SHIP-BUILDING. 
136 
also abaft the after-port, to the transoms: these considered 
make the length of the gun-deck 180 feet. 
Draw therefore, as in sheer-plan, (PI. I ) a straight line, 
which represents the upper edge of the keel, and in naval 
ships the upper edge of the rabbet (East India ships and 
merchant-ships in general have the rabbet in the middle of 
the keel), leaving under this line sufficient space for the main 
and false keels, scale, and half-breadth plan. Upon this 
line square up a perpendicular towards the right hand, leav¬ 
ing a sufficient space to represent the head, and ca l it the 
foremost-perpendicular; then, at 22b inches abaft it, square 
up the after-perpendicular, which is 180 feet, by one-eighth 
of an inch to a foot, or the length on the gun-deck, from 
the aft-side of the rabbet of the stem to the fore-side of the 
rabbet at the stern-post Below the upper edge of the keel, 
and parallel thereto, set down two feet for the main and false 
keel, and under it draw the scale of equal parts, of one-eighth 
of an inch to a foot, and from this scale set off all the fol¬ 
lowing dimensions. Observe, draughts in general are drawn 
from a scale of one quarter of an inch to a foot, but this to 
one-sixteenth. 
The length between the foremost and aftermost perpendi¬ 
culars, iu merchant-ships, is given from the aft-side of the 
•tern-post, at the height of the wing-transom, to the fore-side 
of the stem, at the same height. 
The stem, or fore-boundary of the ship, may now be 
drawn, and a segment of a circle for its lower part has long 
been considered as the best form for dividing the fluid ; 
therefore, fix its centre so that the aft-side of the rabbet 
(which is in the middle of the stem, towards the upper part) 
may intersect the foremost perpendicular at the height of the 
gun-deck thus, set aft from the foremost perpendicular, as 
in Pi. I. upon an horizontal line, 24 feet above the upper edge 
of the keel, 24 ft. 3 in.; and from thence, as the centre, 
draw an arc of a circle from the upper edge of the keel-line, 
and another arc 18 inches before it, from the same centre; 
then will the moulding, or fore and after-sides of the stem, 
be represented: sweep likewise the rabbet, as in PI. I.; then 
set up 36 feet for the height of the head of the stem, and at 
that height set forward 15 inches from the foremost-perpen¬ 
dicular ; from thence draw a faint curve, to intersect with 
the foremost segment, and the fore-part of the stem will be 
shewn: continue upwards another parallel thereto, and the 
aft-side or whole stem is completed, except the lower end or 
boxing, which will be determined hereafter. 
The stern-post, or after-boundary under water, may be 
next drawn; thus, set up from the upper edge of the keel¬ 
line 26 ft. 10 in., which is the upper side of the wing-tran¬ 
som at the after-perpendicular, and upon that line set aft 
from the perpendicular 1 ft. 10 in., and upon the upper edge 
of the keel, six inches before the after-perpendicular; then a 
line drawn through these points will represent the aft-side of 
the stern-post; another line, drawn at fourteen inches before 
the aft-side of the stern-post, at the wing-transom, and at 
two feet one inch on the upper edge of the keel, will be the 
aft-side of the rabbet; and another line parallel four inches 
before it (or at the thickness of the bottom plank) is the fore¬ 
side of the rabbet, which will intersect the after-perpendicu¬ 
lar of the gun-deck. Thus far the stern-post at present. 
Having fixed on the length of the gun-deck, the next prin¬ 
cipal dimension to be considered is the main-breadth, and 
this, in ships of war in general, is about three-elevenths of 
the said length for their moulded breadth, and in merchant- 
ships about three-twelfths of their length ; excepting cutters 
and smaller vessels. The moulded breadth given in PI. I. of 
th£ 74-gun ship, is 48 feet. 
Now as to the best breadth and its best situation, those 
who wduld' diminish the breadth have alleged, and truly, 
that a narrow vessel meets with less resistance in passing 
through the water, and by increasing in length, the vessel 
will drive less to leeward. On the contrary, a ship’s being 
broader at the line of floatation will admit of being narrower 
on the floor, particularly at the fore and after parts; and by 
being broader it can carry more sail, and more readily rise 
upon the waves than a narrow one. 
