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(a) shows a deep outer frame-bar with a smaller reversed angle riveted to
its inner edge.

The ends of the deck beams shown have been deepened to strengthen
the joint by splitting and opening them, then inserting an additional piece
in the web and welding it into position. Usually the inserted web com-
pletely fills the space and forms a solid end, but frequently the lightened
arrangement shown, in which a hole is left in the web, is adopted. The
connection between a frame and a beam is sometimes made by a bracket
plate riveted to the two, thus saving the expensive smith- work.

685. Models of deck stringers. (Scale 1:4.) Made by the
Admiralty, 1827. N. 1738-9.

These illustrate alternative methods of fitting a deck stringer plate to
a steel-built vessel, when such plate forms a portion of a watertight or
non-watertight deck respectively. In both cases the stringer plate is
scored over the ship's frames, here shown of the Z-section, and is secured
to the inside flanges of the same by means of a continuous longitudinal
angle- bar.

Under ordinary circumstances the inner edge of a deck stringer-plate
is connected to the shell plating by short angle-bars fitted between the
frames as shown by model (a). When, however, a watertight boundary
is required, a complete frame of angle-bar, carefully riveted and caulked,
is fitted as shown in (fe). .

686. Model showing bulkhead construction. (Scale 1:4.)
Made by the Admiralty, 1887. N. 1753.

This represents a portion of a watertight bulkhead jointed with flush
edges and butts.

The plating is stiffened on one side by vertical angle-bars, and on the
other by horizontal T-bars which also serve as cover strips for the butt
joints. The distribution of the joints and the details of the riveting are
also shown. The main bulkheads of modern warships in H.M. Navy have
been further stiffened by the addition of vertical Z or H-bars, provided with
plate brackets to their heads, heels, and sides.

687. Model of attachment of watertight bulkheads. (Scale
1 : 4.) Made by the Admiralty, 1887. N. 1754.

This shows the method of securing the lower part of a transverse
watertight bulkhead to the inner bottom of a vessel built on the cellular
system.

A boundary angle- bar is attached by means of closely- spaced rivets to
the inner-bottom plating and to the lower edge of the bulkhead plates,
a wide liner being fitted over the sunken strokes so as to level up the
surface and also to compensate for the loss of transverse strength at this
section (see No. 688). The abutments of a fore-and-aft coal-bunker or wing
bulkhead are shown, also the vertical stiffeners to the transverse bulkhead,
together with portions of the cellular framing below. It is now usual to fit
small bracket plates to the heels of all vertical stiffeners, and also to place
if possible solid -plate frames directly under all watertight bulkheads.



207

688. Model of attachment of watertight bulkheads. (Scale
1 : 4.) Made by the Admiralty, 1887. N. 1755.

Tliis shows a method of securing a transverse watertight bulkhead to
the ship's plating.

A continuous boundary angle-bar, well riveted and caulked on the
bulkhead, is similarly connected to the shell- plating. Where there are
sunken strakes of plating a wide liner is fitted, in order to simplify the
work and to strengthen a section that is considerably weakened by the
number of holes necessary for watertight riveting. Gusset or bracket
plates are fitted between the bulkhead and the adjoining frames on each
side ; these stiffen the shell and help to resist the racking stresses to which
the plating and framing are subjected in a sea-way.

689. Models of watertight bulkhead joints. (Scale 1 : 4.)
Made by the Admiralty, 1887. N. 1756-8.

For the maintenance of structural strength in a steel-built vessel it is
often necessary to continue beams and girders completely through the
watertight bulkheads. To insure watertightness at such intersections, short
connecting angle-bars, fashioned to a template and carefully riveted and
caulked, are generally fitted around the joints.

The accompanying models show details of the arrangements when the
bulkhead is pierced respectively by a bulb angle-bar, a bulb T-bar, and a
box- girder.

690. Models of bulwarks. (Scale 1 : 4.) Made by the
Admiralty, 1887. N. 1740-2.

These three models illustrate various modes of forming the side structure
above the upper deck in steel or composite-built vessels.

(a) is a combination of wood and metal ; a rough- tree stanchion carries
the outside wooden planking and top rail, and is secured at the heel to the
sheer strake and to an inner " clamp plate/' It also shows the usual method
of working a wooden " waterway " with the adjoining deck planking.

In (b) and (c) the topsides are formed entirely of steel, and are stiffened,
in one case by means of a bulwark stay so riveted to the deck, top rail, and
side plating as to afford a distributed support ; in the other by a continuation
of the transverse frames of the ship to the height of the top rail.

