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Thus, having gained a few of the first leading principles, we will proceed to show their utility in constructing what is called the sheer-draught: and the necessity of dividing the sheer-draught into three distinct plans will be evident by inspection.

First. The sheer-plan, called, in general architecture, the plan of elevation. This is a section of the ship made by a vertical or perpendicular plane, passing through the middle line of the keel, stem, and stern-post, throughout the whole length of the ship.

Secondly. The half-breadth plan, called by architects the ground-plan. This plan consists of an horizontal view of the half-breadths of the water-lines, ribbands, main and top-breadths, half-breadth of the rising, ditto by longitudinal curves, by which the several breadths are limited, and, as they would appear to the eye, placed directly over, and looking down on the aforesaid sections, whether cut ting the solid (supposing a ship a solid body) either by horizontal, diagonal, or sheer planes.

Ft. L. Guns. Ft. I. Guns. Ft. I. 18

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ment; the said ship having been really built, and found to answer every expectation. Now, in the clearest manner possible, we will endeavour to point out the utility of these plans, in the construction of the various curves that form the body of a ship in their different points of view, whether transverse or longitudinally, as on the several plans they will present themselves in very different directions; for, although the horizontal water-lines are represented by curves in the halfbreadth plan, they are straight lines in sheer and body plan, and so likewise the appearance of the timbers; for, although they present themselves as vertical curves in the body plan, they appear as straight lines in the sheer and half-breadth plan; these premises being well understood, we may proceed to the construction of these several plans; and first, in the

Sheer plan, draw the stem keel, sternpost, &c. thus: draw a straight line that shall represent the upper edge of the rabbit of the keel, more than the main halfbreadth of the vessel above the lower edge of the paper; then to your rightThirdly. The body-plan, or plan of pro- hand square up the foremost perpendicujection, are the transverse sections of the lar, allowing room to represent the head. ship, at the joint of every frame-timber, Now, as the limits of our design will not showing the half breadth of each frame- admit of our continuing the dimensions of timber, as it stands perpendicularly to the all the before mentioned ships; and as two former plans: hence, the frames con- only one can be selected to form the sheer tained between, or the midship, that draught, the 74 gun ship is made choice being the broadest frame, and the stem, of, as being, of all vessels, the most handare represented on the right-hand side, some, and arrived to the greatest perfecand the frames at aft on the left hand tion in the construction; therefore set aft of the middle line in the body-plan are re- 180 feet from the foremost perpendicular, spectively called the fore and after body. and square up another, calling it the after It may be necessary to add, that in all perpendicular, which gives the length of these plans only one half of the ship is re- the gun-deck, or first principal dimension. presented, as each side must be supposed Then square up another perpendicular, to be exactly alike, and that they must be 69.0 feet abaft the foremost one, which is very accurately drawn to the dimensions the midship perpendicular marked thus given, which have all been examined by, and called dead flat. Much has been proper calculations, submitted to the most precise scrutiny, and the results have actually stood the best test, that is, experi

said concerning the situation of this transverse section, it being the broadest part of the ship, and containing the greatest

area of surface; its judicious disposal will certainly facilitate the velocity of the vessel. All have agreed, and experience has confirmed it, that its position should always be before the middle of the vessel's length, or its centre of gravity. The French say, about the length of the vessel from aft, and nearly there may be its best position, as vessels, in general, have been found much better constructed since the midship has been fixed nearer the stern.

