SHIP-BUILDING.
SHIP-BUILDING may be defined, The manner of constructing ships, or the work itself; as distinguished from NAVAL ARCHITECTURE, which may be considered as the theory or art of delineating ships on
a plane. The latter was referred to this place, that we might avoid the impropriety of giving the theory and practice under different articles.
PART I. ART OF DELINEATING SHIPS ON A PLANE.
ALL edifices, whether civil or military, are known to be erected in consequence of certain established plans, which have been previously altered or improved till they have arrived at the desired point of perfection. The construction of ships appears also to require at least as much correctness and precision as the buildings which are founded upon terra firma: it is therefore absolutely necessary that the mechanical skill of the shipwright should be assisted by plans and sections, which have been drawn with all possible exactness, examined by proper calculations, and submitted to the most accurate scrutiny.
Naval architecture may be distinguished into three principal parts.
First, To give the ship such an exterior form as may be most suitable to the service for which she is designed.
Secondly, To give the various pieces of a ship their proper figures; to assemble and unite them into a firm compact frame, so that by their combination and disposition they may form a solid fabric, sufficient to answer all the purposes for which it is intended. And,
Thirdly, To provide convenient accommodations for the officers and crew, as well as suitable apartments for the cargo, furniture, provisions, artillery, and ammunition.
The exterior figure of a ship may be divided into the bottom and upper works.
The bottom, or quick-work, contains what is termed the hold, and which is under water when the ship is laden. The upper works, called also the dead-work, comprehend all that part which is usually above the water when the ship is laden.
The figure of the bottom is therefore determined by the qualities which are necessary for the vessel, and conformable to the service for which she is proposed.
The limits of our design will not admit of a minute description and enumeration of all the pieces of timber which enter into the construction of a ship, nor of a particular description of their assemblage and union, or the manner in which they reciprocally contribute to the solidity of those floating citadels. It nevertheless appears necessary to give a general idea of the use, figure, and station of the principal pieces, to those who are entirely unacquainted with the subject. As our definitions will be greatly illustrated by the proper figures, we have annexed to this article a plate, which comprehends some of the most material draughts, as
well as a representation of the principal pieces employed in naval architecture.
It is usual among shipwrights to delineate three several draughts.
First, The whole length of the ship is represented according to a side-view, perpendicular to the keel, and is termed the plane of elevation, or sheer-draught. Plate CCXLVI. fig. 1.
Second, The ship is exhibited according to an end-view, and stripped of her planks, so as to present the outlines of the principal timbers; and this is properly termed the plane of projections, or the vertical plane of the timbers, (fig. 4.) because it shows the projection of their frames relatively to each other.
Third, It is not sufficient to have the vertical curves of the bottom in different places, for a distinct idea of the horizontal curves is also equally necessary and useful: this is obtained by means of water-lines, traced upon what is called the horizontal plane, (fig. 2.) In this draught the curves of the transoms called the round-ast is also marked, and sometimes the breadth and thickness of the timbers.
The plane of elevation (fig. 1.) determines the length and depth of the keel; the difference of the draughts of water; the length and projection, or rake, of the stem and stern-post; the position of the midship-frame upon the keel, together with that of the principal frames afore and abaft; the load-water line; the wales; the dimensions and situations of the gunports; the projection of the rails of the head and stern-gallery; with the stations of the masts and channels.
This draught, however, conveys no idea of the vertical curve of the ribs or timbers; for as their projection will be only represented in a plane elevated upon the length of the keel, they will appear in this direction no otherwise than as straight lines. To perceive these curves accurately, they must be regarded in another point of view; which will represent their projection upon a vertical plane, supposed to cut the keel at right angles in the place where the ship is broadest. For as all ships are broader near the middle of their length than towards the extremities, it is evident that the timbers are more extended in proportion. The most capacious of these represents what is called the midship-frame; and upon the area of this frame is delineated the projection of all the others.
Thus the plane of projection limits the different breadths of a ship in various points of her length, and exhibits the outline of the timbers respectively to each other.
other as they are erected upon the keel. Accordingly, this draught ought to present a variety of sections of the ship in different places of her length, and always perpendicular to the surface of the water; so that the eye of the observer, when placed in what may be properly termed the axis of the ship, may perceive the several sections at one glance; that is to say, when looking full on the stem from before the ship †, he shall discover the fore-timbers; and when looking from behind, directly on the stern, he shall perceive the form of the after-timbers. See Plate of STERN, fig. 2. 3. at the article STERN; in both of which figures the sections of the inferior timbers are expressed by curved black lines drawn upon the area of the midship-frame, which is already described to be a plane elevated perpendicularly upon the keel at the extreme breadth of the vessel. See Midship-Frames.
