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Mr. J. Buthven. The engines were of 150 nominal h.p. and drove a centri-
fugal pump, that had a horizontal fan 14 '3 ft. diam., by which water
entering through orifices in the bottom of the hull was forced out with
considerable velocity, through pipes laid fore-and-aft along the ship's sides
below the water-line. The motion was reversed by valves that controlled
the delivery, not by reversing the engines (see also No. 504).

The armament was two 6 5-ton M.L.B. guns, and the snip's complement
80 men.

Displacement, 1,190 tons; length, 162 ft.; breadth, 32 ft.; depth,
11 '3 ft. ; immersed midship section, 344 sq. ft.



STEERING ARRANGEMENTS.

Ancient vessels were steered by large oars or paddles,
passing through loops on either stern quarter and held verti-
cally. This inconvenient arrangement was in general use till
late in the 15th century and is still employed in a few countries.



344

The right-hand quarter, looking forward, being the more con-
venient, was that usually chosen by the helmsman and to this
is due the name " starboard " still, applied to that side of a
vessel.

The rudder appears to have been introduced during the
13th century, probably from China, where it still remains in a
form that closely resembles a steering paddle lashed to the
stern. It soon after reached its present form, however, for in
a seal of 1338, a rudder is represented hinged, by its forward
edge, to the stern post, as is now usual.

The lever or " tiller " fixed to the head of the rudder was for
centuries moved by hand, but as ships increased in dimensions
a compound lever was adopted, a vertical lever pivoted on the
upper deck beams being added to give more power over the
tiller ; this arrangement was generally employed till the end of
the 17th century. The application of a block and tackle to the
tiller, whence ropes or chains were led to a winch barrel turned
by a spoked wheel known as the steering wheel, dates from the
beginning of the 18th century ; it, however, remains the most
popular arrangement, and even where steam power is applied
the wheel is retained in its original form.

Numerous trains of gearing have been introduced to assist
manual power in steering, but they all reduce the speed with
which the rudder is set over, although at the same time they
prevent the rudder from overpowering the steersman. An
arrangement that has been frequently used was first patented
by John Rapson in 1834, in which the shaft of the steering
wheel is cut with right and left-handed threads into which
engage two corresponding nuts attached by links to a yoke on
the rudder head. Rapson also in 1839 brought out his " slide,"
in which the tiller is embraced by a loose block which slides in
an athwartship guide, thus preventing the slackness of the
tiller ropes that otherwise arises from their varying inclinations.
Charles, 3rd Earl Stanhope, in 1790 patented an " equipollent"
or balanced rudder in which the axis was in the centre of the
w r idth ; such a rudder would not balance, however, but by
placing the axis further forward a great reduction in the turning
effort required is now frequently effected.

The great increase in the size of ships that took place in the
last century soon led to an excessive number of seamen being
required at the helm. The desirability of utilising steam power
for this work was recognised by many, but it was not till 1867
that Mr. Macfarlane Gray introduced the first successful steam
steering gear. This was fitted to the S.S. " Great Eastern,"
and it had the " differential" valve motion by which, as in all
subsequent gears, any movement of the steering wheel admitted
steam to an engine that correspondingly drove the tiller winch,
while this engine by its motion stopped itself when the equiva-
lent movement of the rudder had been completed (see No. 1065}



345

In ships which are full at the stern, one of the most satis-
factory forms of steam steering gear in present use is Rapson's
slide (see No. 1063), but, as it occupies a considerable amount of
thwartship space, its use is confined principally to battleships.

Mr. W. H. Harfield in 1889 patented a compensating steer-
ing gear for use with steam or manual power, which is now
largely adopted. This gear is suitable for vessels with narrow
sterns (see No. 1064). The steering gear, patented by Mr. A. B.
Brown in 1888, and fitted chiefly in the Mercantile Marine, has
the engine placed on the tiller, the latter engaging with a fixed
quadrant by means of a worm wheel held between jaws at its
after end. In conjunction with this gear is fitted a device called
a " telemotor," by means of which the motion of the steering
wheel is transmitted to the engine by hydraulic pressure instead
of by shafting or bevel wheels, the fluid employed being usually
a solution of glycerine which will not readily freeze.

The application of hydraulic power to steering ships offers
many advantages over steam power, among which may be
mentioned its certainty of action, safety and simplicity. One
example of this type of gear is shown in No. 1055.

Steam steering engines are now commonly fitted in H.M.
ships in duplicate on specially stiffened vertical bulkheads in
the main engine-room in order to economise space (see
No. 1065).