Set up from the upper edge of the keel, or rabbit, the height of the under side of the gun-deck, at the middle line, or middle of the ship, which is 24 feet 5 inches at the foremost perpendicular, 22 feet at, and 25 feet 4 inches up the after perpendicular; having these three heights, the hang, or sheer of the deck, may be obtained, all fore and aft, by a drawing-bow, the lath of which is pressed by its screws, until it intersects the said heights set up, as this is supposed to produce the arch of a circle equal to the sheer of the deck; the upper side of the deck is then shown, by a line drawn 4 inches above, and parallel to its under side. Then, when the under side of the gun-deck intersects the foremost perpendicular, set forward 4 inches for the rabbit of the stem, and 7 inches afore the rabbit, for the fore-side of the stem, and 7 inches abaft the aft-side of the rabbit, for the aft-side of the stem, the whole making 18 inches, the moulding of the stem; then with a radius equal to 24 feet, half the moulded breadth, sweep an arch which will form the aft-side of the stem below the gun-deck, intersecting the line drawn for the upper edge of the rabbit of the keel; then lengthen the radius to the fore-side of the stem, and sweep a circle parallel to the aft-side; then sweep in the aft-side of the rabbit, by the radius 24 feet, keeping the centre the same height above the upper edge of the rabbit on the keel; as there the aftside of the rabbit on the stem at the gundeck, and the rabbit of the keel, intersect each other, by carrying the centre 7 inches before the first; then describe the aft-side of the rabbit, and by opening the radius 4 inches more, the fore-side of the rabbit will be parallel to the aft-side, and the stem and rabbit shown below the lowerdeck, except the boxing, or keel, which will be determined on hereafter; then set up from the upper edge of the rabbit of the keel, on the foremost perpendicular, 36 feet, the height of the upper part of the stern, and draw a horizontal line upon this line before the perpendicular; set off 15 inches, which is what the stem rakes

forward at the head; thence draw a straight line, or one a little curving, to break in fair with the back of the foremost sweep, at gun-decks, and the fore-side of the stem is complete; then draw another, 18 inches from, and parallel to, the foreside, and the aft-side will be drawn ; then by the same curve the rabbit may be continned up on the fore-side, to the head of the stem, as the aft-side of the rabbit may not be drawn higher than the under side of the wall.

Proceed to draw in the stern-post thus: before the after perpendicular on the upper edge of the keel, set 7 inches; then set up the after perpendicular 27 feet from the upper edge of the keel, and draw a horizontal line, which is the upper side of the wing transom on that line abaft the perpendicular, set off 23 inches; then a' straight line drawn through those two spots will represent the aft-side of the stern-post; then from the aft-side of the stern-post, set forward on the upper side of the keel 2 feet 1 inch, and at the upper side of the wing transom 13 inches: a straight line drawn through these two spots will be the aft-side of the rabbit, and another line 4 inches parallel before it, will be the fore-side of the rabbit, which will intersect the perpendicular at the gun-deck. The stern-post, thus far described, would be sufficient at present; but to complete it, set up 2 feet 8 inches above the upper side of the wing transom, and continue upwards the aft-side; then, on a line parallel to the under side of the deck, at that height set forward 20 inches, and from the aft-side 3 feet upon the upper side of the keel, a line, drawn through those spots and the stern-post, will be represented from the head downwards. Draw another line before the fore-side of the post, on the keel, 16 inches, and at the under side of the deck transom 13 inches, and the fore-side of the inner post will be likewise represented. Thus we have the extremities of the ship below the main-breadth.

The height of breadth-lines are next to be drawn on the sheer plan, and there they determine the height of the broadest part of the ship, at each transverse section or timber; that nearest the keel is called the lower height of breadth, and the one above the upper height of breadth. The lower height of breadth in the midships generally is placed midway between the ports and the load-water line in naval ships, and rather above the loadwater line in merchant-ships; its quick rise forward and aft is highly requisite for

