round turn. If the larboard cable, lying across the stem, points out on
the starboard side, while the starboard cable at the same time grows out
on the larboard side, there is a cross in the hause. If, after this, the
ship, without returning to her former position, continues to wind about
the same way, so as to perform an entire revolution, each of the cables
will be twisted round the other, and then directed out from the opposite
bow, forming what is called a round turn. An elbow is produced when the
ship stops in the middle of that revolution, after having had a cross:
or, in other words, if she rides with her head northward with a clear
hause, and afterwards turns quite round so as to direct her head
northward again, she will have an elbow. See the articles ELBOW and
RIDING.
HAUSE-HOLES, _ecubiers_, certain cylindrical holes cut through the bows
of a ship on each side of the item, through which the cables pass in
order to be drawn into, or let out of the vessel, as occasion requires.
They are represented by _d d_ in fig. 10. plate IV. being fortified on
each side by the
HAUSE-PIECES, a name given to the foremost timbers of a ship, whose
lower ends rest upon the knuckle-timber, or the foremost of the
cant-timbers. They are generally parallel to the stem, having their
upper ends sometimes terminated by the lower part of the beak-head, and
otherwise, by the top of the bow, particularly in small ships and
merchantmen.
HEAD, an ornamental figure erected on the continuation of a ship’s stem,
as being expressive of her name, and emblematical of war, navigation,
commerce, &c.
The heads which have any affinity to war or navigation, are in general
either historical, as referring to some of the deities or heroes of
antiquity; or allegorical, as alluding to some of the natural
consequences of battle, or the virtues most essential to a life exposed
to perpetual danger. Thus, in the former sense, they represent a
Neptune, an Alcides; a Mars, an Achilles; a Minerva, or a Jason; and in
the latter they produce a _Magnanime_, an Intrepid, a Revenge, or a
Victory.
The head of a ship however has not always an immediate relation to her
name, at least in the British navy. Various instances might be produced
to shew, that our artists, as it suits their conveniency or judgment,
can dispense with this supposed idea of propriety. Hence we sometimes
observe the place of a Jason supplied by a Medea; or a best of prey made
the representative of an illustrious lady. The same liberty of design
may therefore, with equal propriety, be allowed to symbolize the
successes of our arms, by a groupe of heterogeneous figures, of sundry
shapes and sizes, according to the artists opinion of their superiority
or subordination. Their attitude and situation, as well as their size,
must accordingly depend, in a great measure, on the space into which
they are to be crowded: for although the figures may be of equal
importance in themselves, yet as there is not room for them all, as
large as the life, on a ship’s head, it becomes expedient to diminish a
few, in order to give place to others. The emblems by which allegorical
figures are usually characterized in painting, poetry, and sculpture,
are not always thought necessary in a work of this kind, nor even the
postures in which these figures are exhibited. And indeed, if we reflect
with how much labour and application the workman has endeavoured to fill
up every vacancy with some little figure of a convenient form and size,
we ought rather to admire his ingenuity than censure him for a violation
of those general rules of art, by which it is supposed necessary, on
such occasions, to relieve the eye from a scene of perplexity and
confusion.
The heads of many of our ships of war have undoubtedly great beauty and
propriety; and candour must acknowledge that some of the most elegant
and judicious have been borrowed from the French designs, which are
never left to the invention of illiterate mechanics. A multitude of
ornaments appears rather unnecessary in any building calculated for the
purposes of war. If there be any general rule to determine the subjects,
and the quantity of sculpture employed in ship-building, it seems to be
connected with the ideas of dignity and simplicity. These too are the
genuine characteristics of the Grecian and Roman orders of architecture,
as opposed to that perplexity, and rage for embellishment, which
peculiarly distinguish the Gothic. It is hardly possible for us to
recollect the various disasters to which a single hero, or goddess, on
the head of a ship, is exposed by tempestuous weather, battle, and the
unexpected encounter of ships, without trembling for the havoc and
indecency that may happen in an assemblage of gods and conc-shells,
princesses and satyrs; heroes, blunder-buffes, sea-monsters, little
children, globes and thunder-bolts, and all the apparatus necessary to
constitute the head of a ship of the first class in our navy.