To form a just idea of this plane, therefore, we ought to suppose a ship resting upon the stocks, in the same position as when afloat upon the water. Thus a variety of black vertical lines may be drawn at equal distances upon the bottom, which is white, to form different outlines of the ship corresponding to the timbers within. It is to be observed, that the fashion of the inferior timbers must conform to the figure of the midship-frame, which is placed in the fullest part of the ship; and as the planes of all the other timbers diminish in a certain progression as they approach the stem and stern, they are properly delineated on the plane of the midship-frame, which also represents the depth of the keel and length of the midship-beam.
As the two sides of a ship ought to be exactly alike, it is judged sufficient to represent the sections of the fore-part of the ship on the left side, and those in the after-part on the right side, so as to perceive all the sections, as well afore as abaft, upon one plane. See Plate CCLXVI. fig. 4.
However necessary it may be to understand precisely the vertical curves of the bottom, it is no less requisite to have a just idea of those which are horizontal.
The horizontal, or floor-plane, is that upon which the whole frame is erected, and will be more clearly understood by previously describing the water-lines and ribbands of which it is composed.
When a ship floats upon the stream, it is evident that her upper works will be separated from the bottom by the surface of the water, which will accordingly describe an imaginary horizontal line upon the bottom from the stem to the stern-post.
The most elevated of those lines is termed the load water-line, which is supposed to be drawn by the surface of the water on the upper part of the bottom, when she is sufficiently laden for a sea-voyage. For if we suppose this surface a rule, and thereby describe a corresponding black line along the vessel's bottom, that line will be distinguished upon the bottom, which is white, and represent what is called the load water-line.
If the ship is lightened of any part of her lading, and preserves the same difference in her draught of water at the two ends; or, what is the same thing, if she is lightened so as to preserve the same equilibrium of the keel with regard to the surface of the water, it is evident that she will rise higher out of the water, so that the black line already described will be elevated
above it; and another black line may be delineated upon the bottom, close to the surface of the water, which will exhibit a second water-line parallel to the first, but nearer the keel in proportion to the number of feet which the ship has risen.
Thus by lightening a ship gradually, and at the same time preserving the direction of her keel, or the angle which the keel makes with the surface of the water, a variety of water-lines may be drawn parallel to each other and to the load water-line. See a farther illustration of these lines in the article WATER-LINE.
The ribbands are likewise of great utility in ship-building; they are narrow and flexible planks placed on the bottom at different heights, so as to form a sort of mould for stationing the inferior timbers between the principal ones. They differ from the water-lines, inasmuch as the latter have only one curve, which is horizontal; whereas the ribbands, besides their horizontal one, have a vertical curve. To convey a just idea of these curves, which cannot be represented on one draught at their full length, without an oblique section of the ship's length, it will be necessary to have recourse to two planes; that of the elevation, which exhibits their vertical curve; and to the floor-plane, upon which the horizontal curve is expressed. See RIBAND, and TIMBER.
These different lines are extremely useful in exhibiting the various curves of a ship's bottom, that as they are gradually diminished, their uniformity or irregularity may be discovered by the skilful artist.
The qualities required in a ship ought to determine the figure of the bottom. A ship of war, therefore, should be able to sail swiftly, and carry her lower tier of guns sufficiently out of the water; otherwise a small ship will have the advantage of a large one, inasmuch as the latter cannot open her lower battery in a fresh side-wind without being exposed to extreme danger by receiving a great quantity of water in at her ports between decks. A merchant-ship ought to contain a large cargo of merchant-goods, and be navigated with few hands: And both should be able to carry sail firmly; steer well; drive little to leeward; and sustain the shocks of the sea without being violently strained.
The first thing to be established in the draught of a ship is her length; and as a ship of war, according to her rate, is furnished with a certain number of cannon, which are placed in battery on her decks, it is necessary that a sufficient distance should be left between their ports to work the guns with facility; and particularly to leave space enough between the foremost gun and the stem, and between the aftmost gun and the stern-post on each side, on account of the arching or inward curve of the ship toward her extremities.
When the length of a ship is determined, it is usual to fix her breadth by the dimensions of the midship-beam. On this occasion the shipwrights, for the most part, are conducted by rules founded on their own observation; for having remarked, that some vessels, which by repeated experience have been found to answer all the purposes of navigation, have a certain breadth in proportion to their length, they have inferred that it would be improper to depart from this proportion: but as other ships have been constructed with
† See
Pl. CLIX.
fig. 2.
Fig. 1.
ELEVATION.
Fig. 3.
PIECES of the HULL.
Fig. 4.