preserving a greater breadth above the load-water line, to assist and relieve the ship in her pitching and rolling motions in a heavy sea, lifting her forward, and making her lively, as the seamen call it. In order to set up the height of breadthlines, it is necessary that the stations of several of the timbers should be set off between the perpendicular at , and the stem forward, and the stern-post abaft: here the timber and room, or room and space, must be determined, which is the diameter between the moulding edges, or joints of every two timbers, and an interval of two or more inches between them; for here it may be observed, that in moulding the timbers, either before or abaft this joint or station, the moulds are made to the same line, as they are supposed to adjoin each other; but this method could not be true, supposing the timbers to be separated some distance apart; and it must be here also further observed, it being of the utmost consequence to the strength of the ship, that all the frame timbers should be preserv. ed whole, and not cut or wounded by the ports, as the timbers appointed to make the sides of ports should run up to the top of the side, and are to be united or framed together into bends, before they are gotten up into their places in the ship: thus, those intended to make the sides of ports are called frame-timbers; and those cut off under the ports, or between the frames, are called filling timbers, the third futtocks of which, to increase the strength, should run up to the under-sides of the ports, if possible.

The room and space of this ship is 2 feet 9 inches, consequently the distance of every frame joint is 5 feet 6 inches; and it is at each of these stations that perpendiculars from the keel are drawn in the sheer plan; the timbers before are alphabetically named A, B, C, &c.; and those abaft, or dead flat, numerally 1, 2, 3, &c. The timbers adjoining, which have no rising, are distinguished thus (A) (B), or (1) (2), and are likewise called flats.

In this ship is a single timber, although it has been before observed this single timber is sometimes placed near the steps, or gangway. Observe, this single timber is introduced to change the bodies, as that before it is called the forebody, so that abaft it is called the afterbody but this is not all; the floors in the fore-body are placed on the fore-side of the joint, consequently their moulding edge is on their aft-side, and the floors

in the after-body are placed on the aftside the joint, and their moulding edge is on their fore-side; therefore, in both bodies they become under bevellings; hence the necessity of this single timber to effect this change, or two floors would come together at the turn of the body, and the joint at their heads not strengthened by this intermediate shift of timber.

Now, as we do not mean to square up perpendiculars at the joint of every frame timber, we shall make use of as many as will suit our purpose in delineating the sheer plan. Therefore, set before the perpendicular 19 feet 3 inches, and then square up from the upper edge of the keel a perpendicular, and under it mark F, as that is the station for frame F; then before F square up perpendiculars at 11 feet distant, marking under that next F, K, the next O, and the foremost one S. Then abaft the perpendicular set off twenty 24 feet 9 inches, and then square up a perpendicular, and mark under it 6, as that will be the station for frame 6; then abaft this perpendicular set off 16 feet 6 inches five times, and square up perpendiculars at each station, marking that next abaft 6, 12, the others in succession 18, 24, 30, and the after one 36. These perpendiculars, or stations, are always referred to by those names hereafter.

Above the upper edge of the rabbit of the keel set up upon the foremost perpendicular 29 feet, the height of breadth at the stem, as both heights of breadths are terminated at one place quite forward and aft; next set up at S 24 feet 2 inches; at O 22 feet 8 inches; at K 21 feet 10 inches; at F 21 feet 3 inches; at 21 feet 3 inches; at 6, 21 feet 34 inches; at 12, 21 feet 4 inches; at 18, 21 feet 6 inches; at 24, 22 feet 4 inches; at 30, 23 feet 9 inches; at 36, 26 feet 5 inches; and the after perpendicular 27 feet 10 inches. Then an elliptical curve drawn through those heights will show the lower height of breadth all fore and aft.

The rising line is the next curve to be drawn in the sheer plan, which, in a ship of this construction, gives the heights of the centres of the floor-sweeps, by the which curves the shape of the timbers at and near the floor-heads are formed in the body plan; thus, set up, as before, at K 21 feet 4 inches; at F 14 feet 7 inches; at 11 feet 6 inches; at 6, 12 feet; at 12, 14 feet; at 18, 17 feet 6 inches; at 24, 24 feet 11 inches.

