCIDATE THIS TREATISE ON BLOCKMAKING.
BLOCKS are well known mechanical instruments, possessing the properties and powers of pullies. These powerful instruments have from 1 to 8 sheaves. The blocks in general use are, the single block, the double block, the treble block, and the fourfold block; but, when heavy weights or bodies are required to be raised or moved, blocks with a greater number of sheaves are applied, the increasing power being as two to one for every sheave moving with the object. Blocks differing from the common shape, are the bee-block, (which is made by the mast-maker,) the cheek-block, the long-tackle-block, the main-sheet-block, the monkey-block, the nine-pin-block, the rack-block, the shoe-block, the shoulder-block, the sister-block, the snatch-block, the strap-bound-block, the viol-block, and the warping-block. To the blocks may be added the dead eyes, hearts, parrels, trucks, uphroes, cleats, belaying-pins, toggles, thimbles, travellers, bull's eyes, &c. these being all furnished by block-makers.
The principal parts of blocks are their shells, sheaves, and pins, which are of various sizes and powers, according to the effect they are to produce.
The dimensions of the shells, and the thickness and number of the sheaves, are proportioned to the size of the ropes working in them, and the powers required: the sheaves turn abreast of each other in the shell, on one axis or pin, or one above another, on separate pins.
The shell is made of elm or ash, and hollowed between the cheeks, with one or more sheave-holes to receive the sheave or sheaves. On the outside of the cheeks of blocks that are to be strapped, one score is cut, towards the ends, in which part of the strap is buried; if they are double-strapped, they have two scores. A hole is bored through the centre to admit the pin; which, passing through both sides of the shell, forms the axis for the sheaves.
The sheave is a solid cylindrical wheel, and round its circumference is a groove one-third of the thickness of the sheave deep, in which the rope works. It is commonly made of lignum-vitae; but when for very laborious purposes, it is coaked in the middle with metal, or else made of cast metal: if the sheave is iron, it is coaked with brass, and if of brass, with the hardest bell-metal. The hole in the centre is something larger than the pin.
The pin is made of lignum-vitae, cocous, green-heart, or iron, and is the axis on which the sheaves turn.
DESCRIPTION OF THE TOOLS, AND EXPLANATION OF THE TERMS, USED IN
ARSE of a block. The end through which the fall reeves.
AUGER. An iron instrument to bore holes with; it consists of a shank, having at, one end a bit, and at the other end an eye to admit a handle, by which it is worked.
BEARDING. Reducing the thickness on the sides or edges.
BIT. An iron instrument resembling the shank of a gimblet, from 6 to 12 inches long, and from of 1/2 an inch to 1 inch diameter, and has at its end either a screw, a sharp point, or edge, to cut or bore holes with.
BOX of a rib-saw. Two thin iron plates fixed to a wooden handle; in one of the iron plates is an opening to receive a wedge, by which it is fixed to the saw.
BRAKE. An instrument to confine blocks while boring the hole through the sheave: it is formed of a piece of elm plank, 3 inches thick, about 13 inches broad, and 3 feet long, in which, near one end, are two pegs 2 inches and a half square fixed in mortise holes. Two inches from the side edge, towards the other end, is a double row of holes; to one of these holes a brake is attached by a wooden pin, which brake is 2 inches thick, 20 inches long, and 4 inches broad at one end, and tapering to a handle at the other. It is used as a lever, by pressing against it with the knee, and thereby confining the block.
BREAST of a block. The opposite end to that which reeves the fall.
BURR. A triangular hollow chissel, used to clear the corners of mortises.
CAP. A semi-circular projection from the sides and round-the end of a block above the pin; through it two holes are bored, obliquely from the sides, which meet and form an angle at the end; through these holes the strap is passed, to prevent its being chafed.
CHAMFERING. Taking off, or flatting sharp edges.
CENTRE-BIT. A bit, having in the middle of its end a small steel point, with a sharp edge on one side to cut horizontally, and a sharp tooth on the opposite side to cut vertically. Holes bored with this instrument are not liable to split.
CHEEKS of a block. The two sides of the shell.
CHISSELS. Sharp edged tools, made of iron and steel, of different lengths and breadths.
CHOCKS. Cylindrical pieces of wood or iron, screw-cut at one end, to screw into the end of a mandrel; some at the other end have a sort of peg to be driven into the work, which is retained by the assistance of an opposite centre: some chocks have, instead of a wooden peg, three pieces of iron in the end; this sort is chiefly used for broad thin work, without an opposite centre. Iron chocks are screw-cut, similar to wooden ones, and have a box at the end, into which the work is driven and retained with, or without, an opposite centre; in the sides of the box are holes to admit a punch, to punch out the work.
Explanation of the CONSTRUCTION & USE of the
Patent Blocks Mill
1 The horizontal horse wheel or great sweep is from 18 to 20 feet diameter. The upper surface is 9 or 10 Inches broad perfectly smooth and runs correctly horizontal.
