of the line A F, 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 out-lines of 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 knucke-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 A F, to which they are all parallel.
1st R^d. 2d R^d. 3d R^d. 4th R^d. The diagonal ribbands abaft the
midships.
_t_, _u_, _x_, _y_. The same ribbands expressed in the fore-body.
It has been remarked above, that the horizontal plane is composed of
water-lines and ribbands; 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 curves of the lower ones are usually parallel.
HORIZONTAL PLANE. Plate I.
B A C. The line of the ship’s length, passing through the middle of the
stem and stern-post.
B. The upper-end of the stern-post.
C. The upper-end of the stem.
B F. The length of the rake abaft.
D W X. The top-timber-breadth-line, or the line which limits the breadth
of each top-timber.
D F. The breadth of the aftmost timber at the taffarel.
B K. The wing-transom.
B L P. The horizontal curve of the deck-transom.
M M. The horizontal curve, or _round-aft_, of the first transom.
M N. The horizontal curve of the second transom: it is prolonged into a
water-line, N 8 7.
_k_ O. The horizontal curve of the third transom, which is also
prolonged into another water-line, O, _n_, U, _p_, Q.
_m_ O P. The plane of the fashion-piece, as canted aft.
⊕ W U. The plane of the midship-frame.
_a_, _b_, _c_, _d_, _e_, _f_, _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.
X X. The figure of the upper-rail of the head.
C Y. The projection of the knee of the head.
The Third horizontal ribband, 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 height of the wing transom: transfer this from the middle
of the line B A C, in the projection, to the point K in the
perpendicular A F, then will A K 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 C E, and extend the
other along the main-breadth-sweep ⊕ G, till it touches the
perpendicular A F parallel to C E: lay this distance upon the horizontal
plane from the point u in the line of the ship’s length, B A C, along
the plane of the midship-frame to the point ⊕; so shall the line ⊕ W U
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 B A C, in the
horizontal plane, to the top-timber breadth-line, 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 streight
lines in the elevation and projection; and thus the vertical curves of
the timbers are all exhibited on the projection, although they appear as
streight lines in the elevation and floor plane.
Before this article is closed, it may be necessary to remark, that the
various pieces represented in plate I. as well as the lines in the
draughts which have not been already defined, are copiously explained in
their proper places; as it would have been contrary to the plan of this
work to have given a more enlarged description of them here.
That the reader, however, might be better enabled to comprehend the
scope of this article, it was judged necessary to give a general sketch
of naval architecture itself; to collect into one point of view the most
material draughts by which a ship is constructed, and to describe, as
concisely as possible, the several parts of which they are composed.
The principal parts of a ship also, which are here reduced into a narrow
compass, will be represented at large in different places of this work,
to illustrate those explanations whither it may be necessary to refer,
in order to understand the subject more clearly. Thus the stern, the
quarter, the midship-frame, the bow and head, of a ship of 74 guns, are
exhibited on a scale of ¼ of an inch to a foot; by which all the
subordinate parts may be distinctly viewed, and their combination and
arrangement sufficiently understood.
ARMED-SHIP, _vaisseau armé en guerre_, a vessel occasionally taken into
the service of the government in time of war, and employed to guard some
particular coast, or attend on a fleet. She is therefore armed and
equipped in all respects like a ship of war, and commanded by an officer
of the navy, who has the rank of master and commander. All ships of this
sort are upon the establishment of the king’s sloops, having a
lieutenant, master, purser, surgeon, &c.
ASHORE, (from _a_ and _shore_) on the shore, or land, as opposed to
aboard.
A ship is said to be ASHORE, _echoué_, when she has run upon the ground,
or on the sea-coast, either by design or accident.
ASTERN, _au derriere_, (from _a_ and _steorn_, Sax.) any distance behind
a ship, as opposed to _a-head_, which is before her. Thus, when south is
_a-head_, or on the line to which the stem is directed, north will be
_astern_.
ATHWART, _par le travers_, (from _a_ and _twert_, Dan. transverse) when
used in navigation, implies across the line of the course; as, we
discovered a fleet at day-break standing _athwart_ us, i. e. steering
across our way.
ATHWART-HAUSE, the situation of a ship when she is driven by the wind,
tide, or other accident, across the fore-part of another. This phrase is
equally applied when the ships bear against each other, or when they are
at a small distance; the transverse position of the former to the latter
being principally understood.
