Science Museum (Great Britain).

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

. (page 51 of 58)
Online LibraryScience Museum (Great Britain)Catalogue of the naval and marine engineering collection in the ... museum .. → online text (page 51 of 58)
Font size
QR-code for this ebook

ment allows a much larger portion of the circumference of the cable-holder
to grip the cable than in the type illustrated, but this advantage has been
sacrificed in order to obtain the inclined direction of the out- going cable.

The main bearings and standards form part of the bed-plate and the
standards also contain bearings for the intermediate shaft. The engines are
of the vertical type with a cylindrical reversing valve (on the model the
chest of this vaive is shown in section). Reversal is effected by inter-
changing the steam and exhaust ports of the cylinder valves. This is
accomplished by altering the position of the reversing valve by means of a
screw and hand-wheel.

On the crank- shaft is a steel pinion gearing into a shrouded spur wheel
on an intermediate shaft. This shaft also carries two steel pinions gearing
into large purchase wheels with shrouded teeth, keyed to the main windlass
shaft. A very large mechanical advantage is thereby obtained. To prevent
the windlass taking charge, i.e., being pulled round by the strain on the
cables, each of the purchase wheels is fitted with a monkey pawl consisting
of two wrought-iron side plates with flanges projecting inwards to overlap
the flanges of the purchase wheel. Two small bolts hold the plates loosely
together, whilst a large bolt forms the axis of the pawl lever. The pawl
allows the purchase wheel to revolve in one direction only ; when it is


required to reverse the windlass, the pawls are tripped, i.e., lifted out of
action by means of cams placed underneath them, which are worked by a
lever at the side of the windlass.

The cable-holders on the main shaft are fitted with frictional disc
'connectors (one of which is shown in section on the model), patented by
Mr. T. A. Weston in 1863, and modified by Mr. Harfield in order to adapt
them to windlasses. Each connector consists of 16 discs alternately
connected to the cable-holder and to the boss of the purchase wheel by
feathers. Tightening is effected by a hand-wheel, which, with a square-
threaded brass sleeve loose on the shaft, forms a screw fixed in position.
The nut consists of a circular plate connected with another plate at the end
of the frictional discs, these two plates enclosing and gripping the discs,
when the hand-wheel is rotated. By this means, each of the two cables can
be worked independently ; also, the cable-holders rotate idly on the shaft
when the frictional connectors are free. Strap brakes are fitted to the
cable-holders to enable the cables to be checked when veering. Barrels are
fitted to the intermediate, or counter shaft for quick warping.

This type of windlass is made in sizes suitable for cables of from 75 in.
to 3' 125 in. diam., corresponding to pulls of from 3 to 60 tons. The model
represents a windlass giving a pull of 30 tons at a speed of 30 ft. per min.,
and using a cable of 2-625 in. diam., as fitted to the R.M.S. " Amazon."

1070. Model of picking-up gear for cable ship. (Scale 1 : 12.)
Received 1909. N. 2531.

In this gear, for hauling inboard a faulty submarine cable, a winding
drum receives motion, by means of toothed gearing', from a steam engine
with two inclined cylinders. On the engine shaft there are two wheels of
different diameters cast together, which can be moved along a feather by
means of a hand lever, and either wheel thrown into gear with its corre-
sponding wheel on a second shaft, on one end of which is a pinion gearing
with an annular wheel on the drum. This arrangement allows alternative
speed reductions of 12 to 1 or 20 to 1 to be employed according to the
nature of work to be executed. The drum is fitted with a powerful band
brake which is controlled by a hand wheel.

The cable comes inboard over the bow sheave and, after passing over a
guide sheave and under a sheave on a dynamometer which indicates the
tension, makes three or four turns round the drum, whence it proceeds over
a hauling-off sheave to the cable tank. The last sheave is so connected with
the drum by gearing that its circumferential speed slightly exceeds that of
the drum, while fitting into a groove on the sheave is a jockey wheel mounted
on a lever carrying a weight. A pulling action is thus exerted on the cable
which ensures that it is kept taut. To prevent the cable winding itself
across the drum a fleeting knife not shown in the model is provided.
This has a curved face and is placed near the drum on the side to which the
cable is fed and continually moves the coils sideways across the drum.

On repair ships this gear is also employed for paying- out cable from the
bows. For this purpose the engine is disconnected from the drum, and as
the hauling-off sheave must now hold back the cable to keep it taut, the
circumferential speed must be less than that of the drum. It is conse-
quently thrown out of gear with the latter and controlled independently by
a small brake.