Then an elliptical curve drawn through those heights will determine the centre

heights of the floor-sweeps; and although these lines may be termed imaginary lines, and not wanted in finishing the fabric, the necessity of drawing these lines, with their connected half breadths, &c. will appear, when we insist upon the nicety required in the formation of every line used in ship building; and by thus representing them, the draftsman, or constructor, avails himself of an opportunity of observing that the said lines make fair curves. We said above, that the rising line in a ship of this construction gave the heights of the centres for forming the floor-sweeps; but in full-built ships, or merchant ships in general, this rising line gives the rising or lifting of the floors towards their heads, above which one radius is given for limiting their curves, and from this very line the whole construction or form of the body at this place is given. Now, in the formation of this line, no undeviating rule is given; therefore, to construct it, a general knowledge of the formation of various bodies of different vessels is absolutely necessary. But what follows may be invariably observed, that is, the lifting of this line on the sheer plan, and narrowing it on the half-breadth plan, will procure velocity and less capacity: while lowering it on the sheer plan, and continuing its midship part parallel with the keel, and augmenting its breadth on the half-breadth, and continuing it in midships parallel with the middle line, will produce a full, or burthensome vessel; but then a vessel on this construction will not sail; hence the judgment required in constructing this part of the ship can only be acquired by practice.

Now the main half-breadth, and the half-breadth of the rising of this ship, may be drawn in the half-breadth plan thus, draw a straight line, parallel to and as much below the upper side of the keel, in the sheer plan, as will admit of the depth of the keels a scale of feet and inches, by which the whole is to be drawn, and rather more than the main-half breadth at, and this line will represent the middle line of the half-breadth plan, and is so called: then square down upon this line the several perpendiculars from the sheer plan, and it will also there represent the several timbers as sections crossing the timbers in the sheer plan at right angles.

Then for the main half-breadth set up from the middle line, for S, 20 feet 4 inches; at 0, 23 feet; at K, 23 feet 10 inches; at F, 23 feet 11 inches; at, 24 feet; at 6, 23 feet 11 inches; 12, 23

feet 11 inches; at 18, 23 feet 8 inches; at 24, 22 feet 9 inches; at 30, 20 feet 10 inches; and at 36, 17 feet 9 inches. Draw

a

curve through these several halfbreadths, and the main half-breadth line will be described, except the fore and after parts. Permit us here to observe, the best method for drawing this and all other lines partaking of the nature of curves, is by elliptical moulds; or, what is better, when they are of any length, is by a thin pliable batton, confined down to the several spots, or dimensions, by square pieces of lead, about three or four ounces in weight; because by this last method the draughtsman has an opportunity of observing the fairness, or correctness of the line before he draws it. readers will excuse this particular description, because it need not be repeated, as all lines hereafter are supposed to be drawn in the same manner.

Our

Now, to end the main half-breadth forward, proceed as follow: when the height of breadth cuts the fore-part of the rabbit on the stem, square it down to the middle line of the half-breadth plan, by taking its nearest distance from the adjoining perpendicular, and setting off that distance in the same manner from the same perpendicular on the middle line in the half-breadth plan, and there square up a line; then set up on it 10inches, the half-siding, or thickness, of the stem at that place, from the middle line then, with compasses opened to 4 inches, the thickness of the plank of the bottom, sweep aft from the half-thickness of the stem an arch; then with a radius equal 26 feet 6 inches will finish the fore-part of the main half-breadth line; from the following centre draw a line at 4 feet 4 inches below, and parallel to the middle line of the half-breadth plan under timber O, and from timber O set forward 20 inches, and square it down to the line last drawn, and its intersection will be the centre required; then with radius 26 feet 6 inches, sweep the segment of a circle from timber S, till it will intersect the back of the arch at the thickness of the bottom plank; thus the main halfbreadth line is completed, except the after end, which must be finished hereafter.

Next set off the half-breadth of the rising, which limits the distance of the centres of the floor-sweeps from the middle line on their respective heights in the body plan. Set up from the middle line of the half-breadth plan, at timber K, 2 feet 9 inches, at F, 7 feet 2

inches; at, 8 feet 6 inches; at 6, 8 feet 5 inches; at 12, 7 feet 6 inches; at 18, 5 feet 3 inches; and at 24, 8 inches; then drawing a curve through those spots, the half-breadth of the rising will be

seen.