ATHWART _the fore-foot_, a phrase employed to denote the flight of a
cannon-ball, as fired from one ship across the line of another’s course,
to intercept the latter, and compel her to shorten sail till the former
approaches near enough to examine her. The _fore-foot_ is the lower part
of the stem; so that the shot flying across it is said to be fired
_athwart the fore-foot_.
ATHWART-SHIPS, reaching across the ship, from one side to the other.
ATRIP (_trepor_, Fr. _trippen_, Dutch) is applied differently to the
anchor and the sails. The anchor is _atrip_, _derangée_, when it is
drawn out of the ground in a perpendicular direction, either by the
cable or buoy-rope. The top-sails are said to be _atrip_, when they are
hoisted up to the mast-head, or to their utmost extent.
AVERAGE, in commerce _avarie_, (_averagium_, Lat.) the accidents and
misfortunes which happen to ships and their cargoes, from the time of
their loading and sailing, till their return and unlading. It is divided
into three kinds. 1. The simple or particular _average_, which consists
in the extraordinary expences incurred for the ship alone, or for the
merchandise alone; such is the loss of anchors, masts, and rigging,
occasioned by the common accidents at sea; the damages which happen to
merchandises by storms, capture, shipwreck, wet, or rotting; all which
must be borne and paid by the thing that suffered the damage. 2. The
large and common average, being those expences incurred, and damages
sustained, for the common good and security, both of the merchandise and
vessels, consequently to be borne by the ship and cargo, and to be
regulated upon the whole. Of this number are the goods or money given
for the ransom of the ship and cargo; things thrown overboard for the
safety of the ship; the expences of unlading, or entering into a river
or harbour, and the provisions and hire of the sailors when the ship is
put under embargo. 3. The small averages, which are expences for towing
and piloting the ship out of, or into harbours, creeks, or rivers; one
third of which must be charged to the ship, and two thirds to the cargo.
AVERAGE is more particularly used for a certain contribution that
merchants make proportionably towards their losses. It also signifies a
small duty which the merchants, who send goods in another man’s ship,
pay to the master, for his care of them, over and above the freight.
Hence it is expressed in the bills of lading, paying so much freight for
the said goods, with damage and average accustomed.
AWEIGH, _a quitté_ (of _a_ and _weigh_) the state of the anchor when it
is drawn out of the ground in a perpendicular direction, by the
application of mechanical powers, as a capstern or windlass, to the
cable within the ship; so that aweigh is synonimous to _atrip_.
AWNING, _tendelet_, (from _aulne_, Fr.) a canopy of canvass extending
over the decks of a ship in hot weather, for the convenience of the
officers and crew, and to preserve the decks from being cracked or
split, _ebaroui_, by the heat of the sun: The awning is supported by a
range of light posts, called stanchions, which are erected along the
ship’s side on the right and left; it is also suspended in the middle by
a complication of small cords, called a crowfoot. See the article
CROWFOOT.
AZIMUTH-COMPASS, an instrument employed to discover the magnetical
azimuth or amplitude of any heavenly object. This operation is performed
at sea, to find the exact variation of the magnetical needle. The
compass will be described in its proper place: it is, however, necessary
here to explain the additional contrivance by which it is fitted to take
the magnetical azimuth, or amplitude of the sun or stars, or the
bearings of head-lands, ships, and other objects at a distance.
The brass edge, originally designed to support the card, and throw the
weight thereof as near the circumference as possible, is itself divided
into degrees and halves; which may be easily estimated into smaller
parts if necessary. The divisions are determined by means of a cat-gut
line stretched perpendicularly with the box, as near the brass edge as
may be, that the parallax arising from a different position of the
observer may be as little as possible.
There is also added an index at the top of the inner-box, which may be
fixed on or taken off at pleasure, and serves for all altitudes of the
object. It consists of a bar, equal in length to the diameter of the
inner-box, each end being furnished with a perpendicular stile, with a
slit parallel to the sides thereof; one of the slits is narrow, to which
the eye is applied, and the other is wider, with a small cat-gut
stretched up the middle of it, and from thence continued horizontally
from the top of one stile to the top of the other. There is also a line
drawn along the upper surface of the bar. These four, viz. the narrow
slit, the horizontal cat-gut thread, the perpendicular one, and the line
on the bar, are in the same plane, which disposes itself perpendicularly
to the horizon when the inner-box is at rest and hangs free. This index
does not move round, but is always placed on, so as to answer the same
side of the box.