The action of a rudder being due to the new direction it
gives to the stream lines passing the stern, the lines of the
afterbody have an important influence on the steering proper-
ties of a ship ; in all ordinary vessels it is found that the
quickest turning is performed with the rudder at about 35 deg.
from its mid position.

1036. Model of rudder. (Scale 1 : 24.) Presented by the
Rev. J. Hardie, 1866. N. 1139.

In this design by Mr. Blake the timbers are scarfed together and
fastened with gun-metal pins. The disposition of the braces and gudgeons
is indicated.

1037. Boat stern-post and rudder. Lent by H. Emanuel, Esq.,
1885. N. 1692.

This rudder, for attaching to row boats, was proposed by Mr. Emanuel
in 1884.

The pintle is one continuous bar and slides in a slotted gudgeon above,
which guides it on to the ordinary gudgeon below, so reducing the difficulty
usually experienced in shipping the rudder.

1038. Stern model with jury rudder. (Scale 1 : 24.) Pre-
sented by the Rev. J. Hardie, 1866. N. 1114.

This was designed by Mr. R. F. S. Blake, master shipwright in H.M.
dockyards, 1806-55, to illustrate how a vessel might be fitted with a jury
rudder in case of accident.

The rudder is made up of spars, held together by battens nailed across,
and weighted with ballast lashed to it. It is supported by a temporary
iron gudgeon held to the rudder post by ropes at the quarters.



346

1039. Models of jury rudders. (Scale 1 : 12.) Presented by
Lady Commerell, 1903. N. 2329.

As the loss of the rudder is such a serious accident to any large vessel
unless she be provided with twin screws, efforts are generally made in such
circumstances to improvise a temporary or " jury " rudder from the spare
planks, plates, cordage and other materials in the ship's store, no spare gear
for the purpose being usually carried. The models A and B, however, show
the special form of jury rudder patented in 1874-82 by Admiral Sir J.
E. Commerell, G-.C.B., Y.C., and fitted on H.M.Ss. "Fawn" in 1876,
" Cormorant " and " Wolverine " in 1881, and subsequently on some other
vessels. They were carried as part of the ship's spare equipment and could,
in case of emergency, be fitted while at sea.

In both arrangements a temporary rudder-post or spindle of metal is
substituted outside the gudgeons or braces of the original rudder-post, by
stepping its lower end into the ordinary shoe-casting, or into a special
bracket bearing attached to the lower gudgeon. The rudder-blade is then
built up by lowering, singly, a number of interlocking plates, each of which
is free to slide down a deep undercut groove or key-way in the spindle ; to
minimise the openings required in the decks for the passage of these plates,
they are lowered vertically until clear of the ship, when they turn into the
horizontal position and interlock ; they are then simultaneously fixed by
the stuffing-box in the rudder aperture. The earlier model (A) shows the
blades of .wood sheathed with metal, and each having a hinge-pin sliding in
the slot of the post ; in the later model (B) the blades are entirely of metal,
and are hinged to sliding sleeves, while a roller bearing is provided under
the rudder-head to reduce the resistance to turning.

Frequently, the most difficult work in connection with the fitting of a
jury rudder is the removal of the damaged original rudder, which is usually
held in position by a fixed plate or wooden chock bolted or riveted to the
rudder-post at or near the water-line. Model (C), however, shows the frame
of a rudder in which the locking plates slide on the spindle and are actuated
from within the ship. Each locking-plate forms part of a collar sliding
upon the spindle, which is hollow, and these collars are moved by an internal
shaft having right and left-handed threads so that the collars move oppositely
and therefore lock both ways. A relatively small movement of the locking-
plates permits of the rudder being lifted out of the lower socket and
completely removed.

1040. Model of expansible rudder. (Scale 1 : 4.) Presented
by the Rev. J. Hardie, 1866. N. 1099.

This illustrates Mr. Blake's plan for increasing the steering power of
gunboats and other shallow vessels. The bottom lower corner of an
ordinary rudder is fitted with a piece which embraces it, and which can
by a hauling rope be so turned round a pin as to increase the area of the
rudder.

1041. Model and woodcut of telescopic rudder. (Scale 1 : 2.)
Presented by Chas. Stewart, M.A., 1880. N. 1537.

This represents a proposal by Mr. Stewart for a rudder of variable area.
The rudder is in two thicknesses, and between them is a plate that can be
protruded by a chain when extra steering power is required.

1042. Model of steering arrangements for a light draught
steamer. (Scale 1 : 24.) Lent by Alex. Chaplin, Esq.,
1862. N. 890.

