A Treatise on Marine Architecture. Peter Hedderwick Windlass ... Lars Bruzelius Lars Bruzelius 1830 text text/html http://www.bruzelius.info ... en ... ... Copyright © 2002 Lars Bruzelius

Windlass.—The ship being now supposed all bound, decks laid, ceiling on, and all caulked, we have next to take notice of the windlass and capstan, and give the necessary directions for making and fitting them up. Plate XI. Figs. 1, 2, 3, 4, & 5, are the different plans and sections of a windlass for a ship of about 300 or 320 tons. The strong line A A A represents the deck; Fig. 1, a transverse section of the middle of the windlass and pawl-bitt; Fig. 2, a semi-longitudinal section; B the half of the pawl-bitt; D the principal piece of the windlass; C the winlass-bitt; E the windlass end; F F and G G the casing or welps. The principal piece of the windlass, marked D in all the figures, is an octagon, whose diameter at the center and at the inside of the range-bitt C, is represented by Figs. 1 and 4; Figs. 1 represents also the pawl-ring, pawls, and pawl-plate, according to the most approved (although not the latest) construction. Fig. 4 shews the diameter of the preventer, and the bush and spindle. The ends of the piece D (Fig. 2) are bound with the iron hoop marked a. The ends of the principal of the windlass are cut in square as far as the letter b, leaving the projecting part c (Fig. 3) to go two inches into the range-bitt, which is cut quite true to the circle, and the hoop b (Fig. 4) driven tightly on it. This circular projecting part on the main piece of the windlass is intended to form a journal on which the windlass would revolve independent of the iron spindle H; and if the spindle should give way, the projecting part would still secure the windlass; and as in riding it tends to prevent those heavy jerking strains from the cable overstraining and breaking the spindles, it is called the preventer spindle. The hoop b is commonly called the preventer or collar-ring; d (Fig. 4) is a square plate, with a small hole in each corner, about one-half inch thick, made to fit very neatly on the spindle, close up to the round; it is let flush into the end of the windlass, and fastened with the corner bolts a, before the spindles are driven in. The spindle H is generally from 3 to 3½ feet long, and its diameter from 2½, 3 to 3½ inches, according to the size of the vessel,— (the rule for its exact diameter is given in our general dimensions and proportions, p. 159); it is driven very tight, half into the windlass and half into the windlass-end, as shewn on the drawing; of course the spindle is square, except at the part which turns in the bush, and is tapered towards the ends. The windlass-ends are commonly made of sufficient length to take in two handspike-holes; they are hooped with the iron hoop e, and have also a copper-plate let in and fastened with four small bolts before the ends are drove on to the spindle. And particular care is taken, in marking the place of the holes f in the spindle, to bore the same through the windlass and ends, so as to get a locking bolt drove through. F F and G G are whelps or casing pieces bolted or nailed round the windlass and end, to protect the main-pieces from being cut or destroyed by the cable.

Fig. 5 represents the common metal bush and dog-bolt, h the bush, ij the dog-bolt which supports it. The bush is made with a square groove in the under side, and also up the after part, as deep as to take in 1-3d of the bolt, which is square at that part. The fore side of the bush has a small tenon let 3-4ths of an inch into the bitt, which together with the groove over the bolt and up the after side of the bush, prevent it from moving or working the side way when the ship is rolling.

The dog-bolt g is made with a screw and nut on its after end (see the Fig.) for the purpose of holding down the after end of a flat plate of iron, the fore end of which fits into a chock on the fore part of the bush. The dog-bolt is commonly drove in slack, or burned in for a good part of the way, (which prevents it from rusting), and locked on the fore part of the knee of the bitts.

Fig. 3 shews the windlass-bitt C, with an improved bush, l the foremost piece; it is a little larger than the other, and comes about half an inch abaft the centre of the spindle at the lower side, so that it may not run exactly on the joint of the two pieces of the bush. The upper part of the fixed or fore half of the bush has a small piece taken off, as shwen in the figure, and the after part or half made to fit into it, so that the spindle may go into the bush at the full size. The after half of the bush, marked J, is made short of the fore half, and to natch into it, or bear against two studs, which prevents any upward strain from coming upon the bolts, which are therefore only exposed to a fore-and-aft strain. The two strong bolts pass through the windlass-bitt and knee, and being screwed at their after ends, nuts are put on for securing the after half of the bush. The after part of the windlass-bitts is fixed on by means of two strong bolts forelocked on the fore side of the bitts or knee, as shewn on the plate.