Freeing ports are fitted to the bulwark plating of all vessels, sufficient
in number to discharge readily any water accumulating upon the upper deck ;
as their doors only open outwards they act as valves in preventing water
from entering. Details of bulwark framing and plating for composite
vessels are shown on diagrams No. 643.

691. Model of deck planking. (Scale 1 : 4.) Made by the
Admiralty, 1887. N. 1760-1.

These models show the usual method of securing a wooden deck to iron
or steel beams when no deck plating is fitted.

For deck planks over 8 in. in width, Lloyd's rules require two bolt
fastenings in each beam, secured by nuts 011 the underside of the flange.
The butts of deck plank are, if possible, supported on a beam ; where the
beam flanges are not of sufficient width to receive the necessary fastenings
a short piece of plate is riveted to the beam, and the ends of plank secured
to it as shown.

692. Model of deck plating and planking. (Scale 1 : 12.)
Made by the Admiralty, 1887. N. 1759.

This is a portion of an iron or steel deck of single thickness, with an
upper covering of wooden planking. The positions of the deck beams and
of the butt straps and edge strips to the plating can be seen, together with



208

full details of the riveting in each. The butts, edges, and fastenings of
wooden planking are disposed as shown ; the planking is secured by
galvanised iron bolts, which pierce the plating between the beams and are
fitted with nuts below.

693. Model of protective deck plating. (Scale 1 : 12.) Made
by the Admiralty, 1887. N. 1762-3.

This deck plating, when fitted for the purpose of protecting the vital
parts of a warship from gun fire, is usually laid in several thicknesses. The
accompanying models illustrate an arrangement for fitting and riveting
such plating when worked in two and three thicknesses respectively.

The butts and edges are generally disposed as shown, each thickness of
plating being utilised as a butt strap and edge strip to others. In this way
the cost of riveting is minimised, as three single rows of rivets are sufficient
to secure the two edges in one case, while four rows secure three edges as
shown in the other. The usual practice is to first rivet the lower thickness
to the ship's beams, then to fasten the upper thicknesses to the lower by
through or tap-rivets disposed between the beams.

In one model the butts of the upper thickness rivet to a beam ; the
more recent practice is, however, to arrange all butts clear of beams where
practicable.



694. Rudder and stern-post. Lent by Messrs. \Vm. Jessop
and Sons, 1884. N. 1670.

This is a duplicate of a crucible cast steel stem-frame and rudder, made
in 1881, which is believed to have been the first stern-post made in the way
that has now become almost universal. It weighs 2 cwt., and was designed
by Mr. J. F. Hall, for a launch built by Mr. John Shuttleworth, of Hull.
She was 25 ft. long, 5 ft. beam, 3*17 ft. deep to gunwales, and was fitted
with two-stage expansion engines indicating 3 h.p., and giving a speed of
6 to 7 knots. She carried 3 5 tons of cargo, in addition to a supply of coal.

The earlier practice was to make the stern-post as a forging by welding
up portions in iron or steel, but large steel castings in Bessemer or (Siemens
metal are now used in all classes of steamers.

695. Model of stem and stern frames of battleship. (Scale
1 : 12.) Made by the Admiralty, 1887. N. 1751-2.

These represent the forged iron posts for a battleship of the " Admiral "
class, 1882.

The details of the connections with the shell plating and with the flat
and vertical keels are shown in each case, while the particulars of the special
framing associated with this type of post are represented in ~No. 666.

With the introduction of large steel castings into ship construction a
hollowed or gulleted form of stem and stem post was rendered possible,
with horizontal ribs and ledges for the more efficient attachment to the hull
framing and plating.

696. Model of frame of balanced rudder. (Scale 1 : 24.) Made
by the Darlington Forge Co., 1895. N. 2067.

This represents the cast- steel frame of the rudders of H.M. cruisers
" Andromache " and " Apollo," built at Chatham in 1890-1.

The rudder is of the balanced type, in which the axis of turning
coincides with the centre of pressure when acting, so that but little power
is required in setting and retaining the rudder in any desired position.
This centre of pressure is at about 3 of the width of the rudder from its
leading edge.

The rudder is completed by filling the frame with light wood, and then
covering it on each side with thin steel plating, tap- riveted on ; the wood



209

packing, however, is sometimes omitted. The weight of the rudder is
carried by a collar, within the ship, resting on balls or bearing rollers. The
lower end of the rudder turns in a socket on the stern post (see No. 128).

