Science Museum (Great Britain).

Catalogue of the naval and marine engineering collection in the ... museum .. online

. (page 30 of 58)
Online LibraryScience Museum (Great Britain)Catalogue of the naval and marine engineering collection in the ... museum .. → online text (page 30 of 58)
Font size
QR-code for this ebook

This armoured base protects the ammunition, hoists, etc., as well as the
vertical shaft by which the turret is turned by steam power from below.

Sections of this turret are shown in several of the half models of the
Halsted ships.


712. Diagrams showing ventilation of a battleship. (Scale
1 : 48.) Made by the Admiralty, 1887. N. 1798.

These show in profile, plan and section, the general arrangements
adopted for ventilating a vessel of the central citadel type.

The spaces between main and upper decks are principally ventilated by
the hatchways and side scuttles ; those between main and protective decks
by means of vertical shafts, rising above the upper deck and fitted with
adjustable cowls, so that the motion of the ship or direction of the wind can
be utilised to force air into or withdraw air from the interior. This air is
distributed through horizontal pipes or trunks opening into the various
compartments by means of sliding shutters or louvres.

The updraught produced by heated air in the funnel casing is used to
draw the foul air from the coal-bunkers through exhaust trunks, the fresh
air being supplied by pipes fitted between the ship's frames and reaching to
the topsides. Free circulation of air to engine and boiler-rooms is secured
by the large ventilators and cowls amidships rising well above the upper
deck, from which also the supply to the steam fans is drawn when the
boilers are under forced draught.

As the openings in the protective deck are necessarily limited in
number, most of the compartments below are ventilated artificially.
Revolving fans, driven by steam or electric motors, draw fresh air from
downcast shafts and force it through large trunks, provided with numerous
branches and outlets, to every accessible part of the fore and after ends of
the ship, including magazines, capstan, steering, shell, and provision rooms,
all these compartments exhausting into a main trunk leading to the funnel-

As a ventilating pipe forms a passage through the watertight bulkheads,
a weighted valve is fitted which, by a trigger gear actuated by a float, closes
the pipe if water enters its compartment.

Supply shafts and trunks are shown in blue ; exhaust shafts and trunks
are shown in red.

Since about 1900 the above system has been considerably modified by
dividing each vessel into a number of separately-ventilated units, i.e.,
between the main watertight bulkheads. Each unit is provided with one,
or more, small motor fans (see Mechanical Engineering Collection), these


draw air from the upper deck and deliver it, through a common air-chamber,
to the local sub-divisions ; special exhaust trunks are fitted where necessary.
This arrangement obviates the piercing of watertight partitions and the use
of automatic ventilation valves.

713. Model of ship ventilator. (Scale 1 : 12.) Presented by
the Rev. J. Hardie, 1866. N. 1097.

This shows an octagonal wooden trunk, which communicates with the
deck to be ventilated, and is surmounted by a metal cowl with a conical
mouth which can be set to windward. In bad weather the cowl is removed
and the trunk closed by a wooden cover. It was designed for use in troop-
ships by Mr. R. Blake, Master Shipwright, H.M. Dockyards (1833-55).

714. Ventilators. Lent by the Can-on Co., 1890. N. 1847.

These are for ventilating deck-houses and ships' cabins.

(a) is a circular brass plate, with radial slots and guides, for attaching to
doors or bulkheads ; this plate is covered by a revolving slotted disc, by
which the ventilation can be regulated.

(&) is a more elaborate fitting for the decks above state rooms, etc. A
ventilating shaft, secured by a flange to this deck, is surmounted by an
adjustable cap to prevent the entry of rain or spray. Inside the cap is a
strip of india-rubber, so that during rough weather when screwed down upon
the bevelled rim of the ventilating tube the joint shall be watertight.

715. Model of spherical valve for ventilator. (Scale 1 : 24.)
Received 1907. N. 2445.

This arrangement for controlling openings in watertight decks was
patented by Mr. James Casey in 1895. It consists of a hollow spherical
valve, cut with a large single passage and enclosed in watertight casings ;
adjustable bearings and packing are used to ensure easy working and
watertightness and the valve is opened or closed by external handles or
levers. It was intended for use as a general substitute for the ordinary
sliding doors, hatches, scuttles, etc., and is here shown as fitted to a venti-
lating shaft on a vessel's deck ; with slight modifications it could be attached
to openings in ships' sides and bulkheads.

Some experiments were made with this device on English and French
vessels, but it has not been permanently adopted.