In plate IV. we have sketched four heads, which are calculated for
vessels of different sizes and constructions. Fig. 6. exhibits an image
of Hercules brandishing his club over the heads of Cerberus, calculated
for a ship of the line. Fig. 7. represents Jupiter riding on his eagle,
and armed with his thunders, being a suitable head for a capital ship.
The eagle displayed by fig. 8. may serve for a frigate; and fig. 9.
which expresses an incumbent dragon, is very proper for any small vessel
with a projecting beak or prow. These figures have been selected from
many others, because, being very rarely used to decorate the head of a
ship, it is possible that several of our readers may never before have
observed them. The two first, which are usually called image-heads, are
bold, warlike, and classical. The eagle in the third is certainly a
proper emblem of dignity, force, and velocity: and it is apprehended
neither the representation of the latter, nor any other figure in that
position, are to be met with amongst our shipping.
HEAD, _avant_, is also used, in a more enlarged sense, to signify the
whole front or fore part of the ship, including the bows on each side:
the head therefore opens the column of water through which the ship
passes when advancing. Hence we say, head-sails, head-sea, head-way, &c.
Thus fig. 10. plate IV. represents one side of the fore-part, or head of
a seventy-four gun ship, together with part of the bow, keel, and
gunnel. The names of the several pieces, exhibited therein, are as
follow:
A A fore part of the keel, with _a a_ the two false keels beneath it.
A C The stem.
_a a_ The cat-head.
_b b_ The supporter of the cat-head, _sous-barbe_.
_c c_ The knight-head, or bollard-timber, of which there is one on each
side, to secure the inner-end of the bowsprit.
_d d_ The hause-holes.
_e e_ The navel-hoods, _i. e._ thick pieces of plank laid upon the bow
to strengthen the edges of the hause-holes.
_f_ The davit-chock, by which the _davit_ is firmly wedged while
employed to fish the anchor.
_g_ The bulk-head, which terminates the forecastle on the fore-side,
being called the beak-head bulk-head by ship-wrights.
H The gun-ports of the lower deck.
_h_ The gun-ports of the upper deck and forecastle.
I, I, The channels, with their dead-eyes and chain-plates.
_i_ The gripe, or fore-foot, which unites the keel with the stem,
forming a part of either.
_k k_ These dotted lines represent the thickness and descent of the
different decks from the fore-part of the ship towards the middle. The
lowest of the three dotted lines _l_ expresses the convexity of the
beams, the difference between the height of the deck in the middle of
its breadth, and at the ship’s side. This is also exhibited more clearly
in the midship-frame, where the real curve of the beam is delineated.
N. B. These lines must be always parallel to the lines which terminate
the gun-ports above and below.
_m m_ The timbers of the head part of the bowsprit.
X The rails of the head which lie across the timbers.
Q Z Fore-part of the main-wale.
R X Fore-part of the channel-wale.
U C The load water-line.
See also the continuation of a ship throughout her whole length, upon a
smaller scale, plate I. ELEVATION.
Fig. 11. represents a head-view of a ship, with the projection of her
principal timbers, and all her planks laid on one side. This figure
corresponds to that of the elevation, plate I. and the stern-view, fig.
2. plate X.
It is evident that the fore-part of a ship is called its head, from the
affinity of motion and position it bears to a fish, and in general to
the horizontal situation of all animals whilst swimming.
_By the_ HEAD, the state of a ship, which is laden deeper at the
fore-end than the after-end.
HEAD-FAST, _amarre d’avant_, a rope employed to fasten a ship to a
wharf, chain, or buoy, or to some other vessel along-side.
HEAD-LAND, _acrotere_, a name frequently given to a cape, or promontory.
HEADMOST, the situation of any ship or ships which are the most advanced
in a fleet, or line of battle.
HEAD-ROPE, that part of the bolt-rope which terminates any of the
principal sails on the upper-edge, which is accordingly sewed thereto.
See the article BOLT-ROPE.