PROJECTION.
with different breadths, which were equally perfect, a variety of different general rules have been adopted by these artists; who are accordingly divided in their opinions about the breadth which ought to be assigned to a ship relatively with her length, whilst each one produces reasons and experience in support of his own standard. Those who would diminish the breadth, allege, 1. That a narrow vessel meets with less resistance in passing through the water: 2dly, That by increasing the length she will drive less to leeward: 3dly, That, according to this principle, the water-lines will be more conveniently formed to divide the fluid: 4thly, That a long and narrow ship will require less sail to advance swiftly; that her masts will be lower, and her rigging lighter; and, by consequence, the seamen less fatigued with managing the sails, &c. Those, on the contrary, who would enlarge the breadth, pretend, 1st, That this form is better fitted to preserve a good battery of guns: 2dly, That there will be more room to work the guns conveniently: 3dly, That, by carrying more sail, the ship will be enabled to run faster; or, that this quality will at least overbalance the advantage which the others have of more easily dividing the fluid: 4thly, That being broader at the load-water line, or place where the surface of the water describes a line round the bottom, they will admit of being very narrow on the floor, particularly towards the extremities: And, 5thly, That a broad vessel will more readily rise upon the waves than a narrow one. From such opposite principles has resulted that variety of standards adopted by different shipwrights.
It has been remarked above, that a ship of war must carry her lower tier of cannon high enough above the water, otherwise a great ship which cannot open her lower battery, when sailing with a fresh side-wind, may be taken by a small one that can make use of her cannon.
A ship should be duly poised, so as not to dive or pitch heavily, but go smooth and easy through the water, rising to the waves when they run high and the ship has reduced her sail to the storm; otherwise they will break aboard, and strain the decks or carry away the boats; the masts are likewise in great danger from the same cause.
A ship should sail well when large and before the wind, but chiefly close-hauled, or with a side-wind, and her sails sharp-trimmed, and then not fall off to the leeward.
Now, the great difficulty lies in uniting so many different qualities in one ship; which seems to be nearly impossible: the whole art, therefore, consists in forming the body in such a manner that none of these qualities should be entirely destroyed, and in giving a preference to that which is chiefly required in the particular service for which the vessel is designed. We shall briefly show the possibility of uniting them all in one ship, that each of them may be easily discerned: when it happens otherwise, the fault must lie in the builder, who has not applied himself to study the fundamental rules and principles of his art.
To make a ship carry a good sail. A flat floor-timber, and somewhat long, or the lower futtock pretty round, a straight upper futtock, the top-timber to throw the breadth out aloft; at any rate, to carry her main breadth as high as the lower deck. Now, if
the rigging be well adapted to such a body, and the upper works lightened as much as possible, so that they all concur to lower the centre of gravity, there will be no room to doubt of her carrying a good sail.
To make a ship steer well, and answer the helm quickly. If the fashion-pieces be well formed, the tuck, or spreading parts under the stern, carried pretty high, the midship-frame well forward, a considerable difference in the draught of water abaft more than before, a great rake forward and none abaft, a snug quarter-deck and fore-castle; all these will make a ship steer well. A ship which sails well will certainly steer well.
To make a ship carry her guns well out of the water. A long floor-timber, and not of great rising; a very full midship-frame, and low tuck, with light upper works.
To make a ship go smoothly through the water without pitching hard. A long keel, a long floor, not to rise too high afore and abaft; but the area or space continued in the fore-body, according to the respective weights they are to carry; all these are necessary to make a ship go smoothly through the water.
To make a ship keep a good wind, and drive little to the leeward. A good length by the keel; not too broad, but pretty deep in the hold, which will occasion her to have a short floor-timber and a great rising. As such a ship will meet with great resistance in the water going over the broadside, and little when going ahead, she will not fall much to the leeward.
Now, some builders imagine it is impossible to make a ship carry her guns well, bear a good sail, and be a prime sailer; because it would require a very full bottom to gain the first two qualities, whereas a sharp ship will answer better for the latter: but when it is considered that a full ship will carry a great deal more sail than a sharp one, a good artist may so form the body, as to have all these three good qualities, and also steer well.
We shall now proceed to describe the principal pieces of which a ship is composed, and to explain the principal draughts used in the construction thereof.
As the several lines exhibited in the planes of elevation, projection, &c. will be rendered more intelligible by a previous account of those pieces, it may not be improper to begin with reciting their names, and giving a summary description of their uses and stations. They are for the most part represented according to the order of their disposition in that part of Plate CCLXVI. which is termed pieces of the hull.
A. The pieces which compose the keel, to be securely bolted together, and clinched.
B. The stern-post, which is tenanted into the keel, and connected to it by a knee, G. It supports the rudder, and unites the sides of the ship abaft.
C. The stem, which is composed of two pieces scarfed together: it is an arching piece of timber, into which the ship's sides are united forwards.
D. The beams, which are used to support the decks, and confine the sides to their proper distance.
E. The false post, which serves to augment the breadth of the stern-post, being also tenanted into the keel.
F. The knees which connect the beams to the sides.
G. The kate of the stern-post, which unites it to the keel.
H. The apron, in two pieces: it is fayed on the inside of the stem, to support the scarf thereof; for which reason the scarf of the former must be at some distance from that of the latter.
I. The stemson, in two pieces, to reinforce the scarf of the apron.
K. The wing-transom: it is fayed across the stem-post, and bolted to the head of it, having its two ends let into the fashion-pieces.
L. The deck-transom, parallel to the wing-transom, and secured in the same manner.
M N. The lower transoms.