2 The Vertical or Friction wheel. Of this there are two sorts double and single; the first runs with two leathers round its circumference giving motion to two lathes, or to a lathe and a saw frame and is thus constructed. Its centre consists of a solid cylinder of about 20 or 24 Inches diameter and 8 or 9 Inches long, with a surface perfectly smooth the extreme circumference of the wheel is from 3 to 4 feet diameter carries two leathers. by being hollowed towards the middle and rising towards the edges, thus [see above] by which the leathers running on opposite sides do not interfere with each other the pulley is about 5 Inches thick and about 3 Inches deep. The single wheel differs from the other only in the shape of the pully which has one curvature only thus [see above] and is about 3 Inches square The Axis of these wheels is of Steel, about one Inch diameter.
3 A square Iron box inclosing patent rollers on which the Axis of the friction wheel works. This box is fastened to
4 A frame of Oak the sides and ends of which are 6 Inches broad and 4 Inches deep the length of the frame in the clear is 6 feet, and its breadth about 15 Inches. This frame is fastened by hinges at one end, to a piece of Oak, fixed to the joist or floor; and is occasionally lifted by the lever removing thereby the friction wheel from being acted upon by the great sweep wheel.
5.5 Are the two levers used to lift the friction wheel from the great sweep by a cord from each lever to one lathe or to one saw frame. Thus when the workman wants to stop the machine, he pulls upon the cord and raising the friction wheel about one inch from the great sweep its motion ceases: And when he wishes to renew his work he lets the cord go, and immediately the two wheels coming into contact the motion is renewed.
One disadvantage attends the use of the double wheel, which is that its removal from the great sweep causes the two machines to rest.
6. Are the leather bands which pass round the friction wheel to the wheel of those Machines which are to be set in motion.
From the previous explanation of the construction its uses may be readily conceived five, six, or seven friction wheels may be adapted to the great sweep in proportion to its size, the power used to turn it and extent of the building containing it; and these wheels maybe double or single - The great ends to which this invention is applied is the cutting of sheaves by the saw frame; the turning of sheaves, pins &c. by the common lathes; & the boring of sheaves, blocks &c. by a lathe with a sliding puppet. It may be necessary here to explain the nature of the lathe with the sliding puppet & also the construction of the saw frame. This lathe differs from the common lathe in this. The puppet on which the work to be bored is fixed, is larger than ordinary, & slides on brass: it is pulled backward from the mandrel by a weight hanging through a sheave in the leg. There is likewise fixed in the sliding puppet two sheaves, and in the other leg two sheaves; through which a rope passes, having its standing part fixed to the leg, and when its fall is pulled on by the workman it presses the sliding puppet which has on it the sheave &c to be bored towards the bit in the mandrel; and when the hole is made, the workman lets go the rope & the weight draws back the puppet. The Saw frame is worked by the leather band going round the wheel 7 the parts of which marked 8 are boards 6 or 7 inches wide, which slide in & out being dovetailed. They are brought out to a little beyond the edge in order the keep the band from slipping off. The timber to be sawed is confined near the saw by chocks & a wedge; & at the other end by means of a screw which pressing down on it prevents its rising.
CLAVE. A stool 14 inches high, made of elm, and supported by 4 legs; the top 6 feet long, 2 or 3 feet wide, and 8 inches thick at each end, and only 4 inches thick in the middle, in which the shells are set up with wedges for making the sheave-holes.
CLENCH. To make a pin or bolt fast by battering and spreading the point.
COAKING OR BUSHING, is letting through the middle of a sheave a cylindrical piece of metal, with a hole through its centre, agreeably to the size of the pin that is to be admitted as an axis for the sheave to run on, &c. &c.
COUNTERSUNK. A hollow, cut by a bit round the edge of a hole.
COUNTERSUNK-BIT. A bit having two cutting edges at the end, reversed to each other, which form an angle from the point.
DRAWING KNIFE. An instrument made of a piece of steel, 2 inches wide, and 20 inches long; the ends are drawn out fine, bent, and fixed in wooden handles; it is ground to a sharp edge, and is sometimes used instead of the stock-sheave, to pare off the rough wood.
FALL. The rope that with the blocks composes a tackle.
FORELOCK. A small wedge of iron driven through a hole near the end of iron pins to keep them from working out.
FRAME-SAW, for two persons to saw with, has an iron bow over the back confined at the ends by rivets: some are set in motion by a mill, and have wooden frames.
FUTTOCK PLATE, is of iron; the upper part of it is open like a ring, to fix the dead eye in, and a round hole is punched in the lower end of the plate for the futtock-shrouds to hook in, or a bolt to be driven through when used for the lower shrouds.
GAUGE. A wooden instrument to mark off distances, is a square stick 9 inches long, with an iron tooth through one end; this stick slides through a mortise in the middle of a semi-circular piece of wood that serves as a stop, the stick being moved at pleasure.
GOUGES are long, sharp, circular-edged tools, similar to chissels. Gouges and flat tools, used in turning, are stouter and longer than those used with a mallet.
GOUGE-BIT. A bit smaller than a centre-bit, with a hollow edge at its end like a gouge.
GREEN-HEART, a wood imported from the West-Indies, used for the pins of blocks.
HOLDFASTS to confine the work on the holdfast-bench, are made of iron from 15 to 30 inches long, and from half an inch to one inch and a half diameter: this iron is bent at one-third the length, and forms nearly a square; the longest part is round, and is called the foot; the shortest part is flattened in the inside, and is called the head: to confine the work it is put through a hole in the bench.