HEAD-SAILS, _voiles de l’avant_, a general name for all those sails
which are extended on the fore-mast and bowsprit, and employed to
command the fore-part of the ship: such are the fore-sail,
fore-top-sail, fore-top-gallant-sail, jib, fore-stay-sail, and the
sprit-sail with its top-sail. This term is used in opposition to
_after-sails_, which see.
HEAD-TO-WIND, _de bout au vent_, the situation of a ship or boat, when
her head is turned to windward.
HEAD-WAY, _sillage_, the motion of advancing at sea. It is generally
used when a ship first begins to advance; or in calm weather, when it is
doubtful whether she is in a state of rest or motion. It is in both
senses opposed to retreating, or moving with the stern foremost. See the
article STERN-WAY.
HEART, _moque_, a peculiar sort of dead-eye, somewhat resembling the
shape of a heart, but differing from the common dead-eyes, inasmuch as
it is only furnished with one large hole in the middle, fig. 32. plate
II. whereas the common dead-eyes have always three holes. The hearts are
principally used to contain the _laniards_, by which the stays are
extended. See DEAD-EYE.
HEAVER, a name given by seamen to a wooden staff, employed by them as a
lever on many occasions; particularly in setting up the
top-mast-shrouds, frapping the top masts, dropping the larger blocks,
seizing the standing rigging, &c. See those articles.
HEAVING, _virer_, (_heafian_, Sax.) the act of turning about a
_capstern_, _windlass_, or other machine of the like kind, by means of
bars or handspecs.
HEAVING _the lead_. See the article SOUNDING.
HEAVING _a-head_, is advancing the ship by heaving-in the cable, or
other rope, which is fastened to an anchor at some distance before her.
To heave a-stern is therefore to draw the ship backwards by the same
operation.
HEAVING-_down_. See the article CAREENING.
HEAVING-_out_, the act of unfurling and throwing loose a sail from the
place where it had been rolled and fastened. This phrase is more
particularly applied to the stay-sails: thus we say, “Loose the
top-sails, and heave out the stay-sails!” which is accordingly done,
either to _set_ or _dry_ them.
HEAVING-_short_, is the drawing so much of the cable into the ship, by
means of the capstern or windlass, as that by advancing, she will be
almost perpendicularly above the anchor, and in a proper situation to
set sail.
HEAVING-_taught_, the act of heaving about the capstern, till the rope
applied thereto becomes streight and ready for action.
HEEL, _talon_, a name usually given to the after-end of a ship’s keel;
as also to the lower end of the stern-post, to which it is firmly
connected.
HEEL _of a mast_, the lower end, which is diminished into the frustrum
of a pyramid, so as to sink immoveably into a hole of the same shape,
cut in the step, which is attached to the ship’s keel.
HEEL _of a top-mast_, the lower end, which is sustained upon the
_tressel-trees_ by means of an iron bar, called the fid. See the article
MAST.
_To_ HEEL, _carguer_, to stoop or incline to either side. It is usually
applied to a ship when she is forced into this position by the wind
acting upon her sails, while braced obliquely across her; or by being
ballasted so as to lean more to one side than the other. See the
articles CRANK, STIFF, and TRIM.
HELM, _gouvernail_, (_helme_, Sax.) a long and flat piece of timber, or
an assemblage of several pieces, suspended along the hind part of a
ship’s stern-post, where it turns upon hinges to the right or left,
serving to direct the course of the vessel, as the tail of a fish guides
the body.
The helm is usually composed of three parts, viz. the rudder, the
tiller, and the wheel, except in small vessels, where the wheel is
unnecessary.
The length and breadth of the rudder are represented in plate VIII.
where it is evident that it becomes gradually broader in proportion to
its distance from the top, or to its depth under the water. The _back_,
or inner part of it, which joins to the stern-post, is diminished into
the form of a wedge throughout its whole length, so as that the rudder
may be more easily turned from one side to the other, where it makes an
obtuse angle with the keel. The hinges upon which it is supported are
also expressed in this figure. Those which are bolted round the
stern-post to the after extremity of the ship, are called googings, and
are furnished with a large hole on the afterpart of the stern-post. The
other parts of the hinges, which are bolted to the back of the rudder,
are called pintles, being strong cylindrical pins, which enter into the
googings, and rest upon them. The length and thickness of the rudder is
nearly equal to that of the stern-post, as represented in fig. 1. plate
X.