It is agreed that judiciously placing the midshiphend is 
of the utmost consequence in the construction of ships’ 
bodies; in the Plate it is placed at 69 feet abaft the 
foremost-perpendicular, consequently this is the broadest part 
of the ship, called the midships, or dead-flat, known by this 
character ®, and where all the heights in midships are set up. 
The dead-flat in Plate I. is a single timber, and the per¬ 
pendicular, marked ©, the middle of it: therefore, for the 
joints of the annexed frames set off before ®, two feet nine 
inches for the joint of (A), and two feet nine inches abaft © 
for the joint of ( 1 ), square up perpendiculars from the upper 
edge of the keel; then from (A) continue setting off five 
feet six inches for the joints of frame B, C, D, to X, in the 
fore-body, and the same distance abaft ( 1 ; for the joints of 
frame (3), 2, 4, 6 , to 36 in the after-body, as shewn in 
Plate I. Now ©, (A), (1), (2), and (3), are called flats, as 
they are the timbers which are placed in the flat part of the 
ship amidships, have no bevellings, and consequently do not 
partake of the rising. 
The lower height of breadth is an imaginary line, not 
only to assist in the construction of the body, but a line 
confining the greatest breadths in the ship, all fore and aft, 
and should next be determined upon. Its height at © is 
21 feet 3 inches above the upper edge of the keel; and that 
the said height of breadth should be higher afore and abaft 
is only reasonable as a reserve, to be a support to the vessel 
when heeling by the pressure of the wind upon the sails; 
for when a ship is close-hauled by the wind, and lies much 
over, the weather side would lose much of the breadth, 
whereas, on the contrary, the lee-side would then gain con¬ 
siderably, and meeting with a greater resistance, be enabled 
to carry the greater sail; therefore forward at the rabbet of 
the stem its height is 29 feet, and abaft at the counter¬ 
timber 29 feet 6 inches; and all the heights between should 
form a (air curve, like the ticked line in the sheer-draught. 
Plate I. ° 
It may here be remarked, that flat-floored ships do not 
require their height of breadth to be raised so high forward 
and alt, for by their construction they are stiffer under sail, 
and carry their weight of cargo low down. 
The body below the lower height of breadth may now be 
formed, as the frames or bends, when put together, and the 
joint placed to the fore-mentioned perpendiculars, the sides 
of every port will be formed so as to cut none of the prin¬ 
cipal timbers, and are so disposed as to weaken the ship as 
little as possible. 
The half-breadth plan must be next drawn: draw a 
straight line as in Plate I., the whole length of the ship, and 
parallel to the upper edge of the keel, w'hich line will repre¬ 
sent the middle line of the ship, at any height passing fore 
and aft, or lengthwise; observing to keep the said middle 
line sufficiently below the scale, so as to admit of the main 
half-breadth line coming clear of it. 
Then square down from the sheer-plan all the perpendi¬ 
culars or joints of the frame-timbers, to the middle line of 
the half-breadth plan, and likewise the foremost and after- 
perpendicular. The main half-breadth liue may now be 
drawn, by setting-off from the middle line in the plan the 
following half-breadths at each respective timber ; thus, at 
©, 24 feet; at F, 23 feet Ilf inches; at H, 23 feet 11 
inches; at K, 23 feet 1 0 inches; at M, 23 feet 5§ inches; at 
O, 23 feet; at Q, 22 feet 2 inches; at S, 20 feet 4 inches; 
at U, 17 feet 6 inches; at X, 12 feet 6 inches; and to end 
this line at the fore part, let the height of the breadth-line in 
the sheer-plan, where it intersects the aft-side of the rabbet at 
the stem, be squared down to the middle line in the half¬ 
breadth plan, and likewise the fore part of (he stem: upon 
the lines last squared down, set off the half-siding of the 
stem from the middle line and parallel (hereto, which is ten 
inches; then, with compasses, take the thickness of the 
boltom plauk, which is four inches, and describe (he rabbet 
of the stem by the triangle shewn in the half-breadth plan; 
from thence a fair curve line drawn through the half-breadths 
set off, forms the half-breadth line to ©. In the same manner 
set off the half-breadths abaft ©, and draw in (he remainder 
set 