The features in this arrangement, patented in 1856 by Mr. Chaplin,
are that there is no keel, stem or stern post, and that steering is accom-
plished by two blades placed obliquely to the centre line at both bow
and stern in narrow vertical trunks. One of these rudders is raised



347

while the other is lowered, by bell- crank levers worked from the usual
steering wheel.

Many of these vessels were supplied to the Indian Government for the
navigation of shallow rivers.

1043. Stern model with " angulating " rudder. (Scale 1 : 48.)
Lent by Henry Lumley, Esq., 1865. N. 1043.

This shows three arrangements of the double rudders patented by Mr.
Lumley in 1862-3.

The idea is to divide the rudder into two parts, a "body" and a "tail,"
the latter being hung from the body in a similar way to that in which the
body is hung from the stern post. By a simple arrangement of links the
tail is given a greater motion than the body, so that the acting face of the
rudder becomes concave when set over, and thus more efficiently deflects
the passing water. The tail may, however, be locked to the body, thereby
converting the rudder into the ordinary form.

With this rudder the tiller at 10 deg. nearly equals the ordinary at
20 deg., while the circles described by vessels are as much as 50 per cent,
less in diameter than with the ordinary rudder.

The " Lumley " rudder was fitted to H.M. gunboat " Bullfinch " in 1862,
and subsequently to several other war- vessels as well as to ships in the
mercantile marine.

1044. Stern model with duplex rudder. (Scale 1 : 24.) Lent
by Capt the Hon. J. T. Fitzmaurice, R.N., 1865.

N. 1088.

This rudder was introduced in 4-864 by Capt. Fitzmaurice, when com-
mander of H.M. training brig " Sealark."

It consists of two triangular plates, connected along one edge and stayed
apart at an angle of 33 deg. This wedge gives greater effect than a flat
rudder for a moderate movement of the tiller, but at the cost of additional
resistance when not steering.

1045. Stern model with twin rudders. (Scale 1 : 16.) Lent
by Capt. T. B. Heathorn, R.A., 1879. N. 1523.

This illustrates Capt. Heathom's double-rudder and speed-checking
device, patented in 1879.

The vessel is provided with two stern posts and rudders, leaving space
for the screw to work between. The tillers consist of bell-crank levers,
the outer arms of which are connected by the usual ropes to a steering
wheel, while the two inner arms are slotted and have a pin travelling in
them, by which means they are so connected as to secure their acting in
unison.

There is, however, a second wheel further aft, which when operated
moves the travelling pin, by screw gear, and causes the two rudders to
turn outwards through about 45 deg., in which position they act as brakes
in arresting the motion of the vessel without exerting any turning action.

1046. Stern models with balanced rudders. (Scales 1 : 24
and 1 : 48.) Presented by J. Scott Tucker, Esq., 1865.

N. 1059-60.

These show the rudder proposed by Mr. Tucker in 1864. The gudgeons
project considerably from the stern post and support the rudder nearer its
centre, so that the resistance of the water has no turning action on the
rudder. Slots in the rudder, underneath the gudgeons, permit it to be
lifted and unshipped.



348

1047. Stern model with twin screws and balanced rudder.
(Scale 1 : 48.) Lent by Prof. C. W. Merrifield, F.R.S.,



1869. N. 129



This shows an arrangement of twin screws proposed by Prof. Merrifield ;
two Griffiths' screws are employed, but the stem does not extend between
them, as now usual. The rudder is of the balanced type and is arranged
in the centre line of the ship ; it depends for support entirely upon its
head, which is accordingly of unusual strength ; the weight is carried by
friction rollers.

H.M.S. " Penelope " (1868) had an arrangement of stern somewhat
similar to this.

1048. Model of Lawson's bracket rudder. (Scale 1 : 4.)
Lent by Messrs. Bates, Austin & Co., 1905. N. 2377.

This arrangement for facilitating the repair or renewal of bushes and
bearings to ships' rudders was patented by Mr. "W. B. Lawson, in 1895,
and has been adopted by many important shipping companies.