After the above short reference to the plate, we are now prepared to offer a few directions for completing this part of the outfit of the vessel.

The main piece of the windlass should be of the very best British oak, if it can be got, as this, at least in my opinion, is preferable to all others, African oak bot excepted.

The piece of timber intended for the windlass must be very carefully examined before it is cut, because from its particular form, after being sawn to the squares and taper, and perhaps some of the handspike-holes cut, should any defect in the piece be discovered after it is dressed, it will of course be condemned, altough its particular shape renders it very unfit for being converted into any other purpose without great waste of material. If, after a careful examination, it is found to be perfectly sound, line it first to a four-square to the proper size. Its length between the bitts is half the main breadth of the ship on deck, and the thickness in the middle 2-3ds of the ship's extreme breadth, taking inches for feet, and parts for inches. It must be kept of equal size in the middle, to the breadth of the pawl-bitt, to receive the cast-metal pawl-ring. The length of the windlass between the bitts, as stated, is one-half the breadth at midships on deck, but may be a small thing less than this, if sufficient room and number of handspike-holes can be obtained. The end diameter, i.e. at the inside of the bitts, is 5-6ths of the main diameter. After it is lined to a four-square to these dimensions, it must be sawn and next dressed to an exact eight-square.

Before doing more than prepare the ends, you must have the pawl and windlass-bitts set and squared in their proper positions on the deck. Then take the exact length between the bitts, with a straight batten, at the same time marking on the batten the place of the pawl-bitt, also the most proper and convenient place for the handspike-holes; apply the batten to the piece timber, set off its exact length, and allow for the breadth of the preventer or collar-ring, which is about two inches or so for vessels from 150 to 300 tons. The ends must be neatly squared over from the center-lines along the four sides, and after they are cut, scrive lines from the four opposite sides, crossing each other at right angles, and of course their intersection is the centre of the spindle; from this centre, and on the four lines, set off the exact square of the spindle, and with the compasses draw a circle within the square, in order to centre the auger or piercing-bitt by which the windlass is bored to receive the spindle; the same precautions must also be taken in dressing and squaring over the ends, and finding the centre for the spindle in the windlass-ends. It is the most general custom to bore only a little farther into the windlass than the length of the spindle requires, but in some parts they bore the spindle-holes right through from one end to the other, which I think is the best and most convenient method for getting the spindles fitted tiht and fair into the windlass, as they can be easily struck out in fitting them, and helped a little if required; whereas, when the windlass is not bored throughout, it is very difficult to get the spindles driven back after they have been put in. Also, by boring the windlass right through from end to end, it prevents any rot from taking place in the centre of the piece by taking out the heart, which in large pieces of timber is generally soft and the first to decay, and communicates the rot to the other parts. Boring the windlass right through has no tendency to diminish its strength, but rather to preserve it.

In several parts of the United States of America, the body of the windlass is made in two pieces, or if the piece be large enough, they cut it up through the middle, and when it is dressed and joined, let the spindles half into each piece, and bolt and hoop the two pieces firmly together. The advantages of this method are the greater certainty of seeing whether the piece is perfectly sound in the middle or heart before it is farther proceeded with, and that the spindles may be put in more centrically. These advantages are no doubt important; yet as the windlass is no stronger, and as an additional expense and weight is created in fastening the two halfs together, I think the method of boring the spindle-holes right through to be the most convenient and least expensive.

When the spindle-holes are bored, the handspike-holes are next cut out about 3 inches square, and should never be nearer each other than 15 inches. In marking them off, they must be carefully squared across from all the four principal squares of the windlass, so that the mortises may meet exactly fair through one another. The windlass ends are got on with about this time.