716. Model and diagram of Boyle's ship ventilators. (Scale
1 : 12 and 1 : 120.) Presented by Messrs. R. Boyle and Son,
1898. N. 2163.

This shows a pair of Mr, R. Boyle's patent ventilators ; the taller one is
the " down- cast " by which air, from, the above -deck level, is carried into
the depths of a ship; the shorter one has an induction apparatus, or
" air pump," by which vitiated air is removed from the vessel. The
down-cast apparatus acts somewhat like the old wind-sail, but has four
mouths, so that it does not require setting ; at the side is a trap and a
branch outlet closed by a flap, by which if spray is carried down it shall
escape sideways into an adjacent scupper. The up-take, or air-pump
ventilator, is also stationary, but has four orifices with vertical shutters and
guides which so direct the passing air as to cause it to exhaust from the
ship by an inductive action.

The model is fitted with glass tubes containing tufts of cotton- wool
which show the direction of the current when either ventilator is blown
across. An adjacent diagram shows a steamship fitted with these venti-
lators, so arranged that fresh air is supplied near the bottom of each deck
by down-cast ventilators, while the vitiated air is carried off by up-cast
ventilators drawing from the upper part of each deck.


717. Model of a hinged watertight door. (Scale 1 : 4.) Made
by the Admiralty, 1887. N. 1796.

This shows the Admiralty construction and fittings of a watertight door
011 a bulkhead above the protective deck.

The door is carried on hinges, and is provided with a slightly-raised
flange round its inner edges which when closed presses against a narrow
strip of sheet india-rubber secured in a frame attached to the bulkhead.
The ten clips or handles arranged round the door are forced over brass
wedges on the back of the door; the powerful closing pressure thus
exerted insures an efficient watertight joint.

Since 1889 the raised flange has been usually secured to the bulkhead
and the india-rubber to the door.

718. Model of watertight door. (Scale 1 : 4.) Presented by
Messrs. Mechan and Sons, Ltd., 1908. N. 2469.

This represents a modern form of hinged door largely used in the Royal
Navy and mercantile marine for closing openings in watertight bulkheads.

The construction shown was patented in 1894 by Mr. H. Mechan.
Instead of the riveted combination of plate and angle-bar shown in
No. 717, the door is made of a single steel plate pressed hydraulically
between dies which form a shallow recess round the edges ; this recess gives
the door stiffness and also provides accommodation for the renewable
rubber strips that make a watertight joint with the flanged or beaded door-
frame. To obtain closing pressure eight rotative handles spaced round the
door in watertight bushes on the bulkhead, are used in conjunction with
brass shoes or wedges on the back of the door ; the holes in each door-
hinge are elongated to permit of this final adjustment.

719. Model of a deck scuttle. (Scale 1 : 4.) Made by the
Admiralty, 1887. N. 1797.

This shows the method of efficiently closing an opening in a water-
tight deck. The opening is made between two deck beams, and is provided
with a coaming or frame to which the cover is hinged. The joint is made
with india-rubber, similarly to that in No. 717, but is closed by seven hinged
bolts fitted with butterfly nuts.

720. Side scuttles. Lent by the Carron Co., 1890. N. 1847.

These are for providing light and air to the spaces between the decks of
wood or steel-built vessels.

A hole of required diameter is first cut in the shell plating or planking
and to the inner side is secured the outer frame of the scuttle. To this is
hinged a frame carrying the stout glass " light " and a rubber- joint ring
which insures watertightness when closed upon the outer frame. Attached
likewise to the outer frame, but swinging in a different direction, is a solid
metal cover or shutter, similarly jointed, so that should the glass be broken
it will prevent the entrance of water. The hinges are of an adjustable type,
which insure tightness of the joint all round. Hinged bolts with screw nuts
for securing and releasing purposes are provided for each cover.

(a) is an Admiralty pattern scuttle made of gun- metal throughout.
A similar pattern with outer f rame and inner shutter of galvanised cast steel
is also used.

(6) is made of brass, and has a reversible outer shutter. This is fitted
with india-rubber on each side, which adapts it for use with or without
an intermediate glass-light.

(c) has an outer shutter of galvanised cast iron ; the glass also is
bedded upon a rubber cushion.


721. Models of hatchways and coamings. (Scale 1 : 4.) Made
by the Admiralty, 1886. N. 1776-7.

Hatchways are the openings which provide light, air, and a means of
access to the between- deck spaces of vessels ; such openings, when in an
upper deck, are fitted with raised sides or " coamings " of wood or iron to
prevent the passage of surface water from the surrounding deck.