HOLDFAST-BENCH. A bench of elm plank; its top is 4 feet long, 12 inches wide, and 3 inches thick, with 4 legs 20 inches long; within 4 inches of one end are two upright pieces, 3 inches square, fixed in mortises; and along the middle of the bench are two rows of holes, in which the holdfast is jambed to confine the work that is to be sawed or trimmed.
JAMBED. Set fast with wedges.
LASHING. The rope lashed to a block for securing it to any object.
MANDREL of the turning lathe. An iron spindle, with a screw-cut box at one end, to screw the chock in which confines the work; round the middle of the spindle is a collar with a groove, in which the cord works that turns it. It is used in a lathe that is worked by a wheel instead of a treddle.
MILL. A patent invention used by some block-makers; it consists of a large horizontal wheel, turned by horses, which, by means of other wheels, iron cranks, leather bands, &c. gives motion to different turning-lathes and frame-saws, that cut the sheaves, and turn the sheaves and pins. The plate of this mill more fully describes its construction and use.
NOSE-BIT. A bit similar to a gouge bit, having a cutting edge on one side of the end.
RASP. A sort of rough file made of steel, with short sharp teeth upon it. It is fixed in a wooden handle, and is used to rub down the edges of the shells of blocks, &c.
REAMING. Encreasing the size of a hole by a larger instrument.
RIB-SAW is a long narrow saw used in a pit.
ROLLER, a cylindrical pin turning on its own axis, and is used in some blocks instead of a sheave.
Patent rollers are made of two parallel circular plates of brass, about 1/4 inch thick. Four or more solid brass cylinders are placed at equal distances round these plates, and work upon their own axis, between them, at right angles. Thus any pin working through these plates of brass must touch the rolling surfaces of the solid brass cylinders, by which the friction is considerably lessened.
SADDLE, is that part of a monkey-block which is hollowed out to fit the convexity of the yard, to which it is nailed.
SCORE. A notch or hollow cut by a saw, gouge, or chissel.
SHACKLE. A semi-circular ring of iron, with a hole in each end for a ring or bolt of iron to pass through, and is used to hook or lash a tackle, &c. to.
SHOULDER. A projection made upon the surface of blocks, pins, &c. by reducing one part to a less substance.
SPOKE-SHAVE, a kind of plane to smooth and finish the shells, is a piece of steel, 4 or more inches long, and one inch 1/2 broad; sharp at one edge as a knife, and 1/4 of an inch thick at the back: at each end is left about 2 inches of narrow steel, bent up as pegs, by which it is regulated and secured in a piece of wood 10 inches long, and narrowed at each end, for handles.
STOCK. A wooden instrument to bore holes with, by fixing a bit in the lower end, and a pin with a round head in the other end; the pin and the bit serving as an axis to turn it on.
STOCK-SHAVE. A large sharp-edged cutting knife, with a handle at one end and a hook at the other, by which it hooks in an iron staple that is driven in an elm block; it is used to pare off the rough wood from the shells of blocks, &c.
STRAP. The circular binding of rope or iron surrounding a block, by which it is fastened with a hook or lashing to any place.
SWIVEL, any thing which is fixed into another body, in which it turns round.
SWIVEL-HOOK. A hook that turns in the end of an iron block-strap, for the ready taking the turns out of a tackle.
TOGGLE-BOLT. A small iron bolt, having a flat square head, with a hole or eye punched through.
TREDDLE. Two thin battens 4 feet long, laid transversely under the lathe; to the lower batten the cord is fastened that connects it to the lathe, and the work is put in motion by the pressure of the workman's foot: the upper batten is fixed at one end to the ground with a thick piece of leather, resembling a hinge, and at the other end across the under one by an iron pin, for which purpose 8 or 10 holes are bored along the middle to regulate it to the work.
TURNING-LATHE, a well known machine for turning sheaves, pins, &c. is composed of two legs 34 inches high, and on each side their upper ends is fastened a piece of oak, called cheeks, about 8 feet long and inches square, and about 3 inches asunder; between which slide two pieces of wood called puppets, that are made to fasten at any distance the work may require, by a wedge driven through them under the cheeks. Near the upper part of one is fixed a strong sharp spike of tempered steel,
and opposite to it in the other is a sharp-pointed iron screw; between these the work is sustained and kept in a circular motion, by means of a cord turned round it, and fastened above to a pliable pole, and underneath to a treddle moved by the foot: against the sides of the puppets is confined a batten, with a pin through one end, called a rest, for the workman to keep his tool in a steady position on. When the work is too heavy for the treddle to perform, a wheel is substituted, which is turned by one or two handles, and is connected by means of a cord, the ends of which are spliced together, and fixed in a groove round the wheel, then crossed and put round a groove in the collar of the mandrel: to be turned with a swift and regular motion.
WEB. The thin partition on the inside of the rim, and between the spokes of an iron sheave.
THE PRACTICE OF BLOCK-MAKING.
THE proportions for single, double, treble, fourfold, and other blocks, are as follow; viz. the length is 8 times the breadth of the sheave-hole, which is one-sixteenth of an inch more than the thickness of the sheave; the thickness of the sheave is one-tenth more than the diameter of the rope it is intended for, and the diameter of the sheave is five times the thickness. The breadth of the block to be six times the thickness of the sheave, and the thickness to be one half the length, or nearly so.
