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is closed upon its roller, but the only arrangement in general
vogue requires a number of short pieces of rope called " reefing
points " attached to the sail, by which it can be secured to the
yard along a line some distance from its lower edge, thus
reducing its depth by that amount.

Rigging. Rigging is divided into two classes the standing,
by which the masts are supported and stayed, and the running,
by which the yards and sails are moved and adjusted. In the
early sailing ships there was no standing rigging, the masts-
being unstayed just as with our own small sailing boats ; the
running rigging was usually of hide or gut. Ropes of twisted
vegetable fibre were subsequently introduced, while as the masts
were increased in height standing rigging was added to
support them, and some of it was converted into rope ladders
to assist the crew in reaching the upper sails and tops.

The modern improvements in rigging consist chiefly in the
extensive substitution of flexible wire rope and metal rods in
place of hemp rope, and in the use of screws for tightening the
shrouds instead of the earlier block purchase. The use of
winches and other mechanical appliances, often driven by steam
or other motive power, has tended to reduce the number of
hands formerly necessary for safely working a ship.



170

573. Portfolio of rigging and sail plans of warships, 18tli
century. (Scale 1 : 72.) Received 1908. N. 2473.

This portfolio contains rigging and sail plans for (a) 1st rate, (&) 2nd rate,
{c) 3rd rate British warships. The names of the ships are not given, but
internal evidence shows that they belonged to the period 1705-20.

Details are shown of the masts and spars, the standing and running
rigging, the principal sails including the lateen and sprit sail and the
method of working them. A sheer plan and a body plan (see No. 589) of each
vessel are also shown.

The portfolio is open to show the 2nd rate.

574. Rigging model of H.M.S. " Ganges." (Scale 1 : 24.)
Presented by Capt. H. T. Burgoyne, R.N., 1865. N. 1045.

This was rigged by Capt. Burgoyne, and shows the masts, rigging, and
sails of a wooden, two-decked line-of-battle ship of 84 guns. The names of
the sails and of the spars are indicated by labels attached to them. The
" Ganges " was built at Bombay in 1819-21 from the designs of Sir Robert
Seppings. She was last commissioned September 4th, 1857, and paid off
May 15th, 1861, being the last sailing line-of-battle ship in H.M. Navy.

Tonnage, 2,285 tons ; length, 196 5 ft. ; breadth, 52 2 ft.

575. Model of built mast, (Scale 1:24.) Presented by the
Rev. J. Hardie, 1866. N. 1137.

Lower masts were invariably built up from several timbers, owing to the
difficulty experienced in finding a single tree of the necessary size and
soundness. The practice reached its highest perfection in the first quarter
of the 19th century.

The model shows a design by Mr. B. Blake in which 38 pieces of timber,
are introduced, in addition to the cheeks for the trestle-trees.

576. Models of built masts. (Scale 1 : 48.) Presented by
J. Scott Tucker, Esq., 1865. N. 1058.

These three methods of building up a mast, for a line-of-battle ship were
devised by Mr. Joseph Tucker, surveyor to H.M. Navy, 1813-31. The
inasts are each in eight or nine pieces, breaking joint and connected by
various forms of scarfing and dowelling. The several members are
distinctively coloured.

577. Model of mainmast of H.M.S. "Nelson." (Scale 1 ; 32.)
Lent by James Young, Esq., 1876. N. 1422.

This shows, in considerable detail, a built-up mainmast for a battleship..
Seven trees were used in its construction, their timbers being dowelled
together and hooped with iron bands driven on at intervals of about 3 3 ft. ;
in earlier days servings of rope were used in place of such hoops.

The cross-trees rest on trestle-trees, supported by cheeks secured to the
mast. The leading particulars are : Overall length, 127 "2 ft. ; greatest
diameter, 41 in. ; least diameter, 30-375 in.; total weight, 26 '048 tons;
total cost, 993?.

578. Model of Blake's fid for masts and bowsprits. (Scale 1 : 12.)
Presented by the Rev. J. Hardie, 1866. N. 1100-1.

These three models show an improved fid for portable spars patented
by Mr. R. F. S. Blake in 1833. The ordinary fid is an iron cotter passing
through the heel of the mast and resting on the trestle-trees ; to " strike "
the topmast its stays must first be slacked, to allow the mast to be slightly
raised before the fid can be removed. Blake's fid obviates this lifting ;
it is pivoted on a central pin so as to readily house itself within a mortise
cut in the heel of the spar ; when in position the fid bears upon two metal



171

plates one of which may be easily removed and thus permit the free
movement of the upper spar or bowsprit.