The two models show the usual method of framing a hatchway in an
iron or steel deck; the construction of wood and iron coamings respec-
tively ; the method of securing coamings in position. In each example the
hatchway is formed by fitting " carlings " (or short fore-and-aft beams)
between the ordinary transverse beams of the ship, at the required spacing
apart, and then securing them by short connecting angle-bars at each
corner, riveted as shown.

(a) Here the coaming is of wood, dove-tailed together so as to prevent
any relative movement of the four pieces composing it. Long vertical screw
bolts, disposed as indicated and each secured by a nut and washer beneath
the beam flange, fasten the completed frame to the deck. The transverse
ends of the coaming are provided with a rebate on their inner edges, to
receive a wooden grating or cover.

(6) This coaming is formed of two vertical iron plates bent to form, and
secured to the hatchway framing by means of boundary angle-bars. Butt
straps are shown connecting the two parts of the coaming plates together ;
welded joints are also largely used for this purpose.

Narrow strips of plating, projecting outside the lower edge of coaming
in (a), afford security for the adjacent deck planking ; in (6) the outer
flanges of the beams and carlings are utilised for this purpose.

In ordinary cargo vessels, hatchways are closed by portable wooden
covers, or hatches, provided with lifting-rings at opposite corners. These
hatches are fitted to the coamings of the upper deck hatchways and are
made watertight by a tarpaulin covering ; flush covers are used for the
openings through the lower deck. Large hatchways are usually provided
with shifting-beams and carlings, which give local strength and reduce the
size of the portable covers. The weather hatchways of passenger vessels
are furnished with watertight hoods or covers provided with doors and glass
" lights." In modern war- vessels the large openings for the machinery
spaces are fitted with shell-proof iron or steel gratings, while the smaller
openings in watertight decks and flats are provided with hinged covers fitted
and secured as shown in No. 719.

722. Lithograph of Price's self-trimming hatchways. (Scales
1 : 16, 1 : 48 and 1 : 96.) Lent by Wm. Denton, Esq.,
1876. N. 1454.

This shows longitudinal and cross sections of the S.S. " J. B. Eminson,"
a vessel of 1,031 tons register, 220 ft. long, 31 ft. broad, and 17 '1 ft. deep,
built in 1875 at Sunderland by Messrs. Short Bros. She is fitted with the
hatchways and cargo-shoots patented by Mr. John Price in 1874.

Instead of the sides or coamings of the hatchways being vertical, they
are inclined inboard and supported by the deck beams. The midship
section shows the vessel fully laden with coal or other bulk cargo, for
which the hatchway acts as a feeder, and so prevents trouble from the
cargo settling and shifting. Details are shown of the construction for
vessels of from 26 ft. to 32 ft. beam.

723. Diagrams showing drainage of a battleship. (Scale
1 : 48). Made by the Admiralty, 1889. N. 1799.

These show the drainage arrangements adopted for vessels of the central
citadel type.

A main drain pipe, 12 in. diameter, is placed between the inner and
outer bottom on each side of the vertical keel to receive water from the
spaces above the inner bottom ; these pipes deliver into two cisterns or


sumps, from which the pumps draw. The engine and boiler floors drain
into the main, through horizontal valves attached to short vertical pipes ;
any water from the wing spaces and from those above the third water-
tight longitudinal is similarly cleared. All compartments on the fore
side of the water space forward drain into the bilges, which are levelled
up with cement to the height of the sluice-valves of the main drains.

The " water-balance " chamber and the coal and provision spaces at each
extremity drain into the large " ejector " tanks shown on the fore side of
boiler-room and after side of engine-room respectively. These tanks are
emptied by means of ejectors, a form of steam-jet pump capable of
discharging overboard large quantities of water ; these, however, on account
of their excessive steam consumption, are now superseded by additional
circulating pumps.

The sumps of the main drains are emptied by the suction pipes from
steam and hand pumps. The double bottoms are cleared through separate
" standpipes " connecting each compartment to a valve chest, which is
exhausted by hand pumps. The valves regulating the passage of water
from one space to another are usually actuated by rods extending above
the water-line.

724. Sectional model of ice room. (Scale 1 : 4.) Lent by
the Peninsular and Oriental Steam Navigation Co., 1875.

N. 1400.

This represents a cold store-room, as in use before the introduction of
mechanical refrigeration in 1879, and was fitted in 1875 to the P. and O.
liner S.S. " Cathay," by Messrs. W. Denny and Bros, (see No. 246). Similar
rooms were adopted in other ships, the arrangement being simply an
enlarged ice safe.