Flat thin blocks are three-eighths of the length thick; but all blocks, having more than one sheave, encrease their thickness more than the above proportion, by the additional number of sheave-holes, and middle-parts or partitions; the thickness of each partition to be one-sixth less than the breadth of the sheave-hole. These are the general dimensions, but sometimes vary, according to the use intended for.
Very large treble and fourfold blocks are formed of separate pieces, as the cheeks, middle-parts, or partitions, &c. when thus made, they are termed made-blocks.
The shells of blocks are first sawed to their length, breadth, and thickness; and the corners or angles are taken off. They are then delivered to the workman, who first gauges the size of the sheavehole in the middle, one-sixteenth larger than the thickness of the sheave, and once the thickness longer than the diameter, for a single sheaved block. In blocks of two sheaves, the middle-part or partition is kept in the middle, and is one-sixth less than the sheave-hole; each sheave-hole is gauged equally on each side, and so for all blocks with a greater number of sheaves.
The blocks are then jambed up edgeways with wedges in a clave, and the sheave-holes are made thus: the length and breadth are first gouged out, and holes then bored half way through the block, along the part gouged out, with an auger the size of the sheave-hole; the opposite side is then set up, and the sheave-hole gouged and bored in the same manner, to meet the holes on the opposite side. Blocks from 10 inches and upwards have one hole bored at each end, and cut through with a chissel; and the wood is sawed out with a rib-saw. All blocks have the sheave-holes cleared through by chissels; and by burrs at the corners.
Blocks, to have iron straps, should have the strap fitted on before the wood is cut out of the middle.
The hole for the pin is bored through the middle of the block, one-tenth less than the diameter of the pin. It is the practice of many block-makers to bore it after the sheave-hole is cut, but it is better to bore it through the solid.
The outsides and edges of the shell are next rounded off by the stock-shave, and neatly finished by the spoke-shave: as the neatness of the finishing depends upon the use the block is designed for, it rests on the judgement of the workman. In the royal-navy, blocks are left thick upon the edges of the cheeks, but in the merchant-ships, the edges are sometimes thinned off to a small square, and sometimes rounded off.
The scores for the straps are gouged out along the outsides of the cheeks, and taper in depth, from nothing at the pin to half the thickness of the strap at the ends of the block, for a single score; and the same on each side of the pin for a double score. The scores are gouged down, across the breast of the block, to half the size of the strap, to allow for the serving.
STRAPPING. A seventeen-inch block has a five-inch rope strap, and every inch in length above or under, to a 12 inch block, has half an inch more or less fixed rope allowed for the strap; an 11-inch block has a 3-inch strap; a 10 and 9 inch block, 2 inches and a half; an 8 and 7 inch block, 2 inches; a 6-inch block, one inch and a half; a 5-inch block, 1 inch; and a 4-inch block, three-quarters of an inch.
The score round iron-bound blocks is taken out to the size of the iron strap, sufficient to bury it, except at the pin.
Iron straps are from one-quarter to one inch in thickness, and nearly three times the thickness in breadth: the thickness of iron straps should be proportioned to the strain they are to resist. The cat-block must have a strong strap and large iron hook, which hooks the ring of the anchor in catting. The top-block a stout iron binding, with a strong short hook. Top tackle-blocks have strong iron bindings, the upper block with a tackle-hook, and the lower block with a swivel-hook.
The swivel, in iron-bound blocks, is to turn it occasionally, to untwist the parts of the rope that form the tackle, as the mechanical power is greatly reduced thereby.
The sheaves, after the score is cut, are fitted: they are solid cylindrical wheels, commonly made of lignum-vitae, one-tenth thicker than the diameter of the rope intended to run on them, and five times that thickness in diameter; they are sawed from the bough or trunk of lignum-vitae, which must be matched as near the size as possible, for, set the diameter of the piece be what it may, it will make but one sheave, as the heart must be kept near the centre: the sheaves are cut by hand with a frame-saw, or by a mill, and often at the pit by a pit saw. The hole for the pin should be bored through the centre by a bitt fixed in the mandrel of a turning lathe, or with a stock and bitt, and reamed with an auger one-sixteenth larger than the diameter of the pin, that it may turn easily; they are then put in a lathe and turned smooth, and the outer circumference hollowed one-third of its thickness, that the rope may embrace it closely.
Sheaves for very laborious purposes are made of cast metal, coaked in the middle with hard bell-metal; some are made of brass only, others of iron, with a brass coak, either open or webbed; and lignum-vitae sheaves are often coaked, or plated, to make them wear longer and work better.
Coaking or bushing is letting through the middle of a sheave a cylindrical piece of metal, with a hole through its centre, to admit the pin or axis on which the sheave turns; on each side of the sheave a plate is set in, having 3 or 4 corresponding holes in each, for rivets to go through, to secure and strengthen the whole. The entrance of the hole; in the plates are enlarged, that the heads of the
rivets and points when clenched may have a smooth surface. When but one plate, the rivets have broad heads; the holes in the sheave are made accordingly, and the points are clenched on the plate.