O. The fashion-piece on one side; the heel of it is connected with the dead-wood, and the head is secured to the wing-transom.
P. The top-timbers, or upper parts of the fashion-pieces.
Q. The knees, which fashion the transoms to the ship's side.
R. The breast-hooks, in the hold; they are fayed across the stem, to strengthen the fore-part of the ship.
S. The breast-hooks of the deck: they are placed immediately above the former, and used for the same purposes.
T. The rudder, which is joined to the stern-post by hinges, and serves to direct the ship's course.
U. The floor-timbers; they are laid across the keel, to which they are firmly bolted.
V. The lower futtocks, and,
W. The top-timbers, which are all united to the floor-timbers, forming a frame that reaches from the keel to the top of the side.
X. The pieces which compose the kelson: they are scarfed together like the keel pieces, and placed over the middle of the floor-timbers, upon each of which they are scored about an inch and a half, as exhibited by the notches.
Y. The several pieces of the knee of the head; the lower part of which is fayed to the stem; the heel being scarfed to the fore-foot.
Z. The cheeks of the head or knees, which connect the head to the bows on each side.
&c. The standard of the head, which fastens it to the stem.
a. The cat-heads, one of which lies on each bow, projecting outwards like the arm of a crane. They are used to draw the anchors up to the top of the side without injuring the bow.
b. The bits, to which the cable is fastened when the ship rides at anchor.
c. The false post, in two pieces, fayed to the fore-part of the stern-post.
d. The side-counter-timbers, which terminate the ship abaft within the quarter-gallery.
e. Two pieces of dead-wood, one afore and another abaft, fayed on the keel.
In vessels of war, the general dimensions are established by authority of officers appointed by the government to superintend the building of ships. In the merchant-service, the extreme breadth, length of the keel, depth in the hold, height between decks and in the waste, are agreed on by contract;
and from these dimensions the shipwright is to form Plate a draught suitable to the trade for which the ship is CCLXVI. fig. 3. designed.
In projecting the draught of a vessel of war, the first article to be considered is her length. As all ships are much longer above than below, it is also necessary to distinguish the precise part of her height from which her length is taken: this is usually the lower gun-deck, or the load water-line. It has been already observed, that water-lines are described longitudinally on a ship's bottom by the surface of the water in which she floats, and that the line which determines her depth under the water is usually termed the load water-line. In this draught it will be particularly necessary to leave sufficient distance between the ports.
The next object is to establish the breadth by the midship-beam. Although there is great difference of opinion about proportioning the breadth to the length, yet it is most usual to conform to the dimensions of ships of the same rate. After the dimensions of the breadth and length are determined, the depth of the hold must be fixed, which is generally half the breadth; but the form of the body should be considered on this occasion; for a flat floor will require less depth in the hold than a sharp one. The distance between the decks must also be settled.
We may then proceed to fix the length of the keel, by which we shall be enabled to judge of the rake of the stem and stern-post. The rake is known to be the projection of the ship at the height of the stem and stern-post beyond the ends of the keel afore and abaft, or the angle by which the length is increased as the fabric rises. To these we may also add the height of the stem and wing-transom.
After these dimensions are settled, the timbers may be considered which form the sides of the ship. A frame of timbers, which appears to be one continued piece, is composed of one floor-timber, U, whose arms branch outward to both sides of the ship; two or three futtocks, V V; and a top-timber, W. The futtocks are connected to the upper arms of the floor-timbers on each side of the ship, and serve to prolong the timber in a vertical direction: and the top-timbers are placed at the upper part of the futtocks for the same purpose. All these being united, and secured by cross-bars, form a circular inclosure, which is called a frame of timbers. And as a ship is much broader at the middle than at the extremities, the arms of the floor-timber will form a very obtuse angle at the extreme breadth: but this angle decreases in proportion to the distance of the timbers from the midship-frame, so that the foremost and astmost ones will form a very acute angle. Floor-timbers of the latter sort are usually called crutches.
Shipwrights differ extremely in determining the station of the midship-frame; some placing it at the middle of the ship's length, and others further forward. They who place it before the middle allege, that if a ship is full forwards, she will meet with no resistance after she has opened a column of water; and that the water so displaced will easily unite abaft, and by that means force the ship forward; besides having more power on the rudder, in proportion to its distance from the centre of gravity: this also comes nearer the form
Plate CCLXVI. form of fishes, which should seem the most advantageous for dividing the fluid.
When the rising of the midship-floor-timber is decided, we may then proceed to describe the rising-line of the floor, on the stern-post abaft, and on the stem afore.
The height of the lower-deck is the next thing to be considered: it is determined in the middle by the depth of the hold; and some builders make it no higher than the stem; but they raise it abaft as much above its height in the middle as the load water-mark, or draught of water abaft, exceeds that afore. With regard to the height between decks, it is altogether arbitrary, and must be determined by the rate of the ship and the service she is designed for.
