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working through a slot in the front of the anchor, which allows the shank
to rise and fall through a limited angle. This construction prevents the
anchor from turning over on its back, as sometimes happened in former
mooring anchors, any such tendency being arrested by the upper part of the
slot coming in contact with the shank. The liability to skid is similarly
prevented by the lower part of the slot. In very rugged ground, a stock is
sometimes added to a prolonged shank, as in such ground a tendency to turn
over sideways has been observed.

It is stated that the holding power of these mooring anchors has been
found to be at least three times that of some other forms. They are made
in various sizes, weighing from 1 to 12 tons.

1094. Model of anchor and cat-head. (Scale 1 : 12.) Pre-
sented by the Rev. J. Hardie, 1866. N. 1106.

This shows the arrangement introduced by Mr. R. F. S. Blake for so
carrying an anchor that it can be readily released ; it very closely resembles
the arrangement still generally used. The shackle end of the anchor is
supported by a rope that passes over horns on the sides of a projecting
beam known as the "cat-head," while the arms of the anchor rest on
a sloping shelf, known as the "bill-board," on which they are retained
by another rope. The ends of these ropes are secured by two levers, which
are retained in position by two hand-levers, so that when the two hand-
levers are pulled both ropes are released, and the anchor descends without
any constraint in running out beyond that offered by the mooring cable.

1095. Model of anchor and cat-head. (Scale 1 : 12.) Made by
the Admiralty, 1886. N. 1780.

This model shows the arrangement generally in use in H.M. Navy for
carrying the bower anchors ; it also shows the standard Admiralty anchor
of 4 tons. The bill-board is similar to that of the earlier form, but is con-
siderably smaller, while the chain by which the lower end of the anchor is
secured is retained by a somewhat more compact arrangement of Blake's
releasing levers. The " cat-head " is in the form of an iron davit, on the
top of which is a similar releasing gear with a curved lever that extends to
the bulwarks.

In getting the anchor up, the cable is continuously wound in until the
ship is over it ; the anchor then usually leaves its bed easily, and it is raised
until above the water level. The small catting chain that is tied to the links
of the cable for some distance is thus brought within reach, so that it can be
passed through a block on the cat-head. By this chain the anchor can now
be lifted higher, so that the fluke end can be hauled on to the bill-board by
the " fishing " chain ; this is provided with a la,rge open hook by which the
anchor is readily caught.

1096. Model showing method of carrying sheet and spare
anchors. (Scale 1 : 16.) Presented by Sir 0. Gage Brown,
K.C.M.G., M.D., 1894. N. 2027.

The sheet anchor is the largest anchor carried, and owing to the limited
space available is arranged abaft the fore rigging. In this position, however,
some difficulty was experienced in lowering it clear of the ship until the
arrangement shown, which was invented in 1842, by Capt. C. Brown, R.N.,
of Portsmouth Dockyard, was introduced, and which has since been
universally adopted.

As shown in the model, the anchor is supported with its shank in a
horizontal position, by two jaws earned by inclined rods which are hinged
at their lower ends to the vessel's side. The anchor and these crutches



366

are ptilled toward the ship's side by two chains, retained by a trip gear
by which both are simultaneously released : when' this takes place the
crutches, in lowering, throw the anchor from the ship's side before the
shank leaves them. As the sheet anchor is but seldom used, temporary
lashings are added by which the risk of accidental releasing is avoided.



1097. Chain cable and accessories. Lent by Messrs. Brown,
Lenox & Co., 1892. N. 2003.

These are examples of the iron cable used for mooring, anchoring, or
rigging purposes, together with the usual gear for manipulating, joining
together, and temporarily securing the same.

Cables made of separate welded iron links were successfully introduced
by Capt. Sir S. Brown, R.N., about 1812, and have now universally super-
seded those made of twisted cotton, hemp, or jute. The " stud-link "
chain, formed by placing a cross bar or strut between opposite sides of
each link, is the most approved pattern, being 10 per cent, lighter than the
equivalent unstudded or close link type, without being any more liable to
form that peculiar twist known as a " kink," which so reduces the strength
of any chain or rope.

Mooring cables, secured by heavy anchors and sinkers, are placed at the
bottom of harbours or roadsteads to form a permanent attachment for the
buoys provided for vessels when ordinary anchorage is impracticable or
undesirable.