This invention was first tried on the bowsprit of H.M. revenue cutter
*' Badger," and was subsequently extensively adopted in the Royal Navy.

579. Model of cast iron steps for masts. (Scale 1 : 12.)
Presented by the Rev. J. Hardie, 1866. N. 1105.

The squared heel of the mast fits into a shoe casting which is secured
to the keelson; this arrangement takes the place of the heavy wood
framing.

580. Model of Turnbull's topmast. (Scale 1 : 12.) Presented
by Messrs. Laurence Hill & Co, 1865. N. 1086.

This shows an arrangement of masts patented in 1864 by Capt. James
Tumbull.

The lower mast is of iron, and has a portion of the plating on the after
side of its head omitted, so as to receive the heel of the topmast, which is
afterwards locked in place by being lowered slightly. The mast cap is either
hinged or made of the elongated form shown, to permit the topmast
entering in an inclined position ; a short wooden block is used as a securing
wedge.

581. Model of, self-reefing top-sail. (Scale 1 : 12.) Lent by
H. D. P. Cunningham, Esq., R.N., 1866. N. 1095.

This method of reefing topsails and top -gallant sails was patented . by
Mr. Cunningham in 1850. It consists in arrangements by which the sail is
automatically wound round its upper yard as this yard is lowered.

In the middle of the yard is a sprocket pulley, round which passes the
bight of the halyards, which are of chain ; the fixed end of the halyard is
secured to the mast, so that the yard, as it is lowered, revolves, and thus
winds in the canvas. To provide room for the wheel and halyards, the
centre of the sail has an opening in it about the width of a " cloth," and
extending from the head to the close reef : the edges of this opening are
" roped" similarly to the edges of the sail, and connected by metal stretchers
suitably protected. The sail is also fitted with battens, increasing in depth
towards their ends so as to insure uniform rolling.

With this arrangement it is unnecessary for men to be sent aloft, except
when close reefing is required. The introduction of double topsail yards
has, however, greatly reduced the difficulty in working such sails by the
ordinary means.

582. Rigged models with flat surface sails. (Scale 1 : 48.)
Lent by Lieut. W. Congalton, R.N.R., 1865. N. 1062-3.

The sails are fitted at intervals with horizontal rods extending the full
width, and each attached to the mast by a sliding ring, an arrangement
similar to that used by the Chinese.

Examples of these sails shown are fitted to :

(a) A ship-rigged merchant sailing vessel of five masts and 1,300 tons

displacement.

(b) A large schooner-rigged screw steamship.

583. Model of proposed deadeyes. (Scale 1 : 16.) Presented
by the Rev. J. Hardie, 1866. N. 1109.

This arrangement was introduced by Mr. R. Blake to reduce the obstruc-
tion offered by the usual lanyards to the quarter-deck gun fire. The lower
deadeyes, instead of being attached directly to the channels, have long rods
interposed, so raising them above the gun level.



172

584. Model of shroud attachment. (Scale 1 : 16.) Presented
by the Rev. J. Hardie, 1866. N. 1108.

This shows a plan proposed by Mr. R. Blake for securing shrouds to
masts without a lower deadeye. In place of the latter there is a notched
rail, fixed to the channels, round which the rope rove through the deadeye
is taken.

585. Model of tightening gear for stays. (Scale 1 : 8.) Pre-
sented by the Rev. J. Hardie, 1866. N. 1138 and 1157.

In this arrangement by Mr. R. Blake the temporary tail of the stay is
provided with ratchet teeth into which a shackle, acting as a pawl, engages.
The tightening is performed by a lever which uses these teeth as its
fulcrum, and when completed the deadeye lanyard is secured.

586. Slip hooks. Presented by the Rev. J. Hardie, 1866.

N. 1102, 1111, and 1145.

These are six examples of slip-hooks, used largely for securing the
working gear of sails. The hinged portion of each hook is held either by a
shackle or by a forelock which may be respectively thrown back or with-
drawn, by means of a lanyard, to give instant release ; in one case a spring
is fitted to prevent accidental tripping.