Having already pointed out the form and position of the hoopes and bushes, and supposing the windlass made on the ground, and the pawl-bitt placed, the windlass-bitts should be in thickness 1-3d of the diameter of the windlass, and in breadth not less than a whole diameter of the same. To ascertain the place of the mortise for their lower end, strike a direct square line across the deck, at any convenient distance abaft the pawl-bitt. Then, on this transverse line, measure from the centre-line of the ship the half length of the windlass on each side, (the chocks must of course have been previously sunk in to answer this breadth); at these spots lay the stock of a square well with the transverse line on the deck, the blade of the square lying forward at the inside mark of the bitt, draw a line fore-and-aft, which will give the range of the inside of the bitt parallel with the middle line of the ship; at the thickness of the bitts, without this, strike another fore-and-aft line parallel to the last drawn, and it will mark the outside of the bitt; and this being done for both sides of the ship, next find their position in the fore-and-aft direction, that is, their distance abaft the pawl-bitt. Thus, the line of the axis of rotation is exactly a whole diameter of the windlass abaft from the pawl-bitt; therefore, at this distance abaft from the pawl-bitt, strike a straight line across the deck parallel to the first drawn transverse line, and it will represent the vertical to the centre-line of the windlass; next, at the place of the windlass-bitts, set aft from the centre-line the whole diameter of the spindle, which mark will be the after edge of the bitts, when the windlass is to be fitted with a square bush and dog-bolt; but when for two half-bushes bolted above and below, set only 1-4th of the diameter of the spindle abaft the centre-line for the place of the after edge of the bitt.

But here it must be observed, that the rule to place the centre of the windlass, its whole diameter abaft the pawl-bitt, applies particularly to wooden pawls, and only to the cast-iron pawls and pawl-ring when these have been made to answer that distance. This I believe is generally the case; but as every manufacturer is perhaps not aware that the most suitable distance for the centre of the pawl-ring abaft the pawl-bitts is half its diameter, it will be necessary, in fitting the windlass with cast-metal pawls and pawl-rings, to find what distance aft they have been calculated for, by placing the back of the pawl-plate against the coamings of the hatches, or some other straight and steady piece of wood, laying the wheel or ring on its end, and the pawls in their proper place; then measure the distance from the centre of the ring to the back of the pawl-plate, and it will give the proper distance that the centre-line of the windlass should be struck on the deck abaft the pawl-bitt. While the ring and pawls are lying in their exact position, mark the height the pawl-plate stands above the uppermost square, which will be of advantage when you come to fix the pawl-plate on the bitt. When the mortices are cut out, the bitts driven tight down into the chock and bolted, stretch a line between the bitts at the height and spot of the centre of the windlass, and observe that this centre-line and the inside of the bitts are perpendicular to each other in a fore-and-aft and up-and-down direction. The heihts of the windlass from the deck may vary a little, according to circumstances, or the peculiar [sic] rig of the vessel. Large smacks, in the Leith and London trade, have the centre of their windlass from 20 to 22 inches above deck, according to the intended stave of the bowsprit, which in these vessels runs in over the top of the windlass. But other merchant vessels, such as vessels in the coal trade, and general traders, have the centre of their windlass from 24 to 26 inches above the deck, as at this height it is found that the crew have the greatest mechanical advantage in heaving upon the windlass.

Having marked the height of the centre of the windlass above the deck, square it across the inside and outside of the bitts, observing to make them range level across the ship; next, from the cross-line on the inside, strike another, forming an inclination to it, so that it shall radiate exactly from the intended centre of the bush; this being done on the outside of the bitts also, the intersection of these lines must be found by means of two small straight-edged battens, when letting in the bushes, in order to enable you to fit them in exactly to their proper place. The bushes must lie perfectly level across, and range well with each other in every direction, that the spindles may fit close, and run easy in the bushes. After the bushes are properly fitted, the windlass must then be lifted into its place and turned round, to see if the bushes are placed well with its centre, and if it is true of itself; to prove which, nail a batten on the side of the pawl-bitt, reaching aft over the windlass, just touching the highest square; then by turning it gently round, you observe how much the lowest square is off from the batten, and if the distance is more than what the pawl-ring is wider than the diameter of the windlass, the full side must be reduced, so that the centre of the pawl-ring may come fair with the axis of the windlass. The ring should always be 1 to 1½ inches larger in diameter than the windlass, to allow of its being wedged true, so that in turning the windlass the pawl-ring may revolve exactly on its own centre; for if this is not exactly the case, it will go up and down with an eccentric motion, and the pawls will not fit exactly in all the squares, and on this account the windlass will be very deficient, as some of the pawls will be bearing hard, while the others, that should bear equally at the same thing, will be slack and quite open. In order to make a good job of the windlass, not only the material, but also the workmanship, both in wood and iron, must be of the very best description, and every part truly wrought.