It is also necessary to remember the sheer of the wales, and to give them a proper hanging; because the beauty and stateliness of a ship greatly depend upon their figure and curve, which, if properly drawn, will make her appear airy and graceful on the water.
We come now to consider the upper works, and all that is above water, called the dead-work; and here the ship must be narrower, so that all the weight lying above the load water-line will thereby be brought nearer the middle of the breadth, and of course the ship will be less strained by the working of her guns, &c. But although some advantages are acquired by diminishing the breadth, above water, we must be careful not to narrow her too much; as there must be sufficient room left on the upper deck for the guns to recoil. The security of the masts should likewise be remembered, which requires sufficient breadth to spread the shrouds. A deficiency of this sort may indeed be in some measure supplied by enlarging the breadth of the channels.
We come to explain the sheer-draught, or plane of ELEVATION of a sixty-gun ship; wherein we have been attentive to make the same letters refer to the same objects, as in the explanation of the PICES, as above; at least when the same objects are in both figures.
Fig. 1. A A. Is the keel, whose upper edge is prolonged by the dotted line pq, upon the extremities of which are erected perpendiculars which determine the height of the wing-transom K, and the length of the gun-deck KC.
A B. The stern-post.
A C. The stem.
D D. The quarter-gallery, with its windows.
E F. The quarter-pieces, which limit the stern on each side.
F. The taffarel, or upper piece of the stern.
F G. Profile of the stern, with its galleries.
H. The gun-ports.
I. The channels, with their dead-eyes and chain-plates.
K. The wing-transom.
K G. The counter.
L B. The deck-transom.
M N O. The first, second, and third transoms, of which O is the third or lowest.
M O L P. The direction of the fashion-piece, having its breadth canted aft towards the stern.
Q R. The main skeeds, for hoisting in the boats clear of the ship's side.
L Q Z. The main-wale, with its sheer afore and abaft. Plate
D R X. The channel-wales, parallel to the main-wale. CCLXVI.
S U S. The sheer-rail, parallel to the wales.
T. The rudder.
A t F. The rake of the stern.
V W V. The waist-rail.
P i. The drift-rails abaft; and i a, the drift-rails forward.
T U C. The water-line.
X X. The rails of the head.
Y. The knee of the head, or cutwater.
Z Z. The cheeks of the head.
a a. The cat-head.
M ⊕ C. The rising line of the floor.
t a C. The cutting-down line, which limits the thickness of all the floor-timbers, and likewise the height of the dead-wood afore and abaft.
⊕ a U W. The midship-frame.
a, b, c, d, e, f, g, h. The frames or timbers in the fore-body of the ship, i.e. before the midship frame.
i, 2, 3, 4, 5, 6, 7, 8, 9. The timbers in the after-body, or which are erected abaft the midship-frame.
As the eye of a spectator is supposed in this projection to view the ship's side in a line perpendicular to the plane of elevation, it is evident that the convexity will vanish, like that of a cylinder or globe, when viewed at a considerable distance; and that the frames will consequently be represented by straight lines, except the fashion-piece abaft and the knuckle-timber forward.
It has been already observed, that the plane of projection may be defined a vertical delineation of the curves of the timbers upon the plane of the midship-frame, which is perpendicular to that of the elevation. It is necessary to observe here, that the various methods by which these curves are described, are equally mechanical and arbitrary. In the latter sense, they are calculated to make a ship fuller or narrower, according to the service for which she is designed; and in the former they are drawn according to those rules which the artist has been implicitly taught to follow, or which his fancy or judgment has esteemed the most accurate and convenient. They are generally composed of several arches of a circle, reconciled together by moulds framed for that purpose. The radii of those arches, therefore, are of different lengths, according to the breadth of the ship in the place where such arches are swept; and they are expressed on the plane of projection either by horizontal or perpendicular lines: the radii of the breadth-sweeps being always in the former, and the radii of the floor-sweeps in the latter direction. These two arches are joined by a third, which coincides with both, without intersecting either. The curve of the top-timber is either formed by a mould which corresponds to the arch of the breadth-sweep, or by another sweep whose centre and radius are without the plane of projection. The breadth of the ship, at every top-timber, is limited by an horizontal line drawn on the floor-plane, called the half-breadth of the top-timbers. The extreme breadth is also determined by another horizontal line on the floor-plane; and the lines of half-breadth are thus mutually transferable, from the projection and floor-planes, to each other.
The necessary data by which the curves of the timbers are delineated, then, are the perpendicular height from the keel; the main, or principal breadth; and the top-timber breadth: for as a ship is much broader near the middle of her length than towards the end, so she is broader in the middle of her height than above and below; and this latter difference of breadth is continued throughout every point of her length. The main breadth of each frame of timbers is therefore the ship's breadth nearly in the middle of her height in that part: and the top-timber breadth is the line of her breadth near the upper ends of each timber. It has been already observed, that as both sides of a ship are alike, the artificers only draw one side, from which both sides of the ship are built: therefore the timbers abaft the midship-frame are exhibited on one side of the plane of projection, and the timbers before it on the other.