The rudder is turned upon its hinges by means of a long bar of timber,
called the tiller, which is fixed horizontally in its upper end within
the vessel. The movements of the tiller to the right and left,
accordingly, direct the efforts of the rudder to the government of the
ship’s course as she advances, which, in the sea-language, is called
steering. The operations of the tiller are guided and assisted by a sort
of tackle, communicating with the ship’s side, called the tiller-rope,
which is usually composed of untarred rope-yarns, for the purpose of
traversing more readily through the blocks or pullies.
In order to facilitate the management of the helm, the tiller-rope, in
all large vessels, is wound about a wheel, which acts upon it with the
powers of a crane or windlass. The rope employed in this service being
conveyed from the fore-end of the tiller _k_, to a single block _i_, on
each side of the ship, (plate III. DECK) is farther communicated to the
wheel, by means of two blocks, suspended near the mizen-mast, and two
holes immediately above, leading up to the wheel, which is fixed upon an
axis, on the quarter-deck, almost perpendicularly over the fore end of
the tiller. Five turns of the tiller-rope are usually wound about the
barrel of the wheel, and, when the helm is amidship, the middle turn is
nailed to the top of the barrel, with a mark by which the helmsman
readily discovers the situation of the helm, as the wheel turns it from
the starboard to the larboard side. The spokes of the wheel generally
reach about eight inches beyond the rim or circumference, serving as
handles to the person who steers the vessel. As the effect of a lever
increases in proportion to the length of its arm, it is evident that the
power of the helmsman, to turn the wheel, will be increased according to
the length of the spokes, beyond the circumference of the barrel.
When the helm, instead of lying in a right line with the keel, is turned
to one side or the other, as in BD, fig. 1. plate V. it receives an
immediate shock from the water, which glides along the ship’s bottom in
running _aft_ from A to B; and this fluid pushes it towards the opposite
side, whilst it is retained in this position: so that the stern, to
which the rudder is confined, receives the same impression, and
accordingly turns from B to _b_ about some point _c_ whilst the head of
the ship passes from A to _a_. It must be observed, that the current of
water falls upon the rudder obliquely, and only strikes it with that
part of its motion which acts according to the sine of incidence,
pushing it in the direction N P, with a force which not only depends on
the velocity of the ship’s course, by which this current of water is
produced, but also upon the extent of the sine of incidence. This force
is by consequence composed of the square of the velocity with which the
ship advances, and the square of the sine of incidence, which will
necessarily be greater or smaller according to circumstances; so that if
the vessel runs three or four times more swiftly, the absolute shock of
the water upon the rudder will be nine or sixteen times stronger under
the same incidence: and, if the incidence is increased, it will yet be
augmented in a greater proportion, because the square of the sine of
incidence is more enlarged. This impression, or, what is the same thing,
the power of the helm, is always very feeble, when compared with the
weight of the vessel; but as it operates with the force of a long lever,
its efforts to turn the ship are extremely advantageous. For the helm
being applied to a great distance from the centre of gravity, G, or from
the point about which the vessel turns horizontally, if the direction P
N of the impression of the water upon the rudder be prolonged, it is
evident that it will pass perpendicularly to R, widely distant from the
centre of gravity G: thus the absolute effort of the water is very
powerful. It is not therefore surprizing that this machine impresses the
ship with a considerable circular movement, by pushing the stern from B
to _b_, and the head from A to _a_; and even much farther, whilst the
sails with rapidity: because the effect of the helm always keeps pace
with the velocity with which the vessel advances[31].