The inside diameter of the pawl-ring should be one inch at least larger than the windlass, so as to allow half an inch all round for getting it set fair to the centre of rotation, and to allow room for the wedges; but should it happen that a ring cannot be obtained larger than the exact diameter of the windlass, it is the best way, in this case, as soon as the windlass is hung upon the spindles, to turn it perfectly true in the middle upon its own axis; divide it exactly into the eight squares, and dress it to the neat size of the inside diameter of the ring, and then drive the ring tightly on. By this means it may be brought very near the truth — at the same time it is more easily set correct by means of the wedges. Accordingly, when the ring is put to its place, set it equally off the squares of the windlass, turning it gently round, at the same time having a batten fixed to the pawl-bitt to direct you in placing it true to the centre, in which position you must fix it by a number of temporary wedges or slips, placed on the four opposite squares. The ring being set true with these, they must be driven pretty tightly in; then prepare to drive in those on the other four opposite squares for a full due. The proper wedges must be made of very dry hard wood, two for each square, and driven one each end of the ring on the same square; they should be in breadth equal to the plane, and tapered off neatly, so that both points may come through to the opposite sides. They should never be made so as to bear hollow, but be solid, and equally tight throughout the whole breadth of the ring. Fit all the wedges of the four squares before beginning to drive any of them tight, which you must do by driving only a little upon the wedges of the opposite squares at a time, so that you do not alter the position of the centre of the ring during the time of driving the wedges or slips. When the first four squares are wedged sufficiently tight to keep the ring from shifting, take out the temporary ones on the four opposite squares; then fit and drive in moderately tight the proper ones. Try the windlass round, observe the revolutions of the ring, and if it present an eccentricity from the true rotation on the spindles, this may be adjusted by setting up the wedges to an equal degree of tightness, If the windlass has been made for some length of time, and exposed to the drought, the wedges must not be driven very tight, otherwise there will be some risk of the ring breaking by the expansion of the windlass when it is exposed to wet or dampness,

When the ring is properly fixed, the next thing is to fit and fix the pawl-plate on to the pawl-bitt. When it is temporarily held to the pawl-bitt, at the exact height, or as near thereto as possible, try in three of the pawls into the ratchets of the ring, the uppermost, the square or level pawl, and also the under oen; and should the square or level pawl fit hard, while the other two are slack, the plate must be let a small thing back into the pawl-bitt; at the same time, great care msut be taken that it is not let too far back, which would cause the pawls to stand off their proper centre, and point too much towards the centre of the ring, in place of bearing at a tangent to its circumference on the square of their ends. If the uppermost pawl is close, and the under one open from the ratchet, the plate must be raised a little, and vice versa.

The plate should be made to fit very solidly against the pawl-bitt, otherwise it may be broke with a small jerk or strain on the windlass. When the plate is placed and bolted on as near its true place as possible, and the pawls set in, if they are not all bearing fair at the proper parts of the revolution of the windlass, the ends of those that are long must be pared off with a cold chissel, and the whole made to fit to their exact and proper bearing. This should be attended to after the vessel is launched into the water, as there are few or no ships but what will make some little alteration in this respect, after they are fairly afloat for a little time.

After the pawls are fitted, the casing of the windlass is next put on. It is commonly oak or elm, as this stands well, and bears the chafing and cutting of the cable better than most other kinds of timber; but as it nevertheless wears fast, such vessels are exposed to much anchorage have commonly the working side of the windlass covered with strong sheet iron, or pieces of cast iron of the same form as the casing, on four of the opposite squares. In large smacks, there are two pawl-bitts, and the windlass is accordingly fitted with two pawl-rings and pawls, the bowsprit coming in between them. In this case, the rings and pawls are rather narrower and lighter than when there is only one employed; also the windlass for large vessels should have three sets of pawls, one in the middle, and one at each end attached to the range-bitts.