587. Model of steel mast construction and fittings. (Scale 1 : 4.)
Made by the Admiralty, 1887. N. 1778.

This shows the upper portion of a steel lower mast. A strong plate-
forging riveted to the sides of the mast forms the " mast-cap," in which the
lower end of the topmast is supported. The various cleats, eye-plates, fair-
leads, etc., shown in position, are for the attachment of mast stays and other
rigging ; the mast plating in this vicinity is usually doubled to ensure
efficient connections.

A mast of large girth is made up of three plates of equal width and
curvature ; the edges and butts of these are flush-jointed, the former being
secured and stiffened by vertical T-bars and cross stays, as shown by
sectional view, and the latter carefully "shifted" so as to avoid lines of
lateral weakness.

These steel masts are largely utilised as ventilators ; the circular cover
shown, supported on light brackets over the open end of the hollow mast,
prevents the entrance of water while permitting the free passage of air.

588. Sail reefing gear. Lent by Roger Turner, Esq., 1896.

N. 2101.

This arrangement, patented by Mr. Turner in 1896, is intended for use
in any rig in which a spanker is used.

The reefing is performed by winding the sail on the boom, which is
necessarily of the same diameter throughout. The boom is rotated by a
ratchet gear close to the mast, and is carried on a spindle at the end, while
the outer end terminates in a spike carrying the plate attached to the topping-
lift. The fittings shown are of the size used for an 8 -ton yacht, the sail of
which, it is stated, can be reefed in 15 sees.

Framed illustrations and instruction sheets accompany the object.



SHIP DESIGN.

Among the earlier shipbuilders great skill and considerable
forethought were devoted to the design and construction of the
upper portion of the vessel, while the underwater form simply



173

followed practical traditions of very uncertain value. No sys-
tematic preliminary planning or arranging of a ship to be
constructed appears to have been undertaken till about the
17th century, for Pepys, in 1666, states that Sir Anthony Deane
was " the first that hath come to any certainty beforehand of
foretelling the draught of water of a ship before she is launched."
Early in the 16th century the "top-hamper" was reduced, and
during the three following centuries there was no marked
change in general design or appearance. A great obstacle to
progress was created in 1719 by the English Navy Board, who,
satisfied with the performances of existing types of vessels, laid
down a fixed scale of dimensions and tonnage for ships of each
class, thus leaving no power with the designers of adapting the
vessel's displacement to the increasing weight of armament and
other changes. This remained in force for nearly a century,
until the demonstrated superiority of French vessels of equal
rating initiated a greatly improved scale of dimensions. The
restrictions of each class to a fixed tonnage, however, still
survived till 1831, when Sir W. Symonds became Surveyor of
the Navy ; he then secured the adoption of designs suited to
the special requirements of the period.

Measurement. For the purpose of estimating the com-
parative bulk of vessels, or of their relative carrying capacity
for the adjustment of shipping dues, tonnage measurements
are usually given, those in present use being known as
displacement, gross or net register tonnage.

Displacement tonnage is the total weight of a ship and its
equipment in actual tons when floating at any given draught.
It is usually calculated for a ship at the " light " and " load "
water-lines respectively, and is equivalent to the weight of the
volume of water displaced by the hull. Deadweight tonnage is
the difference between the displacements at these two extreme
draughts.

Gross tonnage is a measure of the total internal capacity of
a vessel both below and above the tonnage deck, on the basis of
100 cubic feet of space to a " register ton." The cargo capacity
of a vessel is, however, alone subjected to dues, so certain
deductions from the gross tonnage are permitted for space
occupied by the engine, boiler, crew, etc., the remaining or
available space for merchandise, passengers, etc., determining
the net register tonnage.

Several rules to compute tonnage in terms of the principal
dimensions of a ship were in vogue during the 17th and 18th
centuries. The most important of these, known as " builder's
old measurement," received legal sanction in 1773, and con-
tinued in force until 1835 ; it was used officially in the Royal
Navy until 1872. As it was calculated from the length and
breadth, but took no account of depth, it led to the construction
of short deep vessels of small nominal tonnage but considerable
carrying capacity, which were, however, indifferent sea boats.



174

In 1836 the new measurement came in force making internal
capacity the basis of tonnage, and this, modified in 1854, is
now generally applied to all merchant shipping. Displacement
tonnage is, however, almost universally adopted for warships.

Form, Resistance, Stability. Within the last two centuries
much successful work has been done by mathematicians and
experimenters towards a solution of the problem of designing
a ship that should offer the least possible resistance to propulsion
and at the same time prove habitable, stable, and best fitted for
the purposes required of it.

