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gave almost absolute immunity from danger in the event of
grounding. This system has since, with slight variations, been
almost universally adopted for all large battleships and cruisers,
and in a large number of ocean-going merchantmen. Solid
plate floors combined with longitudinal frames and stringers
form a modification of the bracket system which has also been
largely used in the construction of smaller vessels for the Royal
Navy and mercantile marine, and for framing the extremities
of large warships.

Steel began to be generally used for shipbuilding in 1878,
and a series of tests made during 1878-9 at Chatham led to its
adoption by the Admiralty. The revival of the ancient mode of
attack by ramming, and the increasing demands for high speed,
necessitated special structural arrangements at the bow and
stern, which led to a further application of steel. Several
forms of stem and stern-posts, with their connections, are among



185

the exhibits, from which the great change made possible in
this direction by the use of cast steel can be seen by contrasting
the simple iron forgings of early vessels with the elaborate stern
castings of later constructions.

Armour. War-vessels are usually protected from gun attack
by side and athwartship vertical armour, by horizontal or
curved protective decks in the region of the water-line, and by
side spaces generally packed with coal. Protection against ram
and torpedo attack is largely given by efficient and extensive
sub-division of the lower portions of the hull, aided in the latter
case by torpedo " defence-nets " suspended outside the ship.

The French warship "La Gloire," completed in 1859, was
the earliest sea-going ironclad ; she was wood-built, and carried
a complete belt of side armour 4' 5 in. thick, secured by long
bolts to a massive wooden framing 26 in. thick. The British
' Warrior" of 1861 was an iron-built vessel with a partial
belt of 4'5-in. iron armour, backed with 18 in. of timber
and an inner iron skin. At this time many wooden ships
also were cut down and fitted with side armour. In 1865,
H.M.S. " Bellerophon " was built of iron with a complete belt of
6-in. armour; the "Hercules," in 1868, had 9-in. plates, and
the " Dreadnought," of 1875, had 14-in. plates. The power of
naval guns, however, increased more rapidly than the resistance
of the armour. To provide the thickness necessary for pro-
tection, without giving abnormal dimensions to the vessels, the
extremities were left comparatively unprotected and the weight
so saved expended in a heavily armoured central citadel.
This construction of armour-clad vessels reached its maximum
in 1881, when H.M.S. " Inflexible " was fitted with side plates
of iron 24 in. thick. Compound iron and steel armour was
in general use until about 1889, and was superseded by the
"Harvey," the "Rrupp," and other forms of hard-faced steel
armour ; the increased resistance to penetration offered by these
latter has been an important factor in the general reduction
of maximum thickness and in the extension of the armoured
area. Recent British battleships (1910) have an all-round
armoured protection varying from about 11 in. amidships to
about 3 in. at bow and stern. In 1897 it was concluded . that
14 in. of solid wrought iron armour was equalled by 11 in.
of compound, or by 6 or 7 in. of hardened nickel-steel armour.
It was found, however, that the new armour required additional
supporting, and this has been arranged by the introduction of
specially deep web-frames and horizontal girders behind the
armour.

The idea of carrying heavy guns in revolving armoured
shields or turrets, thus obtaining good protection and a wide
range of fire, was first adopted in the Royal Navy on the wood-
built " Royal Sovereign" and iron-built "Prince Albert" in
1862. Since 1878, turrets, or their modern development,
"barbettes " with a protective ring of stationary armour have
been used to carry the main armaments of all first-class



186

battleships. Where secondary batteries of large quick-firing
guns are adopted, they are usually protected by some form of
casemate or armoured redoubt ; heavy armour gratings and light
splinter-nets are also used to protect openings in the upper decks.
Recent naval engagements have demonstrated the necessity
for avoiding the use in the interior fittings of a warship of
all combustible material.



WOODEN SHIP CONSTRUCTION.

608. Built models of wooden ships. (Scales 1 : 48 and 1 : 24.)
Lent by T. Royden, Esq., 1876. N. 1428.

The first represents the framing of a three-masted wooden merchant- ship,
with the square stern common at the beginning of the 19th century. The
second shows a single-masted vessel. In both cases the frames are open-
spaced and built up of two sets of timber.

609. Half block model of stern of a three-decker. (Scale 1 : 24.)
Presented by the Rev. J. Hardie, 1866. N. 1123.

This shows the starboard side of the stern of a battleship, arranged
according to Mr. R. Blake's proposal for obtaining |a right-aft as well as a
quarter line of fire,

610. Half block models of sterns of three-deckers. (Scale 1 : 48.)
Presented by the Rev. J. Hardie, 1866. N. 1103.

The starboard half shows a proposal by Mr. R. Blake for fitting elliptical
stern- galleries to a first-rate man-of-war ; the port half shows details of the
framing of a similar stern and also a method of working the external
planking above the counter to add strength to this arrangement.