Anchors. The earliest form of anchor was a stone or other
weight to which a rope was secured, so that when resting 011
the bottom it was capable of offering sufficient frictional
resistance to prevent a vessel from drifting. By enclosing the
stone in a wooden frame provided with projecting teeth, as
shown in some of the Chinese models, an additional ploughing
action was secured which greatly increased the holding power ;
in all modern anchors the design is such as to insure this action
under all circumstances.

The principal parts of an anchor are : the vertical stem or
"shank," the "arms" with their terminal blades or " flukes,"
and the cross-bar or " stock " which prevents the anchor from
being dragged flat-ways along the bottom.

An anchor of about B.C. 50 was constructed of lead, but was
of the ordinary shape except that the ends of the arms were
not widened out into flukes ; after the general introduction of
iron for anchors but little further change took place till the
present century, when the introduction of the steam hammer
and the employment of ingots of mild steel facilitated the
construction of larger types.

In addition to the common form of anchor, however, many
descriptions of "patent" anchor have been introduced, some
of which are now very extensively adopted. One of the most
common of these has the two arms as a separate forging pinned
to the shank so that it can swing to some extent ; in this way
a good bite is obtained, while the upper fluke is occupying a
position in which the chance of its being fouled by the cable
is greatly reduced. This arrangement was first patented in
1838 by W. H. Porter, and was subsequently improved by
J. Trotman and others.

Another class of "patent" anchor is the "self-canting,"
and therefore usually "stockless," variety in which the arms are
so swung that they can both bite into the ground together.
The first anchor of this type was patented in 1821 by
R. F. Hawkins, but it was many years later before such an
arrangement was successfully introduced. An incidental
advantage of these anchors is their great compactness and the
consequent ease with which they can be stowed.

For mooring purposes, the wedge clump anchor (see
No. 1093) has been found satisfactory. This type of anchor
gives good holding power in soft muddy bottoms.

The size of anchors has steadily increased ; the bower
anchors of the " Great Eastern" each weighed 5*4 tons, while
the centre bower anchor of the " Olympic" weighs 15 '5 tons,
and the two side anchors 8 tons each ; the sheet and spare
anchors in H.M. Navy usually weigh 5 tons each.

Anchors only possess considerable holding power if the pull
of the cable is nearly horizontal, so by hauling in the cable


until the pull becomes more nearly vertical an anchor breaks
from its ground and can be lifted.

Cables. The earliest cables appear to have been of hide or
animal membranes, then of flax or hemp, and possibly some
were of bronze chain ; in modern times cotton, hemp and jute
have been used, but iron chain is the material now generally
adopted. Such iron cable was tried and advocated by
Commander Sir S. Brown, R.N., about 1810, but it met with
great opposition largely due to its uncertain quality ; he,
however, in 1812, constructed a machine for testing the links,
and generally developed the manufacture of chain into a
successful industry.

The cable in general use is of either the short link or the
stud link variety ; in the former the links are so short that
there is only sufficient room in them for the loops of the
adjacent links, while in the stud link the length is increased
by the diameter of a transverse stud which, in addition to
keeping the links in their correct positions, also struts the
longer link thus permissible. The stud chain is considered
to be 10 per cent, lighter than the close chain of equivalent

1071. Models of Belcher's anchors. (Scale 1:12.) Contributed
by Admiral Sir E. Belcher, K.C.B, 1876. N. 1455-6.

This anchor was designed in 1815 by Sir E. Belcher, then a midshipman.
The two arms are forged together, and turn in a fork formed in the shank,
as in the Porter anchor introduced in 1838 ; but the form of the arms does
not reduce the risk of fouling, as does that of Mr. Porter. Another model
shows a temporary anchor, prepared from one of these pairs of arms, three
kentledge blocks, and a shackle.

1072. Model of Hawkins's anchor. (Scale 1 : 12.) Presented
by the Commissioners of Patents, 1863. N. 886.

This anchor, patented by Mr. R. F. Hawkins in 1821, introduces the
leading features of most of the modern stockless anchors. The shank
terminates in a large eye, through which the forging forming the two arms
is passed ; the flukes are then inserted in the ends of the arms and secured.
A separate pair of arms keeps the main arms in position, and also forms a
pair of toggles which causes the flukes to dig into the bottom ; the toggles
also acted as stops to limit the cant of the arms. Hawkins pointed out
that by the arrangement both flukes were utilised, the anchor required no
stock, and that the risk of fouling was obviated. The anchor was not
appreciated at the time, although its features are now found in several
leading forms.