The cylinder and one plate are cast in one piece.
PLANK COAKING is letting in narrow pieces of lignum-vitae, transversely to each other, one on each side of the sheave; which has likewise a small circular brass plate set in on each side, and rivetted through, as others.
PINS OF BLOCKS are made of lignum-vitae, or cocus; and some times, for common blocks, of green-heart, a wood which is imported from the West-Indies: the diameter of the pin is the thickness of the sheave, and is turned in a lathe, except the head, which is left eight-square, to prevent its turning in the block, and is driven through the holes in the block and sheaves. Brass, iron, and lignum-vitae sheaves, that are coaked or plated, have iron-turned pins, with square heads, and sometimes a hole in the point, for a forelock, to prevent their coming out.
After the sheaves are fitted, the inside of the sheave-hole, at the arse of the block, is gouged hollow, to admit the rope, and answer with the sheave; and a small neat chamfer taken off the edges.
MADE-BLOCKS have the shell made of several pieces of elm plank, suited to the thickness of the cheeks, sheave-holes, and middle-parts, and are strongly bolted together with three bolts, at each end, driven through and clenched on a ring at the points. These blocks have flatter cheeks and squarer edges than other treble and fourfold blocks. Of this sort are large, treble, and fourfold blocks, for heaving down ships or other heavy purchases.
Smaller made blocks, of modern invention, are made of two pieces, joining in the middle, and the pin to work on patent rollers, set into the inside of the cheeks, which are bolted or rivetted together at the ends. These blocks are thought too complex for the royal-navy, and not so easily remedied in case of failure.
Altho' the shells of different blocks vary in shape, the outsides are finished in a similar manner.
BEE-BLOCKS are made of elm; in length, seven-ninths the length of the bee; the depth, two inches for every foot in length; and seven-eighths that depth is the thickness. It is trimmed square, chamfered on the outside edges, and fitted with a sheave in one end: a hole is cut in the other end, to be fitted with a sheave, should the other fail.
The sheave-hole is two-sevenths of the length of the block, and one-fourth the length of the sheave-hole in breadth, and half the length of the sheave-hole within the end.
Bee-blocks are bolted to the outer ends of bow sprits, under the bees, and the bolts serve as the axis or pin for the sheaves to work on; the fore-topmast-stay reeves through the sheave-hole at the foremost end of the starboard bee-block, and the fore-topmast-preventer, or spring-stay, through the sheave-hole at the after end of the larboard bee-block.
CHEEK-BLOCKS, or half-blocks, are made of elm plank; the length is twice and a half the depth of the topmast-head; the breadth is seven-eighths of the depth of the topmast-head; and the thickness half the depth of the topmast-head. The depth of each tenon and thickness of the cheek, when the sheave-hole is cut, is each three-eighths of the whole thickness, consequently the remaining 2/8 is the sheave-hole. The three tenons to be each two inches square, one in the middle, and one at each end, and the length of the holes to be the thickness of the sheave more than the breadth of the block. The back of the block is divided into three parts, and one-third on each side is bearded down to one-third the thickness of the cheek on each edge. Pins of iron are made suitably to fasten them to the topmast-head, and the sheave-holes are coppered, for durability. Cheek-blocks are bolted to the 'thwartship sides of topmast-heads, close up under the cap: the bolts serve as the pin or axis for the sheaves
to work on; the jib-stay and haliards, and fore-topmast-staysail-stay and haliards, reeve through the cheek-blocks at the fore-topmast-head, and the main-topmast-staysail haliards, and middle-staysail-stay and haliards, reeve through the cheek-blocks, at the main-topmast-head.
DEEP-SEA-LINE-BLOCKS are the same as a wooden snatch-block, only smaller; generally from 9 to 11 inches long.
D-BLOCKS are lumps of oak in the shape of a D, from 12 to 16 inches long, and 8 or 10 inches wide. They are thirded and bearded on the back, and the edges beaded. A sheave-hole is cut through the middle fore and aft. It is bolted to the ship's side, in the channels, to reeve the lifts, &c.
LONG-TACKLE-BLOCK. The shell is made of ash or elm, two-thirds longer than the proportion for a single block; as it is similar to two single blocks joined together endways; one to be two-thirds less than the other. They are used for tackles, and are made agreeably to the size of the rope, as other single blocks. They are used in the royal-navy, and East-India service, as yard-tackles; but in the merchant-service, as loading-tackles.
MAIN-SHEET-BLOCK. The shell is made of ash or elm, one-half longer than the proportion for single or double blocks; the additional length is tapered, and a hole bored through between the sheaves and the end, to admit the strap: the length of the pin is the length of the block, and is similar to a belaying-pin, as it is sometimes used for that purpose. They are used for the sheet-tackle of small vessels mainsail-booms; are single or double, and the sheet or fall is always belayed round the pin.
MONKEY-BLOCKS. The shells are made of ash or elm; some are only small single blocks, attached by a strap and iron-swivel to iron straps that embrace and nail to the yard, the block turning to lead the small running ropes in any direction. Others are nearly eight-square, with a roller working in the middle, the same as a sheave, with a wooden saddle beneath, to fit and nail to the yard.