Ships' cables, by which vessels are held at anchor, are usually made up
of a number of lengths of chain of 12 5 fathoms each, connected together
by " joining shackles " and to the anchor by an " anchor shackle." For
convenience in making these connections the end links of each length are
made without studs, but of increased diameter, to give equality of strength.
Temporary attachments to cables are made by means of " slips," which also
give facilities for readily disengaging.

(a) Examples of 2'6 in. and 3 in. mooring cable, and joining shackles for
mooring cable.

(b) Single link of Admiralty pattern 4 in. mooring cable, square section.

(c) Piece of the largest size, 2 5 in., ship's cable.

(d) Example of 1 in. ship's cable, showing a flush pin in the shackle, to
obviate fouling when passing through a hawse pipe.

(e) Permanent swivel as fitted to mooring buoys for the use of ships.

(f) Mooring swivel for attaching to ship's cables, to permit vessel to
turn freely when riding with both anchors out.

(g) Chain swivel, fitted at each end of a ship's cable, and at intermediate
positions if necessary, for taking out " twist " in the chain.

(h) Chain with cable slip attached.

(fc) Deck stopper chain, with shackle for securing to stopper bolt and slip
for temporarily attaching to cable.

(I) " Clear-hawse " chain, for supporting the weight of cable outside of
the hawse pipe ; this shows a roller shackle through which a rope may be
rove, and a slip for attaching to cable.

An adjoining case contains other details of cable fittings and manu-
facture, together with tools, etc., used in the manipulation of chain cable.

1098. Chain cable. Presented by Messrs. Brown, Lenox & Co.,
1906. N. 2426.

This is a tested sample of the cable manufactured by Messrs. Brown,
Lenox & Co., for the quadruple- screw turbine steamer " Mauretania," a vessel
of about 33,000 tons gross, built in 1906 for the Cunard Company by Messrs.
Swan, Hunter and Wigham Richardson, Ltd.



367

The cable is the largest ever made for ships' use ; its links are of iron,
3 -75 in. diam. Each link is 22 -5 in. long and 13 '5 in. wide, and, with its
cast steel stud, weighs 170 Ib. The three links shown were tested at Lloyd's
Proving House, Cardiff, and withstood a load of 350 tons without showing
signs of fracture, although they were elongated six inches.

The total length of the cable for the steamer is 1,900 ft., and weighs,
with the connecting shackles, about 130 tons.

1099. Joints for cable links. Lent by C. Martin, Esq., 1874.

N. 1338.

These two models show : (a) a forged link with its joint made by the
usual scarf weld ; (fc) a link in which the joint is made with a stepped scarf,
patented by Mr. Martin in 1872.



1100. Models of cable compressors. (Scale 1:8.) Presented
by the Admiralty, 1864. N. 1001.

This compressor, of Admiralty pattern, is still used in both wooden and
iron ships for checking the chain cable when running out round the riding -
bitts after an anchor has been let gOj The arrangement was invented by
Capt. Chesman, when iron cables first came into general use about 1830,
and subsequently improved.

The compressor, which is placed on the under side of the anchor deck,
consists of a curved iron lever pivoted on a bolt at one end, and fitted at the
other end with a tackle by which it can be caused to press the cable against
the side of the chain pipe, thus causing considerable frictional resistance.

1101. Model of cable compressor. (Scale 1 : 12.) Presented
by William Batten, Esq., 1858. N. 168.

This modification of the Admiralty compressor was patented by Mr.
Batten in 1831. Greater closing pressure is obtained by the use of a com-
bined lever and cam motion, while a stop is added which limits the travel.

1102. Model of cable compressor. (Scale 1 : 4.) Presented
by the Rev. J. M. Kilner, 1878. N. 1506.

This breaking arrangement was patented by Mr. Kilner in 1871. It is
in the form of a shackle which is fixed to a casting secured to the deck ; the
bow of the shackle is extended in the form of a lever by which it can be
forced down upon the chain cable.

1103. Model of riding-bitt and compressor. (Scale 1 : 12.)
Made by the Admiralty, 1887. N. 1779.

When lowering the anchor, the outgoing cable from the hold or locker
passes upwards, through a deck-pipe fitted with a securing device called
a " compressor," to the sprocket wheel of a winch or capstan ; it then
passes round a large fixed post or bollard, called a " riding-bitt," and over
another securing device known as a " bow-stopper." When the anchor
has reached the bottom and sufficient cable has been payed out, the cable
is temporarily secured by a short chain called a " deck- stopper," while the
inner end is taken one additional turn round the " riding-bitt," so as to
obtain greater security while the ship remains at anchor ; during this
operation the weight of the hanging chain in the locker is carried by the
adjacent compressor.