Amongst the several angles that the rudder makes with the keel, there is
always one position more favourable than any of the others, as it more
readily produces the desired effect of turning the ship, in order to
change her course. To ascertain this, it must be considered, that if the
obliquity of the rudder with the keel is greater than the obtuse angle A
B D, so as to diminish that angle, the action of the water upon the
rudder will increase, and at the same time oppose the course of the ship
in a greater degree; because the angle of incidence will be more open,
so as to present a greater surface to the shock of the water, by
opposing its passage more perpendicularly. But at that time the
direction N P of the effort of the helm upon the ship will pass, with a
smaller distance from the centre of gravity G towards R, and less
approach the perpendicular N L, according to which it is absolutely
necessary that the power applied should act with a greater effect to
turn the vessel. Thus it is evident that if the obtuse angle A B D is
too much enclosed, the greatest impulse of the water will not
counterbalance the loss sustained by the distance of the direction N P
from N L; or by the great obliquity, which is given to the same
direction N P of the absolute effort of the helm with the keel A B. If,
on the contrary, the angle A B D is too much opened, the direction N P
of the force of action of the helm will become more advantageous to turn
the vessel, because it will approach nearer the perpendicular N L; so
that the line prolonged from N P will increase the line G R, by removing
R to a greater distance from the centre of gravity G: but then the helm
will receive the impression of the water too obliquely, for the angle of
incidence will be more acute; so that it will only present a small
portion of its breadth to the shock of the water, and by consequence
will only receive a feeble effort. By this principle it is easy to
conceive, that the greatest distance G R from the centre of gravity G is
not sufficient to repair the diminution of force occasioned by the too
great obliquity of the shock of the water. Hence we may conclude, that
when the water either strikes the helm too directly, or too obliquely,
it loses a great deal of the effect it ought to produce. Between the two
extremes there is therefore a mean position, which is the most
favourable to its operations.
The diagonal N P of the rectangle I L represents the absolute direction
of the effort of the water upon the helm. N I expresses the portion of
this effort which is opposed to the ship’s head-way, or which pushes her
astern, in a direction parallel to the keel. It is easily perceived that
this part N I of the whole power of the helm contributes but little to
turn the vessel; for if I N is prolonged, it appears that its direction
approaches to a very small distance G V from the centre of gravity G,
and that the arm of the lever B N=G V, to which the force is applied, is
not in the whole more than equal to half the breadth of the rudder: but
the relative force N L, which acts perpendicular to the keel, is
extremely different. If the first N I is almost useless, and even
pernicious, by retarding the velocity; the second N L is capable of a
very great effect, because it operates at a considerable distance from
the centre of gravity G of the ship, and acts upon the arm of a lever G
E, which is very long. Thus it appears, that between the effects N L and
N I, which result from the absolute effort N P, there is one which
always opposes the ship’s course, and contributes little to her motion
of turning; whilst the other produces only this movement of rotation,
without operating to retard her velocity[32].
Geometricians have determined the most advantageous angle made by the
helm with the line prolonged from the keel, and fixed it at 54° 44´
presuming that the ship is as narrow at her floating-line, or at the
line described by the surface of the water round her bottom, as at the
keel. But as this supposition is absolutely false, inasmuch as all
vessels augment their breadth from the keel upward to the extreme
breadth, where the floating-line or the highest water-line is
terminated; it follows that this angle is too large by a certain number
of degrees. For the rudder is impressed by the water, at the height of
the floating-line, more directly than at the keel, because the fluid
exactly follows the horizontal outlines of the bottom; so that a
particular position of the helm might be supposed necessary for each
different incidence which it encounters from the keel upwards. But as a
middle position may be taken between all these points, it will be
sufficient to consider the angle formed by the sides of the ship, and
her _axis_, or the middle-line of her length, at the surface of the
water, in order to determine afterwards the mean point, and the mean
angle of incidence.
It is evident that the angle 54° 44´ is too open, and very unfavourable
to the ship’s head-way, because the water acts upon the rudder there
with too great a sine of incidence, as being equal to that of the angle
which it makes with the line prolonged from the keel below: but above,
the shock of the water is almost perpendicular to the rudder, because of
the breadth of the bottom, as we have already remarked. If then the
rudder is only opposed to the fluid, by making an angle of 45° with the
line prolonged from the keel, the impression, by becoming weaker, will
be less opposed to the ship’s head-way, and the direction N P, fig. 1.
plate V. of the absolute effort of the water upon the helm drawing
nearer to the lateral perpendicular, will be placed more advantageously,
for the reasons above mentioned[33]. On the other hand, experience daily
testifies, that a ship steers well when the rudder makes the angle D B E
equal to 35° only.