The sun’s azimuth is known to be an angle contained between the meridian
and the center of the sun. When this is required, and his rays are
strong enough to cast a shadow, the box is turned about till the shadow
of the horizontal thread, or if the sun be too low, till that of the
perpendicular thread, in one stile, or the slit through the other, falls
upon the line in the index bar, or vibrates to an equal distance on each
side of it, the box being gently touched if it vibrates too far: at the
same time they observe the degree marked upon the brass edge of the
cat-gut line. In counting the degree for the azimuth, or any other angle
that is reckoned from the meridian, the outward circle of figures upon
the brass edge is used; and the situation of the index, with respect to
the card and needle, will always direct upon what quarter of the compass
the object is placed.
But if the sun does not shine out sufficiently strong, the eye is placed
behind the narrow slit in one of the stiles, and the wooden box turned
about till some part of the horizontal, or perpendicular thread appears
to intersect the center of the sun, or vibrate to an equal distance on
each side of it; smoked glass being used next the eye, if the sun’s
light is too strong. In this method another observer is necessary, to
note the degree cut by the nonius, at the same time the first gives
notice that the thread appears to split the object.
Plate II. fig. 20. is a perspective view of the compass, when in order
for observation; the point of view being the center of the card, and the
distance of the eye two feet.
A B. is the wooden box in which it is usually contained.
K. is a cat-gut line drawn from the inside of the box for determining
the degree upon the brass edge.
L, M, N, O. is the index bar with its two stiles, and cat-gut threads,
which being taken off from the top of the box, is placed in two pieces P
Q, notched properly to receive it.
The other parts of the figure, with their references, are explained in
the article COMPASS.
B.
BACK _of the post_. See the article STERN-POST.
To BACK _an anchor_, _empeneller_, to carry out a small anchor, as the
stream or kedge, ahead of the large one, by which the ship usually
rides, in order to support it, and prevent it from loosening, or _coming
home_, in bad ground. In this situation, the latter is confined by the
former, in the same manner that the ship is restrained by the latter.
_To BACK astern_, in rowing, _scier à culer_, is to manage the oars in a
direction contrary to the usual method, so as that the boat or vessel
impressed by their force, shall retreat, or move with her stern
foremost, instead of advancing.
_To BACK the sails_, is to arrange them in a situation that will
occasion the ship to retreat or move astern. This operation is
particularly necessary in narrow channels, when a ship is carried along
sideways by the strength of the tide or current, and it becomes
requisite to avoid any object that may intercept her course, as shoals,
or vessels under sail, or at anchor: it is also necessary in a naval
engagement, to bring a ship back, so as to lie opposite to her
adversary, when she is too far advanced in the line. See ABACK.
BACK-BOARD, a piece of board of a semicircular figure, placed
transversely in the after-part of a boat, like the back of a chair, and
serving the passengers to recline against whilst sitting in the
stern-sheets. See BOAT.
BACK-STAYS, _cale haubans_, (from _back_ and _stay_) long ropes reaching
from the topmast-heads to the starboard and larboard sides of the ship,
where they are extended to the channels: they are used to support the
top-masts, and second the efforts of the shrouds, when the mast is
strained by a weight of sail in a fresh wind.
They are usually distinguished into breast-back-stays and
after-back-stays; the intent of the former being to sustain the top-mast
when the force of the wind acts upon the ship sideways, or, according to
the sea-phrase, when the ship sails upon a wind; and the purpose of the
latter is to enable it to carry sail when the wind is further aft.
There are also back-stays for the top-gallant-masts, in large ships,
which are fixed in the same manner with those of the top-masts.
A pair of back-stays is usually formed of one rope, which is doubled in
the middle, and fastened there so as to form an eye, which passes over
the mast-head, from whence the two ends hang down, and are stretched to
the channels by dead-eyes and laniards. See DEAD-EYES, &c.
The figure of the back-stays, and their position, is exhibited in the
article RIGGING, to which the reader is further referred.
BADGE, _bouteille, fausse galerie_, in ship-building, a sort of
ornament, placed on the outside of small ships, very near the stern,
containing either a window, for the convenience of the cabin, or the
representation of it: it is commonly decorated with marine figures,
martial instruments, or such like emblems. See QUARTER.
To BALANCE, (_balancer_, Fr.) to contract a sail into a narrower
compass, in a storm, by retrenching or folding up a part of it at one
corner; this method is used in contradistinction to _reefing_, which is
common to all the principal sails; whereas balancing is peculiar to few,
such as the mizen of a ship, and the main-sail of those vessels, wherein
it is extended by a boom. See BOOM and REEF.