1073. Model of Admiralty pattern anchor. (Scale 1 : 12.)
Presented by the Lords of the Admiralty, 1864. N. 1004.

This is generally known as Sir W. Parker's anchor, and was introduced
into the Royal Navy about 1840, replacing the old long- shanked anchor,
upon which it was a slight improvement. The arms are curved and the
length of the shank is three times the length of each arm. The stock is
formed of two beams of oak, hooped together ; the spare stocks, which were
always carried, were frequently used for " fishing " masts and similar
repairs. The largest of these anchors weighed five tons.


1074. Model of Rodger's hollow-shanked anchor. (Scale 1 : 4.)
Presented by Lieut. Wm. Rodger, R.N., 1857. N. 81.

This modification of the Admiralty old pattern anchor was patented by
Lieut. Rodger in 1828. Instead of a solid shank, it has a shank formed in
two bars, the space between them being filled with a piece of oak ; the
compound member is then clamped together by wrought-iron hoops. A
25 cwt. anchor of this style was constructed, but the arrangement was not
generally adopted.

1075. Models of Rodger's anchors. (Scale 1 : 4.) Presented
by Lieut, Wm. Rodger, R.N., 1857. N. 82-4.

These four models illustrate modifications in the Admiralty anchors,
patented by Lieut. Rodger between 1833 and 1846. At the earlier date he
proposed using very small spade-shaped palms, and one model shows for
comparison an Admiralty anchor in which one of the palms has been reduced
as proposed. The other models show modified palms in which the size is
increased ; they are similar to the then Admiralty pattern, but the flat face
of the flukes is outside. A metal stock of triangular section is used, in
which one flat face is uppermost ; the stock is also forged with an eye
through which the shank is passed aud then secured with a cotter.

1076. Model of protected anchor. (Scale 1 : 12.) Presented
by the Commissioners of the 1851 Exhibition. N. 446.

This anchor, patented in 1836, is of the usual pattern, but has two iron
rods running from the corners of the palms parallel with the arms, so as to
reduce the probability of the cable fouling the upper fluke. A similar
anchor was introduced by Mr. Isaacs, and tested in the official experiments
of 1852.

1077. Models of Aylen's anchor. (Scale 1 : 6.) Presented by
Capt. J. Aylen, R.N, 1862. N. 814-5.

These two modifications of the Admiralty pattern anchor were tried
in some official experiments in 1852 ; the results were considered to be
somewhat better than those obtained with the standard form, from which,
however, the designs but very slightly differ.

1078. Model of Trotman's anchor. (Scale 1:8.) Presented
by J. Trotmaii, Esq., 1862. N. 817.

This very successful anchor was patented by Mr. Trotman in 1852,
as an improvement on the anchor patented by Mr. W. H. Porter in 1838,
which patent was subsequently extended for six years. The arms are forged
in one piece, which is earned on a pin that secures it in a fork formed in
the lower extremity of the shank ; this arrangement allows the lower fluke
to dig deep into the ground, while the upper one closes down on to the
shank, and so reduces the chances of fouling and other risks. The improve-
ment introduced by Mr. Trotman consisted in forming the palms with
large external projections, which insured that the arm canted in the way
necessary for holding.

The model represents a bower anchor of H.M. yacht " Victoria and
Albert," but to a scale of 1 : 12 it would represent one of the bower
anchors of the " Great Eastern," weighing 5*4 tons.

1079. Model of Roberts's anchor. (Scale 1 : 12.) Contributed
by Richard Roberts, Esq., 1858. N. 175.

This construction of anchor was patented by Mr. Roberts in 1852.
The leading feature of the arrangement is that, instead of making the
anchor of solid forgings, it is built up of thick plates, riveted together


but separated by distance pieces. The arms are formed of two plates,
and the palms by two other plates riveted to them ; the shank is of two
plates, connected by distance pieces, and at the upper end twisted in such
a way that the stock, which works between them, shall, when lowered, be in
the same plane as the arms, so as to reduce the space occupied. The arms
are of the oscillating type introduced by Mr. Porter.

1080. Martin's anchor. Contributed by E. Rettig, Esq., 1860.

N. 444.

This is a small example of the early form of anchor patented by
Mr. F. Martin in 1859. The shank is forged with a fork at the lower end, in
which are large eyes through which the arms can be passed. In the jaws
of the fluke is placed a " throat piece," into which a projection of the
arm engages, so that this piece forms a stop for the arms. The arm
forging is prevented from moving sideways by two side plates, while
projections on the throat piece secure the canting of the flukes. At the
upper end of the shank is a small curved stock, cottered in. The anchor
weighs 140 Ib.