BC, The line which expresses the upper edge of the keel, from which the height of each timber and height of its different breadths are measured.
BD, and CE, Perpendiculars raised on the line BC, to limit the ship's extreme breadth and height amidships; or, in other words, to limit the breadth and height of the midship-frame.
AF, A perpendicular erected from the middle of the keel to bisect the line of the ship's breadth in two equal parts.
F 9, The half-breadth line of the aftmost top-timber; being the uppermost horizontal line in this figure.
Note, The seven lines parallel to and immediately under this, on the right-side of the line AF, are all top-timber half-breadths, abaft the midship-frame; the lowest of which coincides with the horizontal line DE.
The parallel horizontal lines nearly opposite to these, on the left side of the line AF, represent the top-timber half-breadths in the fore-body, or the half-breadths of the top-timbers before the midship-frame.
G, H, I, Q, R, S, T, The radii of the breadth-sweeps abaft the midship-frame; those of the breadth-sweeps in the fore-body, or before the midship-frame are directly opposite on the right side.
⊕ A, The midship-frame, from the extreme breadth downwards.
1, 2, 3, 4, 5, 6, 7, 8, 9, The outlines of the timbers abaft the midship-frame, in different parts of their height.
a, b, c, d, e, f, g, h, The outlines of the timbers before the midship-frame, in different parts of their height, h being the foremost or knuckle timber.
K i, the wing-transom, whose ends rest upon the fashion-piece.
L, The deck-transom, parallel to and under the wing-transom.
M N O, The lower-transoms, of which O k is the third and lowest.
m k P, The dotted line, which expresses the figure of the fashion-piece, without being canted aft.
P, The upper-part, or top-timber of the fashion-piece.
n, o, p, q, r, s, The radii of the floor-sweeps, abaft
the midship-frame: those before the midship-frame are on the opposite side of the line AF, to which they are all parallel.
1st Rd, 2d Rd, 3d Rd, 4th Rd, The diagonal ribs abaft the midships t, u, x, y. The same ribs expressed in the fore-body.
It has been remarked above, that the horizontal plane is composed of water-lines and ribands; it also contains the main and top-timber-breadth lines, or the longitudinal lines by which the main-breadth and top-timber-breadth are limited in every point of the ship's length. The horizontal curve of the transoms and harpins are also represented therein; together with the planes of the principal timbers, the cant of the fashion-piece, the length of the rake afore and abaft, the projection of the cat-heads, and the curve of the upper rail of the head, to which the curves of the lower ones are usually parallel.
BAC, The line of the ship's length, passing thro' the middle of the stem and stern-post.
B, The upper-end of the stern-post.
C, The upper-end of the stem.
BF, The length of the rake abaft.
DWX, The top-timber-breadth line, or the line which limits the breadth of each top-timber.
DF, The breadth of the aftmost timber at the taffarel.
BK, The wing-transom.
BLP, The horizontal curve of the deck-transom.
MM, The horizontal curve, or round aft, of the first transom.
MN, The horizontal curve of the second transom: it is prolonged into a water-line, N 8 7.
LO, The horizontal curve of the third transom, which is also prolonged into another water-line, O, n, U, p, Q.
m OP, The plane of the fashion-piece, as canted aft.
⊕ WU, The plane of the midship-frame.
a, b, c, d, e, f, g, h, The planes of the timbers before the midship-frame.
1, 2, 3, 4, 5, 6, 7, 8, 9, The planes of the timbers abaft the midship-frame.
XX, The figure of the upper-rail of the head.
CY, The projection of the knee of the head.
The third horizontal riband is marked on the plate.
a a, The projection of the cat-head.
Thus we have endeavoured briefly to explain the nature and uses of the principal draughts used in the construction of a ship, which reciprocally correspond with each other in the dimensions of length, breadth, and depth. Thus the plane of elevation is exactly of the same length with the horizontal or floor-plane. The several breadths of the timbers in the floor-plane, and that of the projection, are mutually transferable; and the real height of the timbers in the projection exactly conforms to their height in the elevation. Thus let it be required to transfer the height of the wing-transom from the elevation to the projection:
Extend the compasses from the point K, in the elevation, down to the dotted line prolonged from the upper-edge of the keel, and setting the other foot in the point p, then shall the line K p be the perpendicular
Plate CCLXVI. cular height in the wing-transom: transfer this from the middle of the line BAC, in the projection, to the point K in the perpendicular AF, then will AK be the height of the wing-transom in the plane of projection: and thus the height of all the transoms may be laid from the former upon the latter.
Again: Let it be required to transfer the main-breadth of the midship-frame from the projection to the horizontal plane: Set one foot of the compasses in the point on the perpendicular CE, and extend the other along the main-breadth-sweep G, till it touches the perpendicular AF parallel to CE: lay this distance upon the horizontal plane from the point in the line of the ship's length, BAC, along the plane of the midship-frame to the point ; so shall the line WU be the breadth of the midship-frame on the horizontal plane.