611. Model of bows of frigates. (Scale 1 : 24.) Presented by
the Rev. J. Hardie, 1866. N. 1127.

The topsides are shown completely planked, while the lower portions
illustrate two different dispositions of frame timbers with their temporary
fairing battens or harpins. The starboard bow shows the foremost frames
canted, snaped at the heels, and stepped into the stem piece. The port side
shows the frames worked with their moulding in a fore-and-aft plane, and
stepped into the foremost canted frames a system largely adopted for
bluff-bowed vessels.

612. Half block model of sterns of three-deckers. (Scale 1 : 48.)
Presented by the Rev. J. Hardie, 1866. N. 1125-6.

The first shows the starboard side of a square-sterned vessel, with some
of its vertical stern-timbers stepped into the fashion-piece, and some carried
by means of snaped heels the full depth of the stern.

The second is an alternative arrangement, in which by the use of
transom-timbers the work is simplified and the loss in timber conversion
reduced.

613. Stern model of a three-decker. (Scale 1 : 24.) Presented
by the Rev. J. Hardie, 1866. N. 1124.

This shows very completely the above-water stern construction of a
first-rate line-of-battle ship of the beginning of the 19th century.



187

The port side shows the disposition of the frames, ports, wales, and
framing of the galleries, while the starboard side shows the finished stern.
"With this design an all-round fire is obtained.

614. Drawing of framing of H.M.S. "Amethyst." (Scale 1 : 96.)
Presented by J. Scott Tucker, Esq., 1865. N. 1048.

This shows the disposition of the port timbers of this 28-gnn frigate,
in which the frames were continuously bolted together in the manner
introduced by Mr. J. Tucker. She was wrecked in Plymouth Sound in
1811, but after being 21 days on the rocks was floated off with unbroken
sheer.

615. Block model of sterns of three-deckers (Scale 1 : 48.)
Presented by J. Scott Tucker, Esq., 1865. N. 1051.

This shows a design proposed by Mr. J. Tucker in 1808. The starboard
half shows the old arrangement of square stern, while the port side represents
his slightly curved stern, which allows quarter gun-ports on each deck.

616. Built model of a merchant ship. (Scale 1 : 64.) Lent by
Lloyd's Register of British and Foreign Shipping, 1876.

N. 1437.

This represents a square -sterned ship pierced for 50 guns, possibly an
East Indiaman. Details are given of the amidship, stern, topside and deck
framing, of external planking and ribbands and of bowsprit and lower
masts.

617. Models of deck and frame fastenings. (Scale 1 : 16 and
1 : 48.) Presented by J. S. Tucker, Esq., 1865.

N. 1049-50.

These show proposals by Mr. J. Tucker, Surveyor of the Navy
1813-31, for fastening deck planking from the under side by wood screws.
For this purpose overhanging strips are nailed to the beams and screws
inserted through the projecting flanges ; intermediate binding strips are also
worked between each pair of beams.

The smaller scale model, of a portion of the midship framing of a vessel,
illustrates a method of shifting the butts of frame-timbers and of securing
them together by dowels and metal bolts ; it also shows the scarfing of
deck-beams, as well as the fastening of deck-planking, on the above system.

618. Model of built-up ship's knee. (Scale 1 : 8.) Presented
by the Rev. J. Hardie, 1866. N. 1144.

Owing to the difficulty in obtaining sufficient naturally-bent timber
knees, ships were frequently delayed during construction. This design by
Mr. R. Blake shows a built-up timber knee of considerable strength. The
two portions are connected by a pair of five-tongued tenons secured by pins
and stayed with iron straps and bolts. Iron knees, however, displaced all
such devices.

619. Models of futtock timbers. (Scale 1 : 6.) Presented by
the Rev. J. Hardie, 1866. N. 1116-8 and 1132-3.

These show several of the methods introduced by Mr. R. Blake for
forming the curved futtocks of wooden frames from two pieces of straight
timber when, as was frequently the case, naturally bent timber was not
available. To minimise waste the joint is made in the sharp turn of the
ship's bilge ; the two pieces are connected either by means of the " chocked
butt " joint seen in one model or by scarf joints as shown in two others.
Two more show details of the connections, which are secured by bolts and
dowels.