The model shows the riding-bitt of H.M.S. "Inflexible" (1876). The
bitt is a hollow casting of iron or steel, secured to the anchor deck by a
flange which receives bolts that pass up through a massive timber base built



368

between the deck beams. To resist the severe local stresses on the deck,
additional pillars are here fitted, while a strong central web extending to
the deck below is also added. There is on one side of the bitt a nipping
lever or compressor for temporarily holding the cable, but this part of the
arrangement is not followed in later ships.

1104. Models of cable stoppers. (Scales 1 : 4 and 1 : 3.) Pre-
sented by Messrs. Bullivant & Co., 1902. N. 2285.

A cable stopper, or "compressor," for holding a wire rope at any point
was patented in 1874 by Mr. W. M. Bullivant, when this class of rope was
coming into nautical use and the importance of securely holding it without
injuring it was realised. It consisted simply of a long trough fixed to the
deck and provided with a semicircular groove fitting the rope, while a
similarly shaped block could be pressed into the trough by a screw ; in this
way the frictional grip from a great total pressure was obtained, while,
owing to the length of rope over which this was distributed, no injury was
done to its material or structure.

The form of compressor, patented by Mr. Bullivant in 1874, is illustrated
by the first two models shown, in which, to facilitate the insertion of the
cable, one side of the trough is open ; the closing block is mounted upon an
eccentric formed on the back of a worm wheel moved by a worm or hand
wheel by which the pressure was applied and maintained. At first the
block had side guides, but the model shows how, by the use of two pins
engaging in annular slots of the same throw as the eccentrics, these were
dispensed with. In another example of this arrangement, two pressers
were employed as shown, and the trough groove had a crest or undulation
in it which added to the grip by slightly bending the rope.

In 1880 Mr. Bullivant patented two forms of compressor in which the
pull on the rope tended to increase the grip, so that they became " automatic
grippers," and these are the arrangements shown, to a scale of 1:3, in the
two largest models. In one of these there are three shrouded toothed wheels,
mounted eccentrically, and engaging with a shrouded rack formed on the
under surface of a block which can be moved endways by another toothed
wheel on a horizontal shaft arranged for taking capstan bars. When the
rack is moved endways its teeth cause the eccentrics to revolve, so that
they raise it and cause it to grip the rope between itself and the fixed
framing, which, in the model, has been partly cut away to render the
mechanism visible.

In the other automatic nipper, which is arranged horizontally and
represents the later construction, there are seven inclined struts, or toggles,
one end of each of which is notched into the framing and the other into
the block, while there are a pair of pinned links which retain the movable
block in position. The block is moved endways by a screw, fixed to it and
traversing a nut fitted with a wheel, by which it can be turned, and carried
in a spherical bearing which gives the necessary freedom. When the screw
is forced inwards it pushes the block which, by the toggles, is thus caused
to grip the rope between itself and the framing ; the attachment of the
screw to the block is by a pin in a slotted hole, so that the pull of the rope
can automatically increase the grip without the screw being moved.

1105. Model of cable slip hook. (Scale 1 : 6.) Presented by
the Rev. J. Hardie, 1866. N. 1115.

This is a cable holder introduced by Mr. R. F. S. Blake into the Royal
Navy. The hook, which is attached to a chain secured by a shackle to the
deck, is in two portions, hinged together and locked by an enclosing link.
By knocking back the link everything is freed.



369

LOGS AND CLINOMETERS.

Many instruments used in nautical work will be found in
the collection of scientific apparatus shown in the Western
Galleries of the Museum, but those of specially marine
application are retained in this collection.

For measuring the speed of a vessel some form of "log""
is usually employed at intervals, although for determining the
position of the ship astronomical observations are the only
reliable means when land is invisible. The old-fashioned log-
consists of a teak float to which a light rope is attached ;;
the float is thrown overboard and the line allowed to run
freely from a reel so that the float remains nearly stationary^
In this way the number of knots on the rope that run out in
a certain interval of time, as determined by a sand glass,
indicates the speed of the ship ; when this interval has elapsed
the line is stopped and hauled in again for future use. A trip*
arrangement on the log causes it to turn edgeways, and so*
reduce its resistance when being recovered.