The room is placed between the orlop and lower decks. The space
around it is packed with flake charcoal to minimise the conduction of heat
from the outside, while the room is lined with rnatchboarding and sheet
zinc. In one comer is a tank in which collects any water that is formed
by the blocks of ice melting, and is then led off to an adjoining wine-cooling

725. Model of snip's hold, showing cold storage arrangements.
(Scale 1 : 16.) Lent by the New Zealand Shipping Co.,
Ltd, 1908. N. 2476.

This sectional model shows the arrangements for the stowage, preser-
vation, and discharge of meat and dairy produce as adopted on the S.S.
" Papanui," a typical vessel employed in the above company's New Zealand

On one side of the section, in the lower hold, mutton and lamb are
represented packed in bulk ; this system of stowage permits of a satisfactory
circulation of cold air. The freshly-killed animals are first frozen in the
shore depots and then shipped as soon as possible, the vessel having a
storage capacity for about 100,000 carcasses. On the opposite side of the
section are shown boxes of frozen butter and crates of cheese.

The blackened portions of the sections represent the charcoal packing
placed between the frames, floors and deck-beams to ensure the necessary
insulation of holds and 'tween- deck spaces.

The air-cooling and distributing arrangements are by the Linde British
Refrigeration Co. Ammonia- compression machines are used and the
circulated air is chilled by passing over a series of direct- expansion coils
placed in specially-insulated chambers. This cold, dry air is withdrawn by
large directly- driven fans and distributed to the storage spaces by means of
wooden trunks constructed along the sides and floor of the vessel ; by
suitable openings in these air-trunks the temperature is regulated to the
requirements of the cargo, i.e., butter is usually kept at 10-15 F., meat at
22 F. 5 and cheese at 40-45 F.


Rapid discharge of the cargo is effected by a hand or steam-driven
sprocket- chain lift which is fitted with suitable earners and is supported
upon a portable, telescopic frame reaching from the bottom of the hold to
the upper deck; this arrangement was patented by Capt. Gr. H. Noakes
in 1898.

The " Papanui " was built of steel at Dumbarton in 1898 by Messrs.
W. Denny and Bros., her principal dimensions are : Gross register,
6,582 tons ; length, 430 ft. ; breadth, 54 1 ft.

726. Pivot for saloon seats. Lent by the Carron Co., 1890.

N. 1847.

This arrangement permits a limited sliding as well as rotary movement
of the seat of a saloon chair, while the base is firmly secured to the floor.
It was patented in 1887 by Messrs. Cowan and Robertson, and consists of a
circular frame, fixed under the seat of the chair, 'and fitting in an elongated
frame fastened to the base.

727. Models of tables for shipboard. (Scale 1 : 4.) Lent by
H. Burrell, Esq., 1898. N. 2168.

During rough weather it is necessary to fit fences to the dining tables so
as to prevent plates, etc., from sliding off through the rolling motion of the
ship. These fences are usually in the form of light wooden frames, or
"fiddles," resting upon the tablecloth and secured by ledges and straps.
To avoid the inconvenience of using such loose parts, Mr. Burrell in 1888
patented the arrangements shown, in which the fiddles when not in use are
stowed within the table-top.

In (a) the fiddle can sink in a corresponding slot formed through the
table-top, so as to leave the surface flush, while when required for use it can
be raised by cams, actuated by a lever below, and then be retained in
position by suitable catches.

In (6) the table-top is made in panels which can be turned over ; one face
of each panel is provided with raised ledges.

728. Model of fittings for a troopship. (Scale 1 : 8.) Pre-
sented by the Rev. J. Hardie, 1866. N. 1142.

This shows one unit of the arrangement proposed by Mr. R. Blake for
the transport of troops ; it resembles that still used in troop and emigrant

The fittings are temporarily fixed to the deck beams, and to steps on
the deck. There are upper and lower berths, each supplying sleeping
accommodation for three men on boards which fit each of these tiers. In
the day time, these shelves are placed on edge and secured against the sides,
while the middle one is used as a table ; the back and front boards of the
lower berth form benches.

729. Model of horse-stalls for troopships. (Scale 1 : 24.)
Bequeathed by Miss M. A. Peek, 1906. N. 1031.

This shows the original design of Mr. Wm. Ladd, of Deptford Dockyard,
for fitting upper deck horse- stalls on the ships conveying troops to the Crimea
in 1854.