This sort of blocks is sometimes used on the lower yards of small merchant-ships, to lead (into the mast or down upon deck) the running rigging belonging to the sails.
NINE-PIN-BLOCKS. The shells are made of ash or elm, and resemble the shape of a nine-pin, though flatted on the sides: their lengths are generally confined to the place they are fixed in, which is mostly under the cross-pieces of the forecastle and quarter-deck bitts. The breadth of the block, sheave, &c. is governed by the rope, as the single block, and tapers at the ends to three-eighths of the breadth of the middle: the pin at each end, which serves as a vertical axis, is two-thirds the bigness of the end. The thickness is 5-8ths the breadth. These blocks may be turned in a lathe, and flatted with a spoke-shave afterwards. They are used to lead the running ropes in a horizontal direction.
QUARTER-BLOCK. See thick-and-thin block.
RACK-BLOCKS are a range of small single blocks, made from one solid, by the same proportions as single-blocks, with ends, in form of a dove's tail, for the lashing, by which they are fastened athwart the bowsprit, to lead in the running ropes. They are seldom used.
SHOE-BLOCKS are two single blocks, cut in a solid piece, transversely to each other. They are used for legs and sails of the buntlines, but are seldom used.
SHOULDER-BLOCK is a large single block, left nearly square at the lower end, or arse of the block, and cut sloping in the direction of the sheave. Shoulder-blocks are used on the lower yardarms, to lead in the topsail-sheets; and, on the topsail-yards, to lead in the topgallant-sheets; and by means of the shoulder are kept upright, and prevent the sheets jambing between the block and the yard: they are also used at the outer end of the boomkins, to lead in the fore-tacks.
SISTER-BLOCKS are made of ash, similar to two single blocks, and are turned out of a solid piece, about 20 inches long, one above the other; between the blocks is a score for a middle seizing:
a round head is turned at each end, and hollowed underneath, to contain the end seizings; along the sides, through which the pins are driven, is a groove, large enough to receive part of the topmast-shroud, in which it is seized. In these blocks reeve the lifts, and reef-tackle-pendents, of the topsail-yards.
SNATCH-BLOCKS are proportioned by the rope, as a single block, leaving twice the length for the score and lashing; they taper from the sheave to the lashing-end, to half the breadth and thickness at the sheave: one side of the shell is cut across above the sheave, large enough to admit the rope or fall. In the royal-navy, snatch-blocks are iron-bound, terminating at the small end with a swivel-hook, or an eye, large enough to receive several turns of lashing; that part of the strap, over the notch in the side, lifts up with a hinge, and is confined down, when the rope is in the block, by a small iron hook, or latch, that hooks in the eye of a toggle-bolt, and that secures the upper end of the strap: the hinged part of the strap goes over the bolt, with a hole in the end; the strap is set into the block its thickness, and is confined by the pin and nails: they are used for heavy purchases, and when a warp, or hawser is brought to the capstern. Snatch-blocks, not iron-bound, have a large hole bored through the tapering end of the shell, for the lashing. They are used for the main and fore sheet blocks of square-rigged vessels.
STRAP-BOUND-BLOCKS are single blocks, with a shoulder left on each side, at the upper part, to admit the strap through, a little above the pin. These blocks are used at the clues of the squaresails, for the clue-garnets or clue-lines, and under the yards; the shoulder saves the strap from chafing.
THICK-AND-THIN, OR QUARTER BLOCK, is a double block, with one sheave thicker than the other, and is used to lead down the topsail-sheets and clue-lines. In the merchant-service they are used single, thick and thin.
VOYOL or VIOL BLOCK is a large single-sheaved block; the length is 10 times the thickness of the sheave-hole, which is three-eighths more than the thickness of the sheave; the thickness of the sheave is one-tenth more than the diameter of the viol, and the diameter of the sheave is seven times the thickness. The breadth of the block to be 8 times the thickness of the sheave, and the thickness to be two-sevenths of the length. This block is double scored, the sheave is coaked with brass and the pin is iron, and near the thickness of the sheave. It is used in heaving up the anchor. The viol passes round the jear-capstern, and through the block, which is lashed to the main-mast; and the cable is fastened in a temporary manner to the viol in several places. It is seldom used but in the largest ships in the royal-navy.
WARPING-BLOCK is made of ash or elm board, shaped similar to the body of a bellows: the sides or cheeks are 8 inches and a half broad in the middle, and tapered to 2 inches broad at the ends; the back, or longest cheek, to be 16 inches long, and seven-eighths of an inch thick, with a hole bored through the upper end to receive a leather strap; the upper cheek is 12 inches long, and seven-eighths of an inch thick, except the lower end, which is one inch and seven-eighths thick, and forms the sheave-hole. The sheave is one inch and a quarter thick, and seven inches and a half diameter, made of lignum-vitae, coaked with brass; it is set into the cheeks one-eighth of an inch, to prevent the yarn getting between the sheave and cheeks. The cheeks are fastened together at the lower end with three screws and nuts; and the pin, which is iron, is 7 inches long, driven through the middle of the block, with a shoulder on the upper side, and clenched at the point on the lower side of the shell: the upper part of the pin is tapered small, and a wooden handle rivetted thereon. The cheeks have a broad chamfer round the outer edges; the inside edges, and inside of the block above the sheave, are lined with thin iron, neatly screwed on, to prevent the block wearing. This block is finished in a
neater manner than blocks in general, and is seldom used but by rope-makers, to warp off the yarn into hauls for tarring.