188

620. Models of deck-beam fastenings. (Scales 1:8, 1 : 12 and
1 : 16.) Presented by the Rev. J. Hardie, 1866. N. 1112.

These show various methods employed for securing deck-beams to a
vessel's frames. They were made between 1806-55 by Mr. R. Blake,
master shipwright in H.M. Dockyards.

(a) Is an early arrangement in which the beam is supported on clamp
strakes to which the wooden knee is bolted ; the knee and beam are further
secured by iron plate knees on each side, with bolts so distributed as to
be in different lines of fibres, an arrangement due to Mr. Roberts, master
shipwright.

(6) Here a " shelf" takes the place of one clamp strake, the wooden and
plate iron knees being replaced by iron lodging and hanging knees.

(c) Shows a similar arrangement applied to orlop and lower deck beams,
with the addition of Sepping's diagonal trussing.

(d) Is the latest and most extensively adopted arrangement. The shelf
is lightened by chamfering, and a waterway is added above the beam, while
horizontal lugs are provided to take the fastenings of the iron hanging
knees.

621. Models of floor timbers. (Scales 1 : 16 and 1 : 8.)
Presented by the Rev. J. Hardie, 1866.

N. 1119-22, 1131 and 1135.

These illustrate various methods introduced by Mr. R. Blake for forming
and fitting floor timbers, i.e., the lower portions of wooden frames.

(a) This is a short angular floor as fitted to the finer extremities of the
ship. The two arms are formed of a single piece of timber, provision being
made at the lower part for fixing two tapering chocks one on each side of
the keel ; this arrangement obviates the weakness arising from the scoring
or cutting away of the floor timber over the keel, the practice otherwise
followed. Two of the models show similar floors with the side chocks in
position.

(6) This is shown in place upon a wooden keel, and represents a floor of
similar dimensions to the above, but formed by scarfing two straight pieces
across the middle line of the ship.

(c, d, e) These show on a reduced scale methods of fitting floor timbers
at the wide and flat portions of a vessel. Each complete floor is here
composed of two sets of timbers, the joints in each being covered by the
sides of the adjacent set. These models also illustrate two methods
extensively adopted for securing the heads and heels of timbers, those shown
with snaped ends providing for a chocked butt connection, while the other
shows a plain butt-and-dowel joint.

(/) This is an example of a floor frame bent by mechanical means. The
straight timber is rendered flexible by immersion in steam, and the outer
ends turned to the required shape, a saw-cut made through the neutral
plane of the timber facilitating this process. Through bolts, placed as
shown, assist in retaining the curvature thus obtained.

(g) This is a portion of a wooden keel, showing the rebate formed to
take the lower edges of shell planking, also details of the " letting down "
process whereby one-half of the scoring is taken from the floor timbers, and
one-half from the upper surface of the keel, thus forming a secure
combination without unduly weakening either member.

622. Half block models of bows of three-deckers. (Scale 1 : 48.)
Presented by the Rev. J. Hardie, 1866. N. 1128-9.

The first model represents the starboard bow of a first-rate line-of -battle
ship of the period 1835-40 ; this has a total bow fire of 8 guns.

The second shows the port bow of a similar ship of about 1840-50,
arranged on Mr. R. Blake's plan to obtain a bow fire of 12 guns.



189

623. Model of port-lids with inboard fittings. (Scale 1:8.)
Presented by Rev. J. Hardie, 1866. N. 1107.

This shows a method proposed by Mr! R. Blake for fitting and fastening
the upper and lower lids, or shutters, to gun-ports.

Each lid is vertically hinged inboard and both secured, when closed, by
cotter pins. A circular gun-aperture in the centre of the port provides
ventilation between decks in ordinary weather ; this, however, is filled by a
solid wooden block in rough weather, and the whole securely held by a
central hinged bar.

624. Model of lower deck port. (Scale 1 : 16.) Presented
by the Rev. J. Hardie, 1866. N. 1130.

This shows a method of constructing a gun port of a wooden line-of-
battle ship. The several eye -bolts are for attaching the tackle used in
working the guns.

625. Model of wooden protective belt. (Scale 1 : 20.) Pre-
sented by the Rev. J. Hardie, 1866. N. 1134.

This shows a lower deck port and the side of a wooden ship-of-war, fitted
with a protective belt along the water-line, as proposed by Mr. B. Blake.
The belt has a maximum thickness of 20 in., and tapers in each direction.

626. Model of stern framing of a merchant ship. (Scale 1 : 32.)
Lent by the Nelson Dock Co., 1876. N. 1444.

This shows the method of framing the square sterns of the East India-
men of about 1820.