Improvements on the Windlass.— The most important improvement on the windlass is the cast-metal pawls and pawl-rings. Before its invention, the pawls were made of good oak timber, well seasoned, and the ratchets were cut out of the body of the windlass into eight principal wood locks or ratchets. In the year 1786, Captain Stephen Wright obtained a patent for applying iron axles or spindles and iron pawls (stopping at every 16th square) in the middle and at the windlass-bitts. About the same time, Mr. Moore of London obtained a patent for his balance-pawls.

Sowerby's Patent Pawl consists in forming the pawls all of one piece, as represented by Figs. 12 and 13, Plate XI.; also a cast-metal riding chock. A is the toothed rim, or cylindrical ring, B the pawl or back-plate, C the working-pawl, D the riding-chock, E the riding-chock shoe, bolted to the pawl-bitt and to the deck through the piece of timber F. Fig. 12 is a side view of the apparatus, as when getting the anchor; Fig. 13 shews the position of the pawl and riding-chock, supposing the vessel at anchor. There is also a lever or crow-bar for raising the riding-chock into gear with the rim, through the opening O, when wedging it up; also for starting the wedge W before heaving. When the windlass is hove round (Fig. 12), the working-pawl rises and falls perpendicularly in the succession of the teeth on the pawl-ring, thus pawling at once every tooth on a considerable portion of its circumference.

Before rinding [sic] or veering the cable, the riding-chock is raised by a crow-bar, the wedge W being at the same time driven in, until the chock is firmly geared with the ratchets or sheath of the rim, as shewn by Fig. 13.

The advantages which the patentees supposes this invention to possess over the common pawls are — 1st, The working-pawl offers a more solid resistance than a series of pawls such as are commonly used, whilst its action against the pawl-bitt is nearer the deck. 2d, It cannot be upset, as, from its wedge-like form, it becomes the more firmly fixed as the strain increases; consequently the anchor may be got by it, when with the common pawls it would be most hazardous to attempt it. 3d, It is not deranged by the screwing, or otherwise straining the deck-timbers, but falls alike, however the body of the windlass is raised or depressed. 4th, If the cable ride, or a handspike get fast, and if it be required to run the windlass backwards (Fig. 13), it may be done instantly by raising the pawl, which may be as quickly replaced, 5th, For riding or veering, the windlass becomes a complete fixture with the pawl-bitt and decks, and cannot be moved by any jerk or strain whilst they remain fast. It is not only supposed much more effective in supporting and securing the windlass than the wooden chocks now in use, but also in preventing the least reaction or working of the windlass, as it is secured alike in every direction.

The original cost of the whole apparatus is said to be much less than that of the common pawls and riding chocks; it requires less time and art in fitting, and it is not liable to get out of repair.

The following are the inventor's directions for fitting it:—

The Windlass Body, Bitts, and Necks, are fitted in the ususal way.

The Pawl-bitt. — Its after side must be perpendicular, and distant from the centre-line, equal to about three-fourths of the inside diameter of the rim.

The Rim, or Cylinder, must be firmly and accurately wedged upon the windlass body.

The Pawl and Back-plate. — Place the pawl on the top of the rim, and turn the windlass backward, until the back of the pawl is parallel to the bitt, or to a plumb-line; and if the pawl-bitt be at a greater distance than the thickness of the back-plate (as in vessels which have formerly had the common iron pawls), it must be adusted by facing a piece of timber on the after-side. This done, bolt the back-plate to the bitt, the ends of its side-flanges being opposite the centre-line, so that when the pawl is in its place, and a strain upon it, its distance from the under side of the bracket may be equal to about one-eighth of the inside diameter of the rim. Its low end must fit close against the back-plate, and its top tooth must be a little short of its bearance against the teeth on the rim. The working-pawl being thus properly fitted, raise.