Bouguer, in 1746, published the first investigations showing-
tile use of the "meta-centre " in determining a vessel's stability.
Bernouilli in 1757 and Euler in 1759 also published treatises
upon the laws relating to floating bodies, while in 1775 Frederick
Chapman made public the results of his long and successful
experience, and also simplified the methods of calculation by
introducing into this work the use of Simpson's rules for irregular
curves.

A Society for the Improvement of Naval Architecture was
formed in London in 1791, and this associated itself with
Col. Beaufoy's valuable experiments (1793-8) on the resistances
of various shaped bodies moving in water. The founding of
a Naval College at Portsmouth in 1806, together with the
formation of the Institute of Naval Architects (1860), and the
School of Naval Architecture at South Kensington (1864), have
done much to encourage the scientific study of ship-structure,
including the strength of materials, the strains to which vessels
are -subjected in a seaway, 'and the general questions of displace-
ment and stability.

The capsizing of H.M.S. " Captain " at sea in 1870, and
of the S.S. "Daphne" on the Clyde in 1883, emphasised the
need of careful investigations of stability under every possible
condition, and have resulted in more elaborate calculations
before launching, supplemented in all new types by experimental
verification when equipped.

The important factors accepted at present in the total
resistance of a ship are : (a) Skin resistance or friction,
depending upon the area and nature of the immersed surface ;
(6) Resistance due to eddy-making, which is usually confined
to the stern and can be indefinitely reduced by providing a fine
afterbody ; (c) Resistance due to wave-making, which is chiefly
influenced by the relationship between the form and proportion
of the vessel and the actual speed.

Skin resistance varies enormously with the roughness of the
immersed surface and increases nearly as the square of the
speed. For lengths up to 50 feet its mean value diminishes as
the length is increased, owing to the motion given to the water

* Robert Fulton, when designing his pioneer steam-boats of a few years
later, appears to have been the first to make practical use of these results.



175

by the leading portions ; in the case of a ship the skin friction
forms from 40 to 80 per cent, of the total resistance.

Eddy-making is clearly seen round a square-sterned barge ;
in ordinary ships it causes only about 8 per cent, 'of the total
resistance.

Wave-making is the serious resistance at high speeds, and
on account of the curious manner in which it fluctuates with
the speed and proportions of a vessel is still the most uncertain
quantity. Mr. Scott Russell had suggested certain relationships
between the length and speed of ships, but the experimental
model system of the late Mr. W. Froude, initiated about 1874,
has been the chief means by which this matter has been
elucidated. By hauling a model at various speeds through
still water in a suitable tank a complete series of reliable
resistances is obtained, which, when plotted, show the varying
natures of these values, and from these, by deducting the
simpler skin resistance, the wave losses are determined. In
this way Mr. Froude experimentally proved his law of " corre-
sponding speeds," which states that "at speeds of ship and
' model related to one another as the square roots of the length,,
' the wave-making resistances vary as the displacements."

The wave created by an advancing ship should travel with
the vessel and have its crest near the stern, so as to give a
forward hydrostatic pressure. When such a ship is forced
beyond its suitable speed the waves diverge from the sides-
and waste themselves in still water at a distance ; such a wave
is absorbing fresh energy in its renewal, and thus causing an
excessive resistance as compared with that at speeds when the
wave is utilised.

Although at one time most strongly opposed, Mr. Froude's
principle of experimenting has shown itself quite reliable and is
now in practical use throughout the shipbuilding world. From
the results obtained from models in such tanks it is now easy to
predict the resistance of ships of entirely new forms travelling
at unprecedented speeds.

Laying off is the operation by which, after the dimensions
and shape of a ship have been fully determined and recorded
upon drawings, the true size and shape of the various members,
of the structure are set out upon a level floor. Moulds or
templates made to these lines afford the necessary guidance
to workmen for fashioning the material and for fixing it in its
place when finished. In some small yards where the type of
vessel is uniform and the material chiefly wood, the trained eye
and judgment of an experienced foreman may dispense with
elaborate plans and lines, but with any extended or varied
class of work such preliminaries are indispensable for accuracy
and rapidity of construction. With the use of iron and steel
for shipbuilding purposes, well-prepared plans have become
imperative ; the lesser scantlings and greater hardness of the
material make alterations difficult and expensive, while most of
the old " fairing " processes have become impracticable.