1081. Model and photograph, of Peacock's anchor. (Scale
1 : 4.) Contributed by Capt. G. Peacock, R.N., 1861.'

N. 435.

This is a single fluke anchor, patented by Captain Peacock in 1861.
The shank is formed of two plates, between which swings a single palm
provided with toggles to insure the correct canting. At the side of
the shank are two loops which act as a stock, although arranged at the
lower end. A photograph of an actual anchor of this construction is
also shown.

1082. Model of Hunter's anchor. (Scale 1:4.) Presented
by Samuel Hunter, Esq., 1862. N. 825.

This early form of self-canting anchor was patented by Mr. Hunter
in 1862. The shank is forged with a large loop, in which can swing a bar
that connects the two arms, close to the flukes. The central portions of
the arms are halved together and secured by cotters, and in this way are
got into position within an eye formed in the lower end of the shank.
The connecting bar has its motion limited by two stops on the shank,
and it transmits the stress from the flukes. A metal stock is fitted, which
is of exceptional length.

1083. Coryton's anchor. Lent by J. Coryton, Esq., 1874.

N. 1357.

This is a small anchor introduced by Mr. Coryton in 1869. The
example, which is for use on a small boat, is constructed of cast iron,
and is also exceptional in that the arms curve in the reverse direction
to that usually adopted. The shank is in halves which, when bolted
together, grip the shackle pin and also tbe journal of the double arm
casting. Projections on the arms engage with lugs on the shackle, and
thus limit the canting of the arms to 30 deg. on either side. It is claimed
for the arrangement that it is less liable to fouling than the ordinary

1084. Model of drogue or sea anchor. (Scale 1 : 12.) Made
in the Museum from the designs of Prof. C. W. Merrifield,
F.R.S., 1869. N. 1298.

The object of a drogue is to prevent a boat or vessel from drifting when
in deep water, or to keep it head to windward. Many forms have been
constructed, frequently during an emergency, but that represented consists


of an equal armed cross, made with two spars, which extends a sail 10 ft.
square. Ropes from the four ends of the spars are connected to a hawser
about 100 ft. long. The whole is supported by a buoy which maintains it
at a depth of about 30 ft., so as to be below the moving surface water. For
a boat the anchor would be 2 ft. square.

1085. Models of Swinburne's anchors. (Scale 1 : 12.) Lent
by Capt. T. A. Swinburne, R.N., 1877. N. 1471.

These two models represent anchors patented by Captain Swinburne in
1876. The shank is a square bar upon which the arms, which are in one
forging, are slipped and secured by a through pin ; the mooring strain is,
however, taken by the solid end of the shank. The stock is a duplicate of
the arms, and can be readily removed for storage ; when turned it can be
slipped down the shank so as to stow against the ordinary arms. In the
second model the shank is twisted, so that in lowering the stock it auto-
matically turns into the plane of the arms.

1086. Models of Wasteneys Smith's anchor. (Scale 1 : 8.)
Lent by W. Wasteneys Smith, Esq., 1876. N. 1403.

This form of stockless anchor was patented by Mr. Wasteneys Smith
in 1871, and he subsequently introduced several modifications. The shank
has a cross arm fitted to it, bearing on a solid end, and secured by a cotter.
The ends of the cross arm form journals that receive the two flukes, which
are prevented from coming off again by cotters. These flukes have two
projecting toggles, which secure their canting ; being separate the flukes
are able to cant independently. The degree of canting is limited to about
42 deg. each way by stops on the flukes, which engage with the sides of the
cross arm. At the lower end of the shank is a fishing shackle, round which
the anchor will balance.

1087. Models of Martin's anchor. (Scale 1 : 10.) Lent by
C. Martin, Esq., 1874. N. 1387.

This improved form of the self-canting anchor shown in No. 840 was
patented by Messrs. C. and H. Martin in 1872. Several methods of con-
struction are described in the specification, but the model, which shows a
2- ton anchor, represents that generally adopted. The shank is formed with
a large end, which is bored out, and on one side is further recessed so as to
form two stops for a projecting lug on one side of the pair of arms.
The arm forging is in one piece, and it is threaded through the hole into
position, and there secured by a pin which drops into a recess in the bearing,
and is fixed by the pin of the fishing shackle ; the arrangement allows the
plane of the arms to swing through an angle of 42 deg. on each side. At
the upper end of the shank is secured a wide concave metal stock, which
considerably increases the holding power. A second model shows the
pieces separated.