The Riding Chock with the wedge W, until the point of the wedge is at the middle of the opening O. Then raise the whole against the after-side of the pawl-bitt, until the teeth of the riding chock gear close with the teeth of the rim; taking care that the shoe be so far aft that the back of the riding-chock, when in gear, be close against the shoe, which will generally require a thin piece of wood between the shoe and the face of the pawl-bitt; and also that the wedge be not slack at the thin end. The timber F must then be fitted between the shoe and the deck, and the shoe bolted to the pawl-bitt, and through the timber to the deck.

If the work be correct, the chock will gear easily, the wedge requiring but a blow or two with the handspike, when the windlass will be so firmly held as not to be moved either way. The wedge may be instantly and easily started by a stroke of the lever, which should be made fast to the pawl-bitt, as most convenient.

N.B. The inside of the pawl-plate and back of the pawl should occasionally be rubbed with black lead.

The ingenuity of this invention is considerable; yet it appears evident that it is not altogether complete. From the wedge-like form of the pawl, and the want of a stopper on the pawl-plate, it will throw a very severe and unnecessary strain on the windlass and pawl-bitt, by tending to wedge the former aft from the bitt. This of course could easily be prevented by having a projecting pin on the plate.

Yett's Patent Apparatus, for securing the windlass when at anchor, is so generally known, that any description of it here is unnecessary.

The first idea of increasing the power of the windlass beyond that of the common handspikes, or windlass-bars, was suggested and tried by Mr. William Hutchinson of Liverpool, and is described in his Treatise on Practical Seamanship, about the time of Wright's improvement. Mr. H. proposed, when very great strains were to be hove with the windlass, to have one or two long bars extending across the windlass, with two ragged wheels; and when the square and all the pawls are properly down, the middle of the bar to be laid on the windlass close by the bitts, right above the top-tooth of the ragged wheel, with the fore-end down to the deck, so that the after-end of the bar will be so high that a man may reach it from the deck; and havig one or two men at each end of this bar, those before the windlass will be lifting it up with all their power, while those abaft the windlass will be pulling down with all their might. The windlass may thus be hove round, when perhaps it could not be started one pawl by the people swinging on the common handspikes.

The power of the windlass is estimated thus, (and the principle is the same as the wheel and axle, formerly explained in our treatise on Mechanics):— As the semi-diameter of that part where the cable is woundround, is to the semi-diameter of the circle described by that part of the handspikes where the medium weight of the men is excerted; so is the weight of the of crew to the power of the windlass, or weight of the anchor or body which is to be raised by it.

As a means of aiding or increasing the power of the windlass, a large wheel is now fixed on the spindle at one end, and a large crank handle, on the shaft of which is fixed a pinion working into the teeth of the wheel, which is hove round in the same manner as the winch. This is chiefly used in getting the anchor inlarge vessels.

Another patent has been lately obtained for effecting the same purpose by Keenlyside and Company, Newcastle. This improvement is represented by Figs. 14 and 15, Plate XI. B is the pawl-bitt, C the windlass-bit, D the body of the windlass, E a small windlass above the main one, F a chain passing round the main windlass, and oveer a ratchet-wheel E (Fig. 15); so that when the upper spindle is hove round, the windlass is turned in the same direction with an increased power of 4 to 1.

Peter Hedderwick: A Treatise on Marine Architecture, containing the theory and practice of shipbuilding, with rules for the proportions of masts, rigging, weight of anchors, &c including Practical Geometry and the Principles of Mechanics; observations on the Strength of Materials, Hydrostatics, &c. with many valuable tables calculated for the use of shipwrights and seamen; also the proportions, scantlings, construction, and propelling power of steam-ships. Illustrated with twenty large plates, containing plans and draughts of merchant-vessels from fifty to five hundred tons, with mast and rigging plans; plans and sections of a steam-boat of eighty-horse power; and eight quarto plates of diagrams, &c., by Peter Hedderwick.
Printed for the Author, Edinburgh, 1830. pp 302-310.

Transcribed by Lars Bruzelius.

Sjöhistoriska Samfundet | The Maritime History Virtual Archives | Shipbuilding | Search.

Copyright © 2002 Lars Bruzelius.