697. Model of shaft brackets for S.S. " Empress of China."
(Scale 1 : 24.) Made by the Darlington Forge Co., 1895.

N. 2062.

This represents the shaft brackets of this twin screw steamer, built at
Barrow- in- Furness in 1891, for the Canadian Pacific Railway Co.

They are formed in a single steel casting, which has three large vertical
flanges for connecting it to the stem post and to the transverse framing of
the ship.

The actual weight of this casting was 26 tons.

698. Model of stem of H.M.S. "Royal Sovereign," 1892.
(Scale 1 : 16.) Made by the Admiralty, 1893. N. 2016.

This cast steel stem-piece is formed in two parts, connected together by
a scarf -joint as shown ; its total weight was 25 tons.

The whole is strengthened against ramming stresses by the abutments
of the various decks and the shell plating, while special support is given to
the spur or ram by its connection with the protective deck plating, which
is 2 5 in. thick, and extends backwards from the bow through a distance
of 76 ft.

699. Model of shaft bracket for H.M.S. "Royal Sovereign."
(Scale 1 : 24.) Made by the Darlington Forge Co., 1895.

N. 2066.

This represents one of a pair of cast- steel brackets for this twin screw
battleship, built at Portsmouth in 1892.

Both arms of the casting pierce the shell plating of the ship, and the
upper one is riveted to a thick " palm " plate strongly connected to the
general framing of the vessel, while the lower one is joined, by means of a
scarf, to the lower arm of the opposite bracket, and both #re riveted to a special
framing attached to the vertical keel.

700. Model of stern frame. (Scale 1 : 24.) .Made by the
Darlington Forge Co., 1895. N. 2064.

This is a combined stern and rudder-post of cast steel, as fitted to the
Peninsular and Oriental Co.'s steamships " Australia " and " Himalaya,"
built at Greenock in 1892.

The frame is in three parts, scarfed together and riveted were indicated.
It is provided with a boss for a single screw-propeller, and five gudgeons for
carrying the rudder ; there are also projecting arms for efficient connection
with the hull framing.

The total weight of the three castings was 23 tons.

701. Model of stern castings. (Scale 1 : 24.) Made by the
Darlington Forge Co., 1895. N. 2063.

This represents a cast steel stern- frame with shaft brackets attached, as
fitted to the Union Steamship Co.'s twin-screw vessels " Gaul," " Goth," and
" Greek," built at Belfast in 1893. In these steamers the screw shafts are
so close together that the propeller paths would overlap were the port screw
not somewhat in front of the starboard one (see No. 702).

The stern-post shows the arrangements for connecting it with the flat
keels and to the transverse framing of the ship.

702. Models of stern castings for S.S. " Cevic." (Scale 1 : 24.)
Made by the Darlington Forge Co., 1895. N. 2061.

These represent the cast steel stem-post, rudder-frame, and shaft-
brackets in their correct relative positions, as fitted to this twin- screw
IJ .0773.



210

White Star liner, built at Belfast in 1894. The overhanging form of
stern-post here shown permits of an increased immersion of the propellers
and a closer arrangement of the centre lines of the propeller shafting ;
the reduced area of after dead-wood also gives a shorter turning radius
to the vessel.

A single casting, riveted to the stem- post and adjoining framing of the
ship, forms a double shaft-bracket ; in its construction provision is made for
placing the port propeller in advance of the starboard one. The rudder is
completed by riveting a steel plate between the projecting arms of the
frame casting.

"Weight of stem frames, 17 tons ; weight of double shaft- bracket,
12 tons ; weight of rudder-frame, 11*5 tons.

703. Models of stem, stern and rudder castings of H.M.S.
" Majestic." (Scale 1 : 24.) Made by the Darlington Forge
Co, 1895. N. 2065.

These represent cast-steel frames as used in the construction of this
first-class battleship at Portsmouth in 1894-5.

The stem and stern-posts show the rebates for the attachment of the
flat keel plates and shell plating, and also the horizontal lugs or ledges for
the attachment of decks, platforms and breasthooks : a projecting spur or
ram with special stiffening web forms part of the stem casting. On the
upper portion of the rudder-frame are shown the two wedge-shaped stops
for limiting the angle of turning.

The actual weights of these castings were: stem, 27 - 5 tons; stern,
8 tons ; rudder, 13 tons.