1088. Model of Baxter's anchor. (Scale 1 : 8.) Lent by H. C.
Baxter, Esq., 1898. N. 2160.

This represents a 2 * 5-ton trunnion anchor of the pattern introduced by
Mr. Samuel Baxter in 1882. It has no stock, and is designed for being
hauled directly from the bottom into its seating, formed as an enlarged
hawse pipe in the bow of the ship, thus avoiding the labour of the usual
operations of "catting" and "fishing." When so carried, the anchor is
also ready for letting go at any moment.

The anchor consists of two steel castings, which form the flukes, and
when bolted together enclose the trunnions that project from the forged
steel shank. The flukes can swing through an angle of 45 deg. on each
side, and are provided with projections that cause the anchor to bite when
pulled horizontally, or will assist in breaking the ground when being lifted.


An adjacent photograph shows the bow of the Brazilian ironclad
" Riachuelo," of 5,700 tons displacement, the first warship fitted with these
anchors, which in this case weighed 3 3 tons each.

1089. Model of "Lenox" Royal Navy anchor. (Scale 1 : 24.)
Presented by Messrs. Brown, Lenox & Co., 1908. N. 2466.

This represents a modern form of self-canting stock anchor used by the
Admiralty, and contains improvements patented by Messrs. G. C. L. Lenox
and D. Morris in 1886 and 1891. The crown and flukes, together with the
two concave canting toggles are in one piece and form the arm casting,
which is secured to the shank by a single pin. The stock has four arms, a
modification patented in 1891. An additional grip is obtained by this
means, as the small arms or projections of the stock take the unbroken
ground between the flukes.

The model represents a 40- cwt. anchor.

1090. "Simplex" anchor. Lent by the Liquid Fuel En-
gineering Co., 1899. N. 2184.

The example shown is the smallest size self-canting or stockless anchor,
constructed under the patent granted to Messrs. H. A. House and B. B.
Symon in 1893. Such anchors are made in steel or bronze, and in sizes
weighing from 4 5 to 224 Ib.

The arms and flukes, together with the canting toggles, are first cast or
forged in one piece. This is afterwards coated with fireclay and plumbago,
and placed in a prepared mould into which the metal for the shank is
subsequently poured, so that the shank-eye is cast round the middle of the
arm. The whole anchor is afterwards annealed, to remove any cooling
stresses, and is usually finished by galvanising.

1091. Model of Byers's anchor. (Scale 1 : 12.) Presented by
Messrs. W. L. Byers & Co., 1904. N. 2357.

This anchor, patented by Mr. "W. L. Byers in 1887 and improved in
1900-3, is of the self-canting stockless class. The crown and flukes,
together with four canting toggles or tripping pieces, are in one casting
which is secured to the shank by a single shrough pin. The trips are each
made with a flat face; which, when resting on the sea bed, support the crown,
giving at the same time a downward direction to and pressure on the flukes
so as to ensure their digging into the ground when the cable tightens. The
anchor represented weighs 45 cwt.

1092. Models of Mitchell's mooring screws. (Scale 1 : 4.)
Received 1899. N. 2201.

This modification of the screw pile, patented by Alexander Mitchell in
1833, consists of a single turn of a cast-iron screw of large diam. and small
pitch, provided on its lower surface with a gimlet-point. In one example,
the screw is fitted with a shank by which it may be rotated and thus force
its way into the ground ; the top of this shank is provided with a shackle
and swivel for receiving the mooring chain. In the other example the
screw has a short stem over which fits the socket used in sinking it, but
which is afterwards removed, the mooring chain and buoy being then
attached to the short chain secured to the screw. The serrated edge shown
on these screws is a later improvement which was found to facilitate rota-
tion and entrance in stony ground. One of these mooring screws, 4 ft.
diam., weighs 11 -5 cwt. and is used with a 1'25 in. diam. cable.

1093. Model of wedge-clump mooring anchor. (Scale 1 : 24.)
Presented by Messrs. Brown, Lenox & Co., 1908. N. 2465.

The anchor represented was patented in 1901 by Mr. G. C. L. Lenox and
is a development of the earlier mooring clump previously adopted by the


Admiralty. It was first us ad in the river Orwell at Ipswich on hard smooth
ground and gave very good results even on such unfavourable anchorage.

The example shown is wedge-shaped, wider and deeper at the back than
at the front, and has a shank hinged to the inside of the clump and

Online LibraryScience Museum (Great Britain)Catalogue of the naval and marine engineering collection in the ... museum .. → online text (page 51 of 58)