627. Built models of a wooden ship. (Scale 1 : 48.) Lent
by Lloyd's Register of British and Foreign Shipping, 1876.

N. 1432-3.

The fore and the after body of a two-decked merchant ship are here
shown separately ; on the port side of each the inner and outer planking,
with fastenings, are complete, while on the starboard side the frames are
seen, held together by temporary ribbands. Some of the hanging iron knees
are extended to the deck beams below them.

628. Model of midship section of H.M.S. " Rodney " (1833).
(Scale 1 : 24.) Presented by F. W. Slade, Esq., 1903.
Plate VII., No. 1. N. 2340.

The " Rodney" was originally a two-decked sailing line- of -battle ship of
92 guns, designed by Sir R. Seppings and launched at Pembroke in 1833.
The model shows the va.rious decks and the interior of the main hold of the
vessel, together with the general arrangements for the stowage of water- tanks
and provisions ; also the principal features of the system of wooden ship
construction followed at the time.

Amongst the structural details represented are some improvements
introduced by Sir R. Seppings in 1813-32 while he was Surveyor of the
Navy ; these include :

(1) The employment of a system of internal diagonal timber ties,
crossing the frames at 45 deg. and fitted between themselves with corre-
sponding struts ; the panels thus formed were further stiffened by the

. insertion of longitudinal timbers, so that the whole arrangement converted
the hull into a completed trussed structure. By this construction the
requisite strength was obtained with considerably less weight than was
necessary in the earlier system with its massive vertical riders and internal
planking.

(2) The method of connecting the heads and heels of the timbers
composing the transverse frames, by plain butts with circular dowels or
plugs instead of by the various methods of scarfing previously in use.



190

(3) The introduction of thick continuous "waterways'' and " shelf -
pieces," placed respectively above and below the ends of the deck beams, to
secure better connection of the beams with the sides of the vessel and also
additional longitudinal strength.

Other details shown are : The use of forked iron knees to the beams ;
the arrangement of pillars or stanchions for supporting the decks ; and the
varying thicknesses adopted for different portions of the external planking.
A number of the strakes of planking near the water-line are shown cut on
the " anchor- stock " system, which gave an increase of structural strength
while reducing the waste in timber conversion. On the orlop deck are
shown the hemp anchor cables, used before the introduction of chain cables ;
the planking of this deck is worked in short pieces between the beams.

The " Rodney " took part in some trials of sailing ships-of-the-line during
1845-6, and proved herself to be superior to her contemporaries in speed
and steadiness during rough weather ; in 1860 she was converted into an
auxiliary screw- ship.

Her original dimensions were : Burden, 2,626 tons ; length, 205 -5 ft. ;
breadth, 54 -5 ft. ; depth, 23-1 ft.

629. Half model of wooden paddle steamer. (Scale 1 : 48.)
Lent by the Nelson Dock Co., 1876. N. 1443.

This represents the framing of a square- sterned paddle steamer, designed
about 1840. On each side of the paddle-wheel position the topsides are
given considerable " flare," thus increasing the deck area and weatherly
qualities.

630. Longitudinal section of a merchant ship. (Scale 1 : 32.)
Lent by Lloyd's Register of British and Foreign Shipping,
1876. * N. 1431.

This is a square-stemed two-decked merchant ship, and has the leading
details distinctively labelled. It represents the later form of wooden
construction, in which the knees and most of the pillars are of iron.
The lower beams are not decked over, except at the forecastle, as they
are only introduced to strengthen the hull.

631. Half model of ship with radiating frames. (Scale 1 : 64.)
Lent by Lloyd's Register of British and Foreign Shipping,
1876. " N. 1434.

This shows a wooden ship of about 800 tons, with poop deck and
forecastle. The frames radiate to a point about amidships, so that while
the frames there are vertical, the others incline on both sides more and
more as the bow and stem are approached. The inclined frames assist in
resisting the shearing stresses.

632. Half model of diagonally-sheathed vessel. (Scale 1 : 48.)
Lent by Lloyd's Register of British and Foreign Shipping,
1876. N. 1435.

This shows a wooden merchant vessel, sheathed with planking laid
diagonally at about 45 degs. in one direction at the bow, and with the
opposite inclination at the stern, the intermediate triangular space being
sheathed vertically.

633. Half midship section of a wooden corvette. (Scale 1 : 24.)
Received 1874. N. 1393.

This represents the midship framing of a frigate, and shows in detail the
improved method of wooden construction adopted in H.M. Dockyards after
1840.

Three tiers of deck beams are shown with their shelves and waterways,
together with the wrought iron securing knees. Two complete frames.