We may now proceed to drawing the vertical curve appearance those several timbers will form, below the lower height of breadth line in the body plan. Continue aft the upper edge of the rabbit of the keel line, and on it square up a line about 40 feet abaft the after perpendicular, and call this the middle line; then, at 24 feet distance, which is the main half breadth at midships on each side the middle line, square up a side line; then, within the boundaries of, on the right hand, will be delineated the several timbers which compose the fore-body; and within, on the left, those of the after-body.

Now transfer the several heights of the lower height of breadth line from the sheer plan at and before, and set them up the side line in the fore-body plan, drawing horizontal lines across at those heights to the middle line; then take the several main half-breadths from, and forward from the middle line of the halfbreadth plan, and set them off from the middle line on their corresponding heights of breadth last drawn in the forebody plan, and the utmost limits, or main breadth, of each timber will be shown.

Now draw another curve in the half breadth plan which shall be the radius or length, whereby portions of circles are swept, to form the shape of the body some distance below the main breadth. Set up from the middle line at in the half breadth plan 18 feet 9 inches; at F, 18 feet; at K, 17 feet; at 0, 15 feet 8 inches; at S, 18 feet 11 inches; at 6, 18 feet 9 inches; at 12, 18 feet 7 inches; at 18, 17 feet 2 inches; at 24, 15 feet 3 inches; at 30, 12 feet 3 inches; and at 36, 7 feet. Draw a fair curve through these spots, and the length of all the sweeps may be obtained; then transfer the length at, and the timbers before it, and set them off with the half breadth of their respective timbers on their correspond. ing height of breadth lines in the forebody plan, sweeping an arch about 7 feet below each height.

In the same manner transfer the heights for the centres of the floor-sweeps, from the sheer to the body-plan, and on those heights, from the middle line, set off the corresponding rising half breadths, their intersections between the centres, from

which each floor may be swept by the foliowing radii, without its rising half breadth, the radius atis 11 feet, and what this is above the upper edge of the keel is called the dead rising. The radius at F is 13 feet 7 inches; at K, 20 feet 3 inches. Then, with a curved mould, sometimes called a reconciling sweep, (as in some bodies it might be a portion of a circle,) placed so as to cut the back of the lower and floor-sweeps, the timber will be represented almost to the keel, and so may the other timbers as far as K; then, to complete them to the keel, set off the half siding of the keel, which is 9 inches, on each side the middle line in the body-plan, below the line for its upper edge, and draw a line on each side parallel to the middle line; then with compasses, opened to four inches, make two arcs, on each side, from the upper side of the keel, to cross each other towards the middle line; draw a straight line from the upper, and another from the lower side of the rabbit, to intersect the arcs at equal angles, and the rabbit of the keel will be shown. Then a straight line, or a mould a little hollow, (sometimes called floor-hollow,) placed to the siding of the keel at the upper edge of the rabbit, and to cut the back of the floorsweep, the timbers as far as K may be completed as the keel.

Now, as the other timbers approach the stem in the fore body, and those towards the stern post in the after body differ in shape materially from those timbers near the midships, it will be necessary to draw in several horizontal or water lines, as they are called; for supposing the ship was floating on an even keel, and in an upright position, sections from side to side would thus be formed by the water. Here also we would show that every attention has been paid, and notice to our readers that vessels, in general, are found in their best sailing trim when they incline abaft from one to two feet, and sometimes more, particularly sharp constructed bodies, and that the upper one, being the load-water line, is drawn to this inclination, and that the several water lines below it have been kept parallel thereto; thus in the common mode of representing the water lines, in the half breadth plan, their correct shape at those places was not accurately ascertained; and as it is not necessary they should be so drawn, horizontal lines are more preferable, and more useful; therefore draw in the sheerplan five horizontal lines, above the upper edge of the keel, 3 feet 8 inches asunder.

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