It consists essentially in carrying the weight of the ordinary rudder
upon one or more special " bearing brackets " placed between the usual
gudgeons and braces ; the latter take no vertical bearing whatever, but are
fitted with pintles for steadying only ; the pintles and bushes are rendered
capable of easy inspection or removal. The bearing brackets are forged or
otherwise attached to the stern post and rudder, preferably at positions
above the light load line of the vessel, and their working faces are slightly
recessed for hardened steel bearing plates or friction discs 1 * 25 in. thick ;
by slightly lifting the rudder these may be readily taken out and renewed
when necessary. The pintles, instead of being fitted as usual on the rudder
braces with their points downwards, are here inverted and seated in the
gudgeons on the stern post and lignum-Vitse bushes are fitted to the rudder
braces. These bushes, formed of eight separate staves, are put in place
from above, and a tapered metal key driven in to complete the circle ; the
whole is then finally held in place by a metal collar which is tap -bolted to
the upper part of the brace. To rebush the pintles no unshipping or
lifting of the rudder is necessary ; by removing the collar and then with-
drawing the key by means of a stud-bolt, as shown, the whole of the
staves may be taken out and replaced.

Full size models of a bearing plate and of the bushing arrangements
are shown, and also a scale drawing with sectional details of the same.



1049. Telescopic tiller. Lent by Henry Emanuel, Esq., 1885.

N. 1694.

This is a tiller for small sailing or row boats ; it can be lengthened at will
by drawing out the metal tubes of which it is composed.

1050. Model of steering gear. (Scale 1 : 12.) Presented by the
Admiralty, 1864. N. 1003.

This modification of the tiller gear was proposed in 1861. The tiller
rope is led through double blocks as usual, but on the tiller is an adjust-
able double block, for which possibly a position may be determined that
reduces the slight alterations ordinarily found in the length of the tiller
rope.

1051. Model of hand-steering gear. (Scale 1 : 3.) Received
1903. N. 2320.

The use, as a tiller, of a geared quadrant driven by spur gearing from
either a vertical or a horizontal steering wheel was patented in England as far
back as 1779. Since then various forms of such mechanism have been



349

invented and largely used in both hand and steam gears for the steering
of ships ; the modification shown, however, is that patented in 1862 by
Mr. D. L. Allen.

A quadrant-shaped toothed segment attached to the rudder-head is the
tiller, to which the movements to port or starboard are transmitted by a
pinion gearing into the toothed rim of the quadrant and driven by a vertical
shaft connected by bevel wheels to the horizontal shaft of the usual steering
wheel. Extra depth is given to the face of the pinion to allow of the rise
and fall of the rudder-head in a seaway.

1052. Stern model with, steering gear. (Scale 1 : 12.) Pre-
sented by the Admiralty, 1864. N. 1002.

This illustrates Admiral Martin's steering arrangements for a vessel
with a well for raising the screw, as fitted in several of H.M. ships about
1858.

The tiller, which is worked by a wheel in the usual manner, is fixed
to a false rudder-post on the starboard side of the trunk, and the true
rudder-post is connected to it by double arms on each post and side rods.

1053. Model of steering wheel. (Scale 1 : 8.) Lent by
Andrew Murray, Esq., C.B., 1867. N. 1166.

This is known as the " Niagara " wheel, from its having been fitted in
1857 to the U.S. corvette " Niagara." It was designed by Mr. Murray when
chief engineer at Portsmouth Dockyard.

The wheel is placed directly over the axis of the rudder, whose weight
is taken by a collar resting on six friction rollers. The top of the rudder
post is hooped by a ring, with two lugs on it, each embracing a pin
attached to a separate half-nut sliding between guides on a square
double -threaded screw, cut both right and left-handed, so that only
diamond- shaped pieces are left as threads. One nut is right-handed
and the other left, so that when the wheel is moved the nuts travel in
opposite directions and turn the rudder by a couple of nearly balanced
forces.

1054. Stern model with screw steering gear. (Scale 1:4.)
Presented by Messrs. R. Napier and Sons, 1867. N. 1169.

This represents the steering arrangement fitted by the donors to the
mail S.S. " Yille de Paris," " Periere," (see Nos. 236), and many other ocean
steamers.

The foremost steering wheel has an ordinary chain pulley, loose on
its shaft, but which can be secured to it by a clutch ; from this pulley a
chain leads to a double block and tackle at the tiller in the usual way.

In rough weather this arrangement is discarded, and both wheels are
used to work the more complex and powerful gear. This consists of a
steering shaft, screwed with a single right-handed square thread screw for
half its length, while the other half is left-handed. On each of these
threads is a long nut sliding on parallel guide-rods and connected by links
to a double-armed lever on the head of the rudder-post. Both screws tend
to turn the rudder in the same direction by balanced forces, as in Murray's
arrangement (see No. 1053).