The BALANCE of the mizen, _fanon_, is thus performed: the mizen-yard is
lowered a little, then a small portion of the sail is rolled up at the
_peek_, or upper corner, and fastened to the yard about one fifth inward
from the outer end, or yard-arm, toward the mast. See MIZEN.
A boom-main-sail is balanced, after all its reefs are taken in, by
rolling up a similar portion of the hindmost, or aftmost lower-corner,
called the _clue_, and fastening it strongly to the boom, having
previously wrapped a piece of old canvas round the part (which is done
in both cases) to prevent the sail from being fretted by the cord which
fastens it.
BALLAST, _lest_, (_ballaste_, Dut. _ballastro_, Span.) a certain portion
of stone, iron, gravel, or such like materials, deposited in a ship’s
hold, when she has either no cargo, or too little to bring her
sufficiently low in the water. It is used to counter-ballance the effort
of the wind upon the masts, and give the ship a proper stability, that
she may be enabled to carry sail without danger of over-turning.
There is often great difference in the proportion of ballast required to
prepare ships of equal burthen for a voyage; the quantity being always
more or less, according to the sharpness or flatness of the ship’s
bottom, which seamen call the _floor_.
The knowledge of ballasting a ship with propriety, is certainly an
article that deserves the attention of the skilful mariner; for although
it is known that ships in general will not carry a sufficient quantity
of sail, till they are laden so deep that the surface of the water will
nearly glance on the extreme breadth amidships; yet there is more than
this general knowledge required; since, if she has a great weight of
heavy ballast, as lead, iron, &c. in the bottom, it will place the
center of gravity too low in the hold; and although this will enable her
to carry a great sail, she will nevertheless sail very heavily, and run
the risk of being dismasted by her violent rolling.
To ballast a ship, therefore, is the art of disposing those materials so
that she may be duly poised, and maintain a proper equilibrium on the
water, so as neither to be too _stiff_, nor too _crank_, qualities
equally pernicious; as in the first, although the ship may be fitted to
carry a great sail, yet her velocity will not be proportionably
increased; whilst her masts are more endangered by her sudden jerks and
excessive labouring: and in the last, she will be incapable of carrying
sail, without the risk of oversetting.
Stiffness in ballasting, is occasioned by disposing a great quantity of
heavy ballast, as lead, iron, &c. in the bottom, which naturally places
the center of gravity very near the keel; and that being the center
about which the vibrations are made, the lower it is placed, the more
violent will be the motion of rolling.
Crankness, on the other hand, is occasioned by having too little
ballast, or by disposing the ship’s lading so as to raise the center of
gravity too high, which also endangers the mast in carrying sail when it
blows hard: for when the masts lose their perpendicular height, they
strain on the shrouds in the nature of a lever, which encreases as the
sine of their obliquity; and a ship that loses her masts is in great
danger of being lost.
The whole art of ballasting, therefore, consists in placing the center
of gravity to correspond with the trim and shape of the vessel, so as
neither to be too high nor too low; neither too far forward, nor too far
aft; and to lade the ship so deep, that the surface of the water may
nearly rise to the extreme breadth amidships; and thus she will be
enabled to carry a good sail, incline but little, and ply well to the
windward. See the article TRIM.
BANIAN-DAYS, a cant term among common sailors, denoting those days on
which they have no flesh-meat: it seems to be derived from the practice
of a nation amongst the eastern Indians, who never eat flesh.
BANK, _banc, atterrissement_, (_banc_, Sax.) an elevation of the ground,
or bottom of the sea, which is often so high as to appear above the
surface of the water, or at least so little beneath it, as to prevent a
ship from floating over it: in this sense, bank amounts nearly to the
same as shallows, flats, &c. The shelves that abound with rocks under
water, are distinguished by other names, as reefs, ridges, keys, &c.
An exact knowledge of the banks, their extent, and the different depths
of water in which they lie, constitutes a very essential portion of the
science of a pilot, or master of a ship. If the vessel be large, and
draws much water, great attention will be necessary to avoid them. If,
on the contrary, she is small, the same banks afford a sure asylum,
where she may brave the largest ships, which dare not follow her to so
dangerous a retreat. Many small vessels have eluded the pursuit of a
superior enemy by means of this hospitable barrier.