191

together with the intermediate filling pieces, are represented, and the model
shows how, by breaking joint, the continuity of strength is secured. The
butts of the timbers are dowelled together, instead of being connected by
scarfs or chocks as formerly. Sections of keel and keelson are shown and
also portion of the inner and outer planking.

634. Half block model of H.M.S. " Caledonia," (Scale 1 : 48.)
Lent by Geo. Turner, Esq., 1864. N. 1036.

This vessel was commenced as a wooden battleship of 91 guns, 3,716 tons
and 800 h.p., but before completion was changed to an armoured frigate
carrying 36 guns. Several other vessels were similarly converted in 1862-4.

Diagonal iron riders are shown fitted all fore-and-aft outside the framing
instead of inside as originally arranged : these gave increased structural
strength to the vessel and, by being arched over each gun-port, added local
strength to these positions.

The length of the battery was 280 ft., and its armour plates were 4-5 in.
thick, backed with 30 in. of oak ; the weight of the armour was 930 tons.

Her engines, by Messrs Maudslay, Sons and Field, were of the horizontal
return-connecting-rod type, with two cylinders 92 in. diam. by 4 ft. stroke,
and when making 57 revs, per niin. indicated 4,092 h.p. with 20 Ib. boiler
pressure.

The screw propeller had four blades, and was 21 ft. diam., while the pitch
could be varied from 20 ft. to 25 ft. ; it could be disconnected from the
engines by means of a clutch. Her trial speed was 13 knots.

Displacement, 5,800 tons: burden, 4,125 tons; length, between perps.,
273 ft. ; breadth, extreme, 59 '2 ft, ; draught forward, 23 -5 ft. ; draught aft,
26 '7 ft. ; immersed midship section, 1,050 sq. ft.

635. Gunwale of steel boat. Presented by Messrs. R, Napier
and Sons, 1867. N. 1185.

This was designed by Vice- Admiral E. P. Halsted, R.N., for the boats of
his proposed warships. The boat was to be of steel, but was to have a
wooden fender secured by angle irons.

636. Shell planking and framing of motor boats. Lent by
James A. Smith, Esq., M.I.N.A., 1906. N. 2424*.

Wood, in preference to steel, has been largely adopted for the construction
of high-speed motor craft under 50 ft. in length, the principal advantages
claimed being less weight and cost, fairer surfaces and better combination
of parts.

Five examples are here shown of various methods of forming the outer
skins or shells of wood-built boats : they were made to illustrate a paper
on " The Design and Construction of High-Speed Motor Boats " read
by Mr. James A. Smith before the Institution of Naval Architects in
April 1906.

No. 1 shows the ordinary carvel system with bent timbers or frames ;
this has single planking of mahogany with caulked seame and timbers of
rock elm and is used for ordinary types of motor launches where weight is
not of the first importance.

No. 2 shows double planking of mahogany without timbers, the outer
skin being worked fore-and-aft and the inner skin diagonally ; it is used for
light dinghies, yachts, and racing launches up to 25 ft. in length.

No. 3 is the same as No. 2, but reinforced by timbers of rock elm. It is
commonly used for high-powered racing launches.

No. 4 shows the ribband- carvel system : the single planking is of
mahogany with timbers of rock elm, but the edges of the planking are
covered on the inside by longitudinal ribbands which are scored over the
timbers. It is occasionally used for high-powered motor craft.

No. 5 shows the sewn skin without timbers patented in 1898 by
Mr. S. E. Saunders. It may be constructed of two, three, four or more



192

thicknesses, each thickness being worked separately and the whole finally
sewn together with copper wire. This makes a strong combination which is
easily adaptable to difficult curves and is used for steam and motor launches
of all types.



637. Blake's screw. Presented by the Rev. J. Hardie, 1868.

N. 1110.

This is a form of iron eye-bolt, introduced by Mr. R. Blake, for use in
temporarily securing harpins and similar timbers to the frames of wooden
vessels while under construction. A hole is bored through the harpin and
frame, and then this screw inserted, the eye-end facilitating screwing-up.
As originally made these screws have their shanks of smaller diameter than
the threads, as shown, so that some slight adjustment of the harpin was
possible after the screw had been inserted ; the modern Blake's screws are,
however, parallel throughout. They are made in various lengths, and the
diameter varies from 75 to 1 25 in.

638. Screw auger and dowel-engine. Presented by J. Scott
Tucker, Esq., 1865. N. 1055.

These wood-boring tools were introduced by Mr. Joseph Tucker, Sur-
veyor of the Navy, 1813-1831, as improvements on the ordinary shell



Online LibraryScience Museum (Great Britain)Catalogue of the naval and marine engineering collection in the ... museum .. → online text (page 26 of 58)