The roofed structure is separated into stalls by loose bars padded on the
inside ; the animals were backed into these stalls so that the mangers were
in the gangway between two sets.

730. Model of early Kingston valve. (Scale 1:4.) Made
in the Museum, 1904. N. 2334.

Upon the application of the steam engine to marine propulsion it
became necessary, for the admission of water to the condenser and feed
pumps, to cut holes through the skin of a ship below the water level. The


arrangement adopted on the earliest steamships for rendering such an
orifice safe consisted of an open cast-iron pipe, passing through the framing
and external planking and fitted with a cock on the inboard end ; these
fittings were, however, difficult to repair while afloat, and any serious defect
in them necessitated dry-docking. About 1837, Mr. W. Kingston, of
Portsmouth Dockyard, introduced the type of valve shown by the model, as
a supplementary valve to boiler blow-off cocks, which had been a source of
trouble, and it was so successful that it was soon generally adopted for all
under-water openings in H.M. ships.

The valve represented was 4 '5 in. diam., and consisted of a gun-metal
pipe, with an enlarged conical end which was carefully fitted into the outer
sheathing and timbers of the ship, and then drawn tightly into place by
means of a large screwed flange on its inner end ; to this was bolted a
separate piece with a branch flange for connection with the blow-on 6 cock.
The valve itself was of gun-metal, and it was seated on the conical portion
of the pipe so that ifc opened outward. It was actuated by hand through a
copper spindle screwed into it and passing through a stuffing box. While
open the valve was supported on the guard-bar below, but when it was
necessary to repair the blow-off cock, the valve was drawn up and so
prevented the entry of water. The valve does not project beyond the
surface of the hull, and, in the event of the spindle breaking, it acts as a
non-return valve. When fitted to hand pumps and injection orifices it was
usually provided with a circular grating and some form of guides ; it was
also capable of being pinned in the open position. Kingston valves are still
used in modern vessels for pumps, evaporators and some of the smaller
openings below the water-line, but, for the larger orifices they are being
generally displaced by the lighter and cheaper form of screw- down valves.

The model shows also a portion of the ship-structure around the valve,
with the bottom planking, transverse wooden framing, valve chock, and
fastenings as usually arranged ; a strip of copper was placed between the
lower end of the tube and the bottom planking to protect the latter against
ship worms.

731. Model of Kingston valve. (Scale 1 : 4.) Made in the
Museum from drawings supplied by the Admiralty, 1903.

N. 2332.

This represents a Kingston valve of 8 ' 5 in. diam. as now fitted to the
plating of a steel-built vessel at the sea-suction inlets of the hand pumps,
and in some cases at the outlets of the blow-off pipes from boilers and

Like the earlier example No. 730, the valve is conical and opens outwards,
so that it can be repaired from outside the ship while, should the spindle
break, it will act as a non-return valve. The valve and casing are, however,
considerably lighter than in the earlier form, and the spindle and valve are
made in one piece, while guides are added to steady the valve throughout
its whole travel ; the valve box is, moreover, provided with a flange by which
it can be directly secured to the outer bottom of the vessel or, if necessary
for convenience in connecting the pipes, a distance piece may be inserted as
shown in the model.

The valve spindle passes through a gland in the valve-box crown and its
projecting end is cut with a right-handed square-threaded screw which
engages with a nut formed through the boss of a mitre wheel. This wheel
is rotated by a similar one secured to a shaft which is led to some convenient
position above the water line of the ship, so that the valve can be closed
even when the lower decks are flooded; at this operating station is an
indicator deck- plate showing the extent to which the valve is open. The
mitre gear is carried by a double bracket fixed to the valve casing, and a
collar secured by a set-screw retains in position the screwed boss of the
wheel forming the nut, while a stop, fitting in a slot cut along the screwed
portion of the spindle, prevents the rotation of the valve when the gear is


turned. There are two flanged outlets from the valve box, one being for
the pump suction-pipe and the other for a flooding or other pipe.

To secure the valve-box, or the distance-piece, to the ship's skin, a
facing-ring is riveted round the opening in the bottom plating, and to this
the lower flange is fastened by means of studs and nuts of naval brass ; a
grating is also provided to this opening which checks the entry of weeds,

Online LibraryScience Museum (Great Britain)Catalogue of the naval and marine engineering collection in the ... museum .. → online text (page 30 of 58)