704. Model of stem and stern frames of a cruiser. (Scale
1 : 24.) Made by the Darlington Forge Co., 1895.

N. 2068.

These frames were cast in steel for the Spanish cruiser " Princesa de
Asturias," 6,648 tons' displacement, built at Caraccas in 1895,

Both castings show the usual rebate for housing the shell plating, also
an exceptional length of lap for securing to th^ flat keel plates. The stem
has provision made for the ram plate and for the abutments of upper,
main, and lower decks, by which it is greatly strengthened. The stem
frame has on its fore end a long vertical web for attachment to the ship-
structure, and on its after end a rectangular recess to receive the lower
palms of the shaft-brackets.

705. Model of stern casting for double rudders. (Scale 1 : 8.)
Received 1901. N. 2261

This represents a cast-steel stern-post as fitted to H.M. ram cruisers
" Arrogant," " Furious," " Gladiator " and " Vindictive," built in 1896-1900
at the Royal Dockyards. To ensure rapid manoeuvring power, these vessels
are provided with double rudders.

The casting weighs about 10 tons, but is made in two parts connected
together at the position shown by a scarf joint and covering-plate. The
upper end is riveted to the protective deck and the lower end to the flat-
keel plates ; additional connection with the hull of the ship is obtained by the
outer, or shell, plating which is riveted into the rebate extending along the
whole length of the casting. At the side are projecting palms to which
the lower arms of the propeller- shaft brackets are riveted.

The rudder-posts pass through sockets, and the weight of each rudder is
carried upon a horizontal flange which forms part of the main casting ; a
small spur, at the heel of the main rudder-post, carries a steadying pintle.
For full details of the rudders and of the complete steering machinery
see No. 1064.



211

706. Model of stern frame for H.M.S. " Formidable " (1898).
(Scale 1 : 12.) Received 1907. N. 2440.

This represents the cast steel stern-frame as adopted for the eight
battleships of the " Formidable " class.

In order to improve the turning qualities of long, fast vessels it has
been a practice, since about 1894, in designs both for merchant and war-
ships, to cut away a portion of the after dead-wood. This necessitates
some modification of the after-framing and, in the example shown, has
originated the peculiar arched or overhanging stern-casting, having its
after-edge or rudder-post carried vertically downwards to nearly the normal
keel-line; a short intermediate portion or "heel" provides a suitable
bearing for the after-end of the vessel when in dry- dock. Vertical and
horizontal webs are cast on the frame for the attachment of internal
decks and plate frames. The weight of the actual casting was about
11 tons.

A small separate model illustrates the method of scarfing and riveting
the lower " palms " of the propeller brackets for these ships.

For details of the connections of these parts with the adjacent ship-
structure see No. 1063.

707. Models of stem, stern and rudder castings for S.S.
" Ermack." (Scale 1 : 24.) Made by the Darlington Forge
Co., 1902. N. 2289.

These represent the steel castings for the ice-breaking steamer
" Ermack." built in 1898 at Elswick, by Messrs. Sir W. Gr. Armstrong,
Whitworth & Co., for the Russian Government.

The stem-post above the water-line has the usual shape, but from a
point near the line of maximum draught of the vessel it tarns sharply
backwards and continues in a gradual downward slope for a length of about
32 ft., when it again assumes a more vertical direction till it terminates in a
boss for a screw propeller. The long overhanging bow thus obtained
causes the vessel, after impact, to rise upon an ice-field, thus utilising the
actual weight of the ship to break a passage through the ice ; this action is
further assisted by the V-shaped section of the underside of the casting,
and also by the violent disturbance given to the water below by the
bow propeller. Beyond the boss is a projecting lip or " palm " to take
the foremost keel plates which here rise considerably above the normal
keel line.

The stern-frame is a combined rudder and stem-post, the latter portion
having a boss for one of the three after propellers, and the former the
gudgeons for carrying the rudder. On each side of the screw aperture the
vertical edges of the casting have bevelled faces so as to give a ready
passage for any obstructing masses of floating ice ; near the heel of the
stern-post is an abutment and scarf for attaching the after ends of the
keel plates. The fork made by the upper part of this casting forms
the lower boundary of a large recess provided in the stern of the vessel,
for housing the bow of a ship which may require towing into an ice-
bound harbour or which may be required as an auxiliary in forcing a
channel.

Both the bow and stem-frames show the usual rebates for the attach-
ment of the shell plating, but the internal gulleting of the castings is
reduced to the minimum required for efficient riveting, so as to give
increased solidity to sections that may be subjected to exceptional stresses.
A number of transverse and longitudinal ribs or flanges provide means for
connecting the castings with the general framing of the ship.

The rudder, shown in position, is a single steel casting, and is provided
with stops to limit its angle of turning. The actual weights of the
castings were : Stem, 16 2 tons ; stem frame, 7 9 tons ; rudder, 12 7 tons.