Another means of measuring the velocity of a ship through
the water depends upon the alteration in the pressure in a tube-
projecting through the bottom, as the speed varies, but this-
plan has never been extensively adopted.

The modern logs, however, do not attempt to give the*
speed, but the distance travelled, which is the important factor
when sailing by " dead reckoning." Such a log consists of"
an elongated float provided with inclined vanes and connected!
by a plaited rope with a counting apparatus on deck. The-
float as it is dragged through the water rotates with a<.
velocity that is proportional to the speed of the vessel, and
the dial is graduated by experiment in such a way that it
indicates the distance travelled in nautical miles. These
instruments give reliable readings, but as they also register
motion due to currents, etc., they may fail to indicate the true-
position of the vessel, particularly if there has been any
considerable lateral drift.

For determining the angle of rolling, or even the list of sa
vessel, an observation upon the horizon gives the most accurate
results, but is not always practicable or convenient, so that
some form of pendulum or spirit level is generally resorted
to. In these instruments arrangements are made to check or
damp out oscillations, but all such gravity apparatus give
results that are influenced by the motions of the vessel for
the same reason that the surface of the water in the buckets-
of an overshot water-wheel does not remain level when the
wheel revolves.

1106. Perpetual log. Presented by J. Taylor, Esq., 1857..

N. 3.

This log, for measuring the [distance travelled by a ship, was patented
by William Foxon in 1772, and one was supplied to H.M.S. " Enterprise ? "
in 1775.

TJ 0773. A A



370

It consists of two parts, a spiral log of sufficient weight to be just
buoyant and the recording mechanism shown. The spiral log is towed after
the ship by a line long enough to keep it out of eddy currents, and is con-
nected with a train of toothed wheels in a case fixed on the taffrail. The
train revolves at a speed proportional to that of the ship. An endless
screw receives the motion, its arbor carrying a flywheel. Two dials are
provided : one, with a single hand for frequent readings, shows small
distances ; the other has a large hand which revolves once for 100 revs, of
the single hand, so that this dial will record 3,000 times the distance of the
other. The log will register up to 18,000 knots.

1107. Propeller log. Presented by E. Massey, Esq., 1879.

N. 2415.

In this log both the register and rotator, connected by a short rope line,
are placed in the sea. In the original form, patented by Edward Massey in
1802, this connection was made by four lengths of cane rod, each about
17 in. long, joined together by a short length of chain. This arrangement
avoided the friction of turning the long length of rope which would have
been necessary had the registering gear been on board. The rotator is of
the blunt-ended kind with four vanes ; the register is an ordinary counter,
the first wheel of which is set in motion by an endless screw on the shaft
joined to the connecting rope. A universal joint is used to form the
connection between the worm- shaft and the rope : in later forms of this log
this joint is protected from the fouling action of weeds, etc., but here it is
exposed. The whole of the wheelwork and dials are cased in brass ; pro-
jecting side wings are also screwed on to prevent the register from rotating.
The index is protected by a brass cap. Portions of a mile can be read off
and distances up to 100 miles are recorded.

1108. Logs. Presented by A. Tolliausen, Esq., 1858. N. 60.

These logs were patented by Mr. A. Pecoul in 1854, and were intended
both for measuring the distance travelled by the ship and for sounding
without heaving-to. The smaller example appears to have been intended
for measuring distance only, but the larger one has additional fittings for
taking soundings. The log is of a conoidal shape, with the vertex pointing
downwards, being kept in that position by a suitable weight attached to the
end of the line. At a certain distance from the log, the line carries a cork ;
two ropes, attached to apices of the log, end in a pin (shown in the smaller
example) which is inserted in this cork. There are thus three points of
attachment of the metal log to the log line. The speed is determined by
observing how much line runs off from a reel on the ship in a given time.
When the record is taken, a check on the log line immediately withdraws
the ping from the cork, the log assumes a horizontal position, and can then
be hauled aboard easily.