BESIDES BLOCKS, THE FOLLOWING ARTICLES ARE GENERALLY FURNISHED BY BLOCK-MAKERS.
DEAD-EYES are blocks made of elm, without sheaves, from 4 to 30 inches diameter, and are in thickness one inch more than half their diameter. Through the flatted sides, one-fourth the diameter within the circumference, are bored three holes, which form a triangle, large enough to reeve the laniard. The single hole is placed furthest from the resistance, and the edges of the holes, nearest the resistance, are gouged or sunk in, to ease the strain.
A score is gouged round the middle of the outside of the dead-eye, large enough to receive half the stay, shroud, or iron-binding, which is connected to the links.
Dead-eyes, for tops, are fixed in the futtock plates, and used by some merchant ships for the lower shrouds.
Dead-eyes are used when the strain is too great to trust a pin and sheaves. Spare dead-eyes are iron-bound, with an eye, for the ready hooking, in time of necessity, to an iron ess-hook.
HEARTS. A peculiar sort of dead-eye, made of elm, from 4 to 40 inches in diameter, shaped to resemble a heart, and flatted on the sides, through which are gouged a large hole to contain the laniard, that extends the stay; the larger the hole the better; so that one-third the diameter is left nearest the strain, decreasing on the sides and opposite part: four or more grooves are gouged at the edges of the hole, on the broaden part, to receive the first turns of the laniard, and ease the strain: round the outer circumference is gouged a groove, in the middle, to receive the stay.
Sometimes hearts are used instead of dead-eyes, for setting up shrouds.
BULLS-EYES are a sort of small oval blocks, without sheaves, made of hard wood. They are turned in a lathe; have a groove round the outside, and an oval hole gouged through the middle. They are used instead of blocks and iron thimbles, but very seldom used at all.
PARRALS. An assemblage of ribs and trucks, which, with the parral rope, form a collar, to attach the upper yards to the masts, so that the yard may slide easily up or down the mast.
The rib is made of ash board, the diameter of the yard in length and one-third the length in breadth. It is straight on the inner edge, and divided into two semi-circles on the back, with a hollow cavity between. Through the flat sides are bored two holes, one in the middle of each semi-circle.
The truck is made of ash, or harder wood, the breadth of the rib in diameter, and one-third more than the diameter in length: it is turned in a lathe; and through the centre, lengthways, is bored a hole to answer those in the rib.
Some parrals consist of trucks and a parral-rope only. They are globular, with a hole through the centre for the rope.
TRUCKS. Shroud-trucks are short cylindrical pieces of ash, or harder wood, turned in a lathe, and a little rounded on the edges, with a hole bored through the centre lengthways, and a groove gouged on the outside in the same direction, to suit the shroud or rope intended to be seized to: round the middle, or at each end, is a score, (turned) for several turns of seizing to lie in; some are wooden balls, with a hole through the middle, and grooved round the outsides for the seizing to lie in. Trucks for the upper part of mast-heads, or flag-staffs, are made of elm, the size of the top-mast in diameter, and one-sixth the diameter in thickness: they are turned in a lathe, and reduced to three-fourths of the thickness at the edge; have a square mortise cut through the middle, to suit the head or masts or staffs, and a small sheave-hole cut through on each side of the mortise, for the flag or other haliards.
Trucks, in the royal-navy, have small brass sheaves and pins. In the merchant-service, they have only two holes bored through, to reeve the haliards, which traverses over a rounded piece of wood, nailed across the truck, on the upperside.
Ornamental trucks, for vanes, are turned in a lathe, mostly shaped like acorns, with a hole bored up the centre, by which they are fixed, and terminate the end of the spindle, and prevent the vane stock's rising. Other trucks, for this purpose, are longer, and taper more to a point, according to fancy.
UPHROES are oblong blocks, made of ash, without sheaves, from 9 to 30 inches long, and 2 to 5 inches diameter; having several holes bored through the middle at equal distances, and grooved round the outside, to receive the rope by which it is suspended.
They are used to suspend the awnings, by extending the small ropes equally, through the holes lengthways, along the middle of the awning: formerly used as a fence under the brim of tops, to prevent the foot of the topsail chafing, but are seldom used now for this purpose, except in small vessels.
CLEATS are made of oak plank, or board, sawed to the different shapes for the use designed and then made smooth, and finished with gouges, chissels, and rasps. The largest are called RANGES, or RANGE-CLEATS, for belaying tacks and sheets to: they are from 3 to 7 inches thick, and seven times the thickness in length. The arms are each one-third of the length, and made round; the middle, between the two arms, is left square twice the thickness in breadth, through which it is bolted, or fastened; the back is curved in the length, that the arms may rise from the inside straight. BELAYING-CLEATS are shaped the same as range-cleats, but are smaller. SHROUD-CLEATS are similar to belaying-cleats, with the addition of an inside piece, out of the same solid, long enough to have a score on each side of the middle part of the cleat, to contain the seizings which fasten it to the shroud; the inside is hollowed to fit the shroud, and another score cut across the middle of the cleat for the middle seizing
the scores are rounded on the outside edges, and cut deep enough to bury the seizing, to prevent its being worn when the rope is belayed.