Thus also the top-timber-breadth, or the distance of each top-timber from the middle of the ship's breadth, may be in the same manner transferred, by extending the compasses from the line BAC, in
the horizontal plane, to the top-timber-breadth line, Plate CCLXVI. upon any particular timber, as 1, 2, 3, &c. which will give its proper dimensions thereon.
In the same manner the breadths of all the timbers may be laid from the projection to the horizontal plane, and, vice versa, from that to the projection. Thus the height of each timber may also be transferred from the elevation to the projection, &c.
The principal utility of these draughts, therefore, is to exhibit the various curves of the ship's body, and of the pieces of which it is framed, in different points of view, which are either transverse or longitudinal, and will accordingly present them in very different directions. Thus the horizontal curves of the transoms and water-lines are represented on the floor-plane, all of which are nearly straight lines in the elevation and projection; and thus the vertical curves of the timbers are all exhibited on the projection, although they appear as straight lines in the elevation and floor-plane.
PART II. OF CONSTRUCTING SHIPS.
THE pieces by which this complicated machine, a ship, is framed, are joined together in various places, by scarfing, rabitting, tenanting, and scoring. See those articles.
During the construction of a ship, she is supported in the dock, or upon a wharf, by a number of solid blocks of timber placed at equal distances from and parallel to each other, as may be seen in the article LANCHING; she is then said to be on the stocks.
The first piece of timber laid upon the blocks is generally the keel: we say generally, because, of late, a different method has been adopted in some of the royal dock-yards, by beginning with the floor-timbers; the artists having found that the keel is often apt to rot during the long period of building a large ship of war. The pieces of the keel are scarfed together, and bolted, forming one entire piece, AA, which constitutes the length of the vessel below. At one extremity of the keel is erected the stem. It is a strong piece of timber incurved nearly into a circular arch, or, according to the technical term, compassing, so as to project outwards at the upper-end, forming what is called the rake forward. In small vessels this is framed of one piece; but in large ships it is composed of several pieces scarfed and bolted together, as expressed in the explanation of fig. 3. and in those terms separately. At the other extremity of the keel is elevated the stern-post, which is always of one entire straight piece. The heel of it is let into a mortise in the keel, and having its upper end to hang outwards, making an obtuse angle with the keel, like that of the stem: this projection is called the rake abaft. The stern-post, which ought to support the stern, contains the iron-work, or hinges of the rudder, which are called gogings, and unites the lower-part of the ship's sides abaft. See the connection of those pieces in the Elevation, fig. 1.
Towards the upper-end of the stern-post, and at right angles with its length, is fixed the middle of the wing-transom, where it is firmly bolted. Under this
is placed another piece parallel thereto, and called the deck-transom, upon which the after-end of the lower-deck is supported. Parallel to the deck-transom, and at a proper distance under it, another piece is fixed to the stern-post, called the first transom; all of which serve to connect the stern-post to the fashion-pieces. Two more transoms, called the second and third, are also placed under these, being likewise attached to the fashion-pieces, into which the extremities of all the transoms are let. The fashion-pieces are formed like the other timbers of the ship, and have their heels resting on the upper-part of the kelson, at the after-extremity of the floor-ribands.
All these pieces, viz. the transoms, the fashion-pieces, and their top-timbers, being strongly united into one frame, are elevated upon the stern-post; and the whole forms the structure of the stern, upon which the galleries and windows, with their ornaments, are afterwards built.
The stem and stern-post being thus elevated upon the keel, to which they are securely connected by knees and arched pieces of timber bolted to both; and the keel being raised at its two extremities by pieces of dead-wood, the midship floor-timber is placed across the keel, whereto it is bolted through the middle. The floor-timbers before and abaft the midship-frame are then stationed in their proper places upon the keel; after which the kelson, which, like the keel, is composed of several pieces scarfed together, is fixed across the middle of the floor-timbers, to which it is attached by bolts driven through the keel, and clinched on the upper-part of the kelson. The futtocks are then raised upon the floor-timbers, and the hawse-pieces erected upon the cant-timbers in the fore-part of the ship. The top-timbers on each side are next attached to the head of the futtocks, as already explained in Part I. The frames of the principal timbers being thus completed, are supported by ribands. See RIBANDS.