176

589. Portfolio of sheer draughts of warships, 18th century.
(Scale 1 : 48.) Received 1908. N. 2472.

This portfolio contains sheer draughts of four 4th-rate British warships
(1700-1719).

The sheer draught is the first set of drawings sent to the builder;
it provides the necessary information for laying-off to full size the
principal framing, and also gives a good external representation of the
completed hull. Each sheer draught comprises : (a) A sheer plan or side
elevation showing positions of the decks, gun-ports, channels, masts, bow
and stern decorations, etc. ; (&) A stern elevation showing details of the
transom framing and the arrangement of after galleries and decorative
work ; (c) A half -breadth plan showing horizontal projections of the top
sides, the principal decks, the load water plane and of a number of equi-
distant level planes in the underwater body. Near this plan are also some
rabatted diagonals, showing the true form of a number of planes drawn
diagonally in the body plan ; they are of considerable value in the " fairing "
process and also indicate the lines of heads and heels of frame timbers ;
(d) A body plan showing transverse outlines of the hull taken at a number
of equidistant vertical stations; the curves of centres for describing the
arcs which form portions of these outlines are also drawn in.

The vessels' names, with particulars taken from the drawing, are :





Length


Breadth








Name.


on Gun
Deck,
Feet,


extreme,
Feet.


Tonnage


Guns.


Launched.


" Exeter "


147


38-5


950


60


About 1700.


" Strafford " -


130


35-0


700


52


Plymouth, 1714.


" Winchester "


130


33-5


700


52


1717.


"Deptford" -


131


35-25


700


50


Portsmouth, 1719.



The portfolio is open to show the " Winchester."



590. Portfolio of characteristic "lines" of
century. (Scale 1 : 48.) Received 1908.



warships, 18th
N. 2471.



During the first half of the 18th century several attempts were made to
standardize the design of the various classes of warships. This portfolio,
which was possibly intended for comparison in this respect, contains,
superposed, characteristic curves of the 60- gun ships enumerated below,
and shows the great diversity of form given to vessels of this class by the
master shipwrights of different Royal dockyards. The curves drawn to
ordinates from a common base line, represent : (a) Outlines of the trans-
verse midship sections ; (&) Horizontal projections of the topsides and
principal decks ; (c) Horizontal projections of the load water-plane and of
several under- water planes ; (d) E/abatted diagonals, which show the true
lines of intersection with the hull of a number of diagonal planes (see
No. 589).

The portfolio is open to show the lines of the " Dragon " (1733),
"Rippon" (1730), "Tilbury" (1730), " Weymouth" (1733) and " Superbe,"
the latter, a 56-gun ship captured from the French in 1710, shows generally a
finer entrance and run as well as sharper midship floors than the British
ships.

The vessels shown on the remaining two sheets are : "Augusta" (1733),
"Canterbury" (1741), "Jersey" (1733), "Kingston" (1736), "Princess
Mary" (1737), "Rupert" (1736), "Strafford" (1733), "Worcester" (1733),
and " unnamed " (1742).



177

591. "Laying-off " models. (Scale 1 : 48.) Received 1874.

N. 1396.

These half-block models of the fore and after extremities of a wood-built
sailing vessel show the principal lines used in the " laying-off " process.

For the purpose of laying-off, i.e., representing details of a vessel's true

form upon paper or the scrive-board, the hull is supposed to be cut by three

sets of planes parallel to the (a) transverse vertical, (b) longitudinal vertical,

c) horizontal planes, respectively ; lines of intersection of these planes with

the outside surface of the ship are shown upon the models.

The projections of these sections are known as (a) square stations,
(b) bow and buttock lines, (c) level lines, (a) Appear straight in the sheer
and half -breadth plans, and curved in the body plan; (b) appear straight
in the body and half- breadth and curved in sheer ; (c) appear straight in
body and sheer and curved in half-breadth plan. When (c) are parallel to
the load water plane of the ship they are termed " water-lines."

Besides the lines mentioned, there are others shown which are used in
the operations of fairing, framing, and planking the vessel ; such are the
" diagonal " and " bearding " lines, also the joints of canted frames at the
bow and stern and the rebates of keel, stem, and deadwood.

The " laying-off " process for the midship portions are similar in
principle to the above, but are simpler in detail.

592. Whole model of schooner, with, flat bottom. (Scale
1 : 36.) Presented by J. Scott Tucker, Esq., 1865.

N. 1056.

This represents a design, prepared about 1820, by Mr. J. Tucker for an



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