SLING-CLEATS are made of elm plank, in length once and a quarter the diameter of the yard, in breadth one-fourth the length, and thickness two-thirds the breadth. The shoulder to be one-third the length of the cleat, and hollowed on the back from the shoulder to the end: are used as stops to the straps of jeer-blocks, &c. to the lower yards.
THUMB-CLEATS are similar to arm-cleats in shape, but smaller, and are nailed up vertically, to hang any thing on; or horizontally, as stop-cleats.
STOP-CLEATS are made of oak plank, or board, of all lengths under 12 inches; the largest are commonly for gammoning bowsprits and stops to stay collars. The breadth to be one-fourth the length; the thickness to be two-thirds the breadth; and hollowed on the back. Those for lashings at the mast-heads are made of elm, three times the thickness in breadth, and once and a half the breadth in length.
COMB-CLEATS are made of ash, or elm board, have one or more hollow cavities gouged in the middle, and the backs rounded to resemble a cock's comb.
COMMON-CLEATS are of elm, sawed tapering on one side; are about 3 inches thick, 4 inches broad, and 12 inches long.
WEDGES are made by an axe, or engine, of oak or beech, and are similar to common cleats, but taper on both sides.
BELAYING-PINS are wooden pins, turned in a lathe, made of ash, 16 inches long, one inch and three-eighths diameter at the upper end, which is turned as a handle; is three-sevenths the length, then shouldered in to one inch and an eighth diameter.
RACK. A narrow oak board, or rail, containing a number of belaying-pins, which are used to belay small running rigging to: some belaying-pins are made of iron, and taper each way from the middle, and are driven into racks, boatskids, or rails.
TOGGLES are turned in a lathe: those for confining the straps of large blocks, as the winding or the fish-tackle-blocks, are large tapering ash or oak pins, from 18 inches to 3 feet long, and one-fifth the length in diameter. Small toggles are little wooden pins, 3 to 9 inches Long, and taper each way from the middle, round which is a notch, whereby they are seized to the top-mast cross-trees, or elsewhere about the rigging.
THIMBLES are circles of iron, made by smiths, from 1 to 4. inches diameter; the edges are turned outwards, and form a groove, to contain a rope on the circumference.
TRAVELLERS are circles of iron, made by smiths, similar to thimbles, but larger, and much lighter: they are to facilitate the descent of topgallant-yards by the backstays, &c. Jib-traveller is an iron ring, five-eighths to one inch and a half thick, and the diameter once and a quarter the diameter of the jib-boom, with a hook and shackle that slide on the ring.
HANKS are made of narrow hoops, or tough wood, bent round and confined at the ends by notches: they are to hasten the descent of staysails, being fixed on the stay, and the head of the sail bent to the hanks. There are iron hanks similar in shape to the former, but open at the lower part, to go over the stay; made broader in the middle than at the ends, which causes them to spring to their shape; the ends are drawn out fine, and turned into a small ring, for securing the head of the sail by the seizing. Iron hanks are mostly to the foresails of vessels with one mast.
IRON HOOKS, for tackles, are made with an eye to receive the thimble, and taper at the point: they are hollow on the back, that a seizing may lie on them, without slipping; or a catspaw hitch: a hole is generally punched through the point, for mousing. Iron hooks, for the futtock-shrouds, have a square point, to prevent their unhooking.
FIDS are tapered pins, made of wood or iron; the wood are turned in a lathe. SPLICINGS-FIDS are made of cocus, and are used for strapping blocks, and splicing the running rigging. SETTING-FIDS made of ash, are used for setting blocks in the straps. CABLE and STAY-FIDS, made of elm, used in splicing stays and cables. Those made of iron are short and thick, sometimes having an eye in the largest end, and are commonly curved near the point.
MARLINE-SPIKE is made of iron, smaller than a fid, with a round knob at the head, and is used as the splicing-fid.
MALLETS are cylindrical pieces of wood, with a wooden handle fixed in the centre, and are made of ash or other hard wood; used for driving on the heads of chissels or gouges. SERVING-MALLETS, have a score gouged out along the side, for serving of ropes. DRIVING-MALLETS, or COMMANDERS, are about 20 inches long, and 8 or 10 inches diameter, with a handle 3 times the diameter in length: used for driving in large fids, and to beat up the fall round a capstern.
CHOCK. A square tapering piece of elm; it is one-fourth longer than the size of the base, or butt end, with a hole bored through the sides: used in strapping large blocks.
SERVING BOARD is a tapering thin piece of board, with a small score gouged at the end and sides. It is used for serving small ropes.
SHOES FOR ANCHORS are oval pieces of elm plank, about 2 feet long, sawed out, and rounded on the underside with an adze: in the middle of the upperside a double score is taken out with a chissel, 2 inches broad; sunk three-fourths of an inch each way from the middle, that it may catch the bill in either direction: at the small end is bored a hole for a laniard. It is placed under the bill of the anchor, when removed from one place to another, to prevent its tearing the ships sides or deck.