1109. Harpoon log. Received 1906. N. 2425.

This propeller log, patented by Mr. T. "Walker in 1861, has a blunt end
with four vanes. In the details of its mechanism it resembles No. 1111, but
the general arrangement is different. In this example the registering gear
is directly attached to the log line and to prevent rotation a large harpoon-
shaped fin of brass is fastened to the back of the body. The propeller end
of the log is connected with the register by a collar, fastened by screws,
which is prolonged to form a bearing for the shaft operating the registering
gear. This shaft is fixed in the inner end of the rotating log. The end of
the connecting collar forms one face for friction rollers working in the same
way as in No. 1111, only in this log the shaft and attached pointer rotate
and drive the wheel train through the carrier on the worm- shaft. Portions
of a mile may be read off the indicator, and distances up to 100 miles
are recorded.



371

1110. Dial log. Presented by Admiral F. Bullock, R.N.,
1865. N. 998.

This log, for measuring the speed of ships, was patented in 1863 by
Admiral Bullock.

The use of the instrument depends on the varying resistance to towing,
at different speeds of the ship, of a float which is dragged through the
water astern. The float, a metal cylinder closed at the ends, is about 12 in.
long by 1-5 in. diam., and is attached to the recording indicator by a log
line about 50 ft. long. A collar, to which is attached a pulley block, slides
n a vertical rod fastened to the stern of the ship. The log line passes
round the block, and can be thus regulated to give a suitable direction for
towing the float. It is arranged that the portion of the line attached to
the float is nearly horizontal, the sliding collar on the rod being only about
4 ft. above the surface of the water. The indicator, which is fixed within
the ship, is an ordinary spring balance, and weighs the stress on the log
line. It is graduated from a standard instrument which has been
experimentally tested at known speeds. Only the indicator is exhibited.

1111. Propeller log. Presented by E. Massey, Esq., 1879.

N. 2416.

This log was patented by Mr. J. E. Massey in 1865. By means of a
f our-bladed screw and worm gearing, contained within the body, a registering
counter is actuated. The tube with its vanes, train of wheels, and indexes
is caused to revolve round a stationary gun-metal worm-shaft geared into
the first wheel of the train. The inner end of the log ends in a truncated
cone through which this shaft passes ; an outer cone, to which is attached
a ring and thimble for turning the instrument, is fastened to the shaft.
This outer cone does not touch the log, but acts as a protector against
weeds, sand, etc. The inner cone, which is fixed to the instrument, is free
to revolve on the shaft, and contains friction rollers working between two
discs inside the cone, one fixed to the cone and the other screwed on
the shaft. There are three rollers free to revolve, attached by screws to the
faces of a triangular block fitting loosely on the shaft. By this means l|ie
friction and wear produced by the strain of the log dragging through the
water are reduced to a minimum. The gun-metal shaft is held stationary
by the attached log line, and is in contact by means of a pointer at its end
with a earlier actuating the worm. The reading is taken by hauling the
log on board and exposing the index by rotating the protecting sleeve.
The index records fractions of a mile, and will read up to 100 miles.

1112. Self-registering ship's log. Presented by B. T. Moore,
Esq., 1882. N. 1578.

This fan log was patented by Mr. Moore in 1873.

From the tail of the elongated body projects a four-bladed screw, which
by means of worm gearing, rotates a counter contained within the body
and registering from 0'25 of a knot to 100 knots. The reading is taken by
hauling the log on board and holding it vertically. The index is protected
by a sleeve.

1113. Deck log and speed gauge. Presented by E. Massey,
Esq., 1879. N. 2417.

In this log the recording mechanism is kept distinct from the rotator,
and in that respect it differs from others by the same inventor. It was
patented in 1876 by Mr. J. E. Massey. The rotator is of the usual four-
bladed kind with blunt end. It is connected with the recording mechanism
by a cable-laid log line sufficiently long to keep the log out of eddy currents.
Brackets are securely fastened to the top and side of the bulwark near the
stem, one on each side of the ship. A stand arm, connected with the
registering gear and dial by a swinging joint, can then be easily slid into a

A A 2



372

groove in the fixed bracket. In this position the recording mechanism is
firmly held, but is free to turn in order to adjust itself to alterations in the
ship's course.

The registering mechanism attached to the ship's quarter consists of a
train of wheels with a graduated dial. Attached to the case of the dial is a
cylinder containing a shaft or arbor ending in a circular face plate which
operates the last wheel of the train by means of a pointer attached to its



Online LibraryScience Museum (Great Britain)Catalogue of the naval and marine engineering collection in the ... museum .. → online text (page 52 of 58)