The
The ribs of the ship being now stationed, they proceed to fix on the planks, of which the wales are the principal, being much thicker and stronger than the rest; as is represented in the MIDSHIP-FRAME. The harpins, which may be considered as a continuation of the wales at their fore-ends, are fixed across the hawse-pieces, and surround the fore-part of the ship. The planks that inclose the ship's sides are then brought about the timbers; and the clamps, which are of equal thickness with the wales, fixed opposite to the wales within the ship: these are used to support the ends of the beams, and accordingly stretch from one end of the ship to the other. The thick-stuff, or strong planks of the bottom within-board, are then placed opposite to the several scars of the timbers, to reinforce them throughout the ship's length. The planks employed to line the ship, called the ceiling, or foot-waling, is next fixed in the intervals between the thick-stuff of the hold. The beams are afterwards laid across the ship to support the decks, and are connected to the side by lodging and hanging knees; the former of which are exhibited in their proper stations in Plate LXXXVIII. F. and the hanging ones, together with the breadth, thickness, and position of the keel, floor-timbers, futtocks, top-timbers, wales, clamps, thick-stuff, planks within and without, beams, decks, &c. are seen in the MIDSHIP-FRAME.
The cable-bits being next erected, the carlings (A), and ledges (B), which are represented in Pl. LXXXVIII. are disposed between the beams to strengthen the deck. The water-ways are then laid on the ends of the beams throughout the ship's length, and the spirketting fixed close above them. The upper-deck is then planked, and the string placed under the gunnel or planchee in the waist. The disposition of those latter pieces on the timbers, viz. the water-ways, spirketting, upper-deck, string, and gunnel, are also represented in the MIDSHIP-FRAME.
They proceed next to plank the quarter-deck and forecastle, and to fix the partners of the masts and capsterns with the coamings of the hatches. The breast-hooks are then bolted across the stem and bow within-board; the step of the fore-mast placed on the kelson; and the riders, exhibited in the MIDSHIP-FRAME, fayed on the inside of the timbers to reinforce the sides in different places of the ship's length. The pointers, if any, are afterwards fixed across the hold
diagonally to support the beams; and the crotches stationed in the after-hold to unite the half-timbers. The steps of the main-mast and capsterns are next placed; the planks of the lower-decks and orlop laid; the navel-hoods fayed on the hawse-holes; and the knee of the head, or cutwater, connected to the stem. The figure of the head is then erected, and the trail-board and cheeks are fixed on the sides of the knee.
The taffarel and quarter-pieces, which terminate the ship abaft, the former above and the latter on each side, are then disposed; and the stern and quarter galleries framed and supported by their brackets. The pumps, with their well, are next fixed in the hold; the timber-boards laid on each side of the kelson; and the garboard strake fixed on the ship's bottom next to the keel without.
The hull being thus fabricated, they proceed to separate the apartments by bulk-heads, or partitions; to frame the port-lids; to fix the cat-heads and chest-trees; to form the hatchways and scuttles, and fit them with proper covers or gratings. They next fix the ladders, whereby to mount or descend the different hatchways; and build the manger on the lower-deck, to carry off the water that runs in at the hawse-holes when the ship rides at anchor in a sea. The bread-room and magazines are then lined; and the gunnel, rails, and gangways, fixed on the upper part of the ship. The cleats, kevels, and ranges, by which the ropes are fastened, are afterwards bolted or nailed to the sides in different places.
The rudder, being fitted with its irons, is next hung to the stern-post; and the tiller, or bar, by which it is managed, let into a mortise at its upper-end. The scuppers, or leaden tubes, that carry the water off from the decks, are then placed in holes cut through the ship's sides; and the standards, represented in the MIDSHIP-FRAME, bolted to the beams and sides above the decks to which they belong. The poop-lanthorns are last fixed upon their cranes over the stern; and the bilge-ways, or cradles, placed under the bottom, to conduct the ship readily into the water whilst lanching.
As the various pieces which have been mentioned above, are explained at large in their proper places, it would have been superfluous to have entered into a more particular description of them here.
SHIP-MONEY, was an imposition charged upon the ports, towns, cities, boroughs, and counties of this realm, in the reign of king Charles I. by writs, commonly called ship-writs, under the great seal of England, in the years 1635 and 1636, for the providing and furnishing certain ships for the king's service, &c. which was declared to be contrary to the laws and statutes of this realm, the petition of right and liberty of the subject, by stat. 17 Car. I. c. 14. See Blackst. Comment. Vol. IV. p. 30.
SHIP-SHAPE, according to the fashion of a ship, or in the manner of an expert sailor; as, The mast is not
rigged ship-shape; Trim your sails ship-shape.
SHIPPING, a multitude of vessels. Thus we say, The harbour is crowded with shipping.
Defending SHIPS from Lightning. This is effected either by a continued conductor or chain, fixed to the top of the highest mast, and brought from thence into the sea. For the greater security, a chain or conductor may be affixed to each mast. See the articles ELECTRICITY and LIGHTNING.
Of late it has been observed, that a coating of lamp-black and tar is an effectual security against any stroke of lightning. But this acts not in the way of a conductor,
(A) These are short pieces of timber ranging fore and aft, from one of the deck-beams to another, into which their ends are scored: they are used to sustain and fortify the smaller beams of the ship.
(B) These are certain small pieces of timber placed athwart-ships, under the decks of a ship, in the interval between the beams; as exhibited in the representation of the deck, Plate LXXXVIII.