O 2



212

708. Model of stem post of H.M.S. " Vengeance." (Scale 1 :
24.) Made by the Darlington Forge Co., 1902. N. 2288.

This represents the cast steel stem-post and rain of a first- class battleship,
built by Messrs. Tickers, Son and Maxim at Barrow-in-Fumess in
1898-1901.

Owing to the sharp angular rise given to the fore-foot of this type of
vessel, the stem casting is wholly above the level of the keel line. It is,
however, scarfed to the flat keel plates in the usual manner, the latter being
bent upwards for this purpose ; the lower edges of the vertical keelson plates
are riveted to a longitudinal web formed on the inside of the lower portion
of the casting.

The ram itself is nearer the water-line of the vessel than in earlier types
and is more completely supported. Just above the spur is a broad projecting
ledge to which the 2 -in. protective deck is riveted, and immediately below
this, in the centre of the spur, provision is made for attaching a special ram
plate 2 in. thick. In addition to these there is the support derived from the
ordinary shell plating of the ship and also from a protective skin of 2 -in.
nickel steel which covers the bow on both sides to a height of 10 ft. above
the water-line. Double rebates are shown for housing these two thicknesses
of plating, and at the upper portion of the casting are edges for attaching
the foremost ends of the main and upper decks. The actual weight of the
casting was 13 tons.

709. Models of stern and rudder frames of H.M.S. " Drake."
(Scale 1 : 24.) Made by the Darlington Forge Co., 1902.

N. 2287.

These were cast in steel for a first-class armoured cruiser built at
Pembroke in 1899-1901. (See No. 135.)

The stern-frame rises considerably above the normal keel line, the after
dead-wood being cut away in this particular class of vessel. The after keel-
plates are bent to the angle of the casting, and secured to it by a double
scarf, shown at the lower end of the model ; near this scarf are two large
projecting palms for cariying the lower arms of the screw-propeller brackets.

A rebate for housing the ends of the outer skin plating is shown along
the whole length of the stem casting ; there are various lugs or ledges for
attaching the decks and platforms of the ship. At the heel of the upright
post is a wedge-shaped stop for limiting the turning-angle of the rudder.

The rudder-frame, shown in position, is a single casting, and when
covered with thin steel plating, will form a rudder of balanced type. A
steadying pintle is fitted below the heel of the stem post, but the actual
weight of the rudder is carried upon a turntable which forms part of the
main stem casting as in the model of steering gear No. 1064.

"Weight of stem frame, 25 tons ; weight of rudder, 18' 6 tons.



710. Model of portion of main deck battery. (Scale 1 : 16.)
Presented by Messrs. R. Napier and Sons, 1867. N. 1180.

This model shows three broadside guns and their mountings, as arranged
in the warships proposed by Vice- Admiral E. P. Halsted in 1865-7. (See
Nos. 98 to 105.) The side armour extends up to the main deck with lighter
plating over the battery ; the upper work is formed with tumbling rails so
that it can be placed clear of the turret guns when required. The heaviest
gun shown has a winch training gear ; all three guns are mounted on iron
carriages and slides, designed by Capt. T. B. Heathorn, B.A., which give a
muzzle-pivoting movement ; the ports are, however, of the large size then
usual,



213

711. Model of gun turret, (Scale 1 : 16.) Presented by
Messrs. R. Napier and Sons, 1867. N. 1182.

This represents Mr. R. Napier's turret, for cariying two Whitworth
9 -in. M.L. guns, which was introduced in the designs for the combined turret
and broadside armour-plated ships-of-war proposed by Yice-Admiral
E. H. Halsted in 1865-7. (See Nos. 98 to 105.)

The turret is 25 ft. external diameter and 21 ft. internal ; the armour
consists of 8 in. of solid iron in complete rings 2 5 ft. high, then a packing
of vertical or diagonal beams of teak 8 in. thick, supported by Hughes' hollow
stringers formed into complete rings and secured to the inner iron skin,
which is 1 in. thick. The roof of the turret is formed of alternately reversed
T- irons, which form a shield that leaves ample ventilation. The turret is
supported on a live ring of coned rollers, which travel on a bed formed
around a circular main deck hatchway, with coamings 13 ft. external diam.
and 4 5 ft. high, protected by armour similar to that on the turret ; the space
between this armour and the turret affords ventilation for the main deck.



Online LibraryScience Museum (Great Britain)Catalogue of the naval and marine engineering collection in the ... museum .. → online text (page 29 of 58)