1055. Model of hydraulic steering gear. (Scale about 1 : 24.)
Received 1907. N. 2449.

The apparatus shown was patented in 1877 by Messrs. A. Lafargue and
C. Martin and was adopted on the Thames, repeated failures of steam
steering gears about this time having brought the subject into notice.

On the deck of the vessel is fixed a cylinder, to the piston of which is
attached a trunk or hollow piston rod and to the rod a crosshead working
in fixed guides. Securely fastened to the rudder-head is a helically grooved
collar, in the grooves of which work friction rollers attached to the cross -
head so that the elevation or depression of the crosshead and trunk



350

produces a circular motion in the rudder. Rotation of the piston and
crosshead is prevented by the guides. The under side of the piston is
always open to an accumulator, the water in which is at constant pressure,
whilst the upper side can be put into communication with the pressure or
exhaust by means of a slide valve controlled by the steering wheel. As
the area of the upper side of the piston is considerably greater than that
of the under side, the admission of water under pressure to the former
causes a downward movement of the piston. When the upper side is in
connection with the exhaust there is an upward movement and a contrary
motion on the rudder. To indicate the angle of the rudder at the steering
platform, a chain passes in opposite directions round a quadrant fixed to
the rudder-head, and thence round a quadrant 011 a hollow vertical rod,
which has a lever at its lower end and communicates with the indicator at
its upper end. The lever is connected with a crank on the valve spindle and
this arrangement acts as an automatic cut-off to the slide valve. The gear
is controlled by means of a second crank attached to the valve spindle,
operated by the steering wheel through an inner vertical rod.

In case the rudder should be struck by a heavy sea, a cylinder relief valve
is provided which opens inward and allows the water to flow back into the
accumulator. The hand pump shown is for raising pressure in the accumu-
lator. It is stated that the amount of water required is so small that about
5 gal. will suffice to work a vessel of from 1,000 to 5,000 tons.

1056. Archer's steering gear. Lent by the Dunstan Engine
Works Co., 1883. N. 1591.

This is a neat and compact application of epicyclic gearing, patented by
Mr. Thomas Archer in 1882 by which the motion from the hand- wheel to
the sprocket-wheel of the tiller-chains is so reduced as to give sufficient
power, while at the same time the gear is self -holding.

To the shaft of the steering-wheel is secured an eccentric, on which runs
loosely a spur-wheel of 27 teeth ; this wheel has an arm extending from it
which passes down the supporting column and is steadied by a fixed pin at
the lower end. The chain wheel runs loose on the shaft, but on its side has
an internally geared spur-ring, containing 30 teeth, which is driven by the
teeth of the wheel on the eccentric shaft, the result being that 10 turns of
the hand-wheel are made to one turn of the tiller-chain wheel.

1057. Model of hydrostatic steering gear. (Scale 1 : 16.)
Lent by Admiral E. A. Inglefield, R.N, C.B., F.R.S., 1871.

N. 1331.

This apparatus was fitted in 1869 to H.M.S. " Achilles," a battleship of
6,121 tons displacement launched in 1863. At that period sails were much
used by warships, so that although steam had been successfully applied to
steering, it was considered that such power would not be at all times
available ; to overcome this difficulty Admiral Inglefield invented the gear
shown, in which water entering the ship supplies the motive power, and the
floating vessel becomes a form of hydraulic accumulator.

The pressure due to the difference in level of the water in the bilge and
that outside (about 8 Ib. per sq. in.) moves a large piston, the rod of which
extends in both directions so as to form rams that give a hydraulic pressure
of 600 Ib. per sq. in. This pressure-water is conveyed to two hydraulic
cylinders connected to a Bapson's slide actuating the tiller. The used
water, that is necessarily discharged into the bilge, is removed at intervals by
the ordinary pumping arrangements of the vessel.

1058. Steering gear. Lent by D. S. Porteous, Esq., 1890.

N. 1839.

This alternatively hand or steam gear was patented by Mr. D. W.
Porteous in 1886, and embodies a winch mechanism patented by him in

1884-5.



351

When used as a manual gear, the effort exerted on the steering wheel is
transmitted by spur gearing to a lower shaft on which is an eccentric.
Running loose on this eccentric is a double spur ring, which gears into an
internally toothed ring secured to one of the standards of the machine, and
also with an internally toothed ring formed in the boss of the sprocket
wheel that controls the tiller chain ; the gearing and this epicyclic train
causes the tiller chain drum to revolve at one-tenth of the speed of the



Online LibraryScience Museum (Great Britain)Catalogue of the naval and marine engineering collection in the ... museum .. → online text (page 49 of 58)