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The first experiment made with Ericsson's propeller was conducted in
1837, when the " Francis B. Ogden " was built and fitted. She was 45 ft.



329

long, 8 ft. beam, 2 -25 ft. deep, and had a high pressure engine with two
cylinders 12 in. diam. by 14 in. stroke, making 30 revs, per min. with a
boiler pressure of 50 Ib. She towed a ship of 630 tons burden at a speed of
4 5 knots, against the tide.

The second experiment was the " Robert F. Stockton," built by Messrs.
Laird Bros, in 1838. She was 63 -4 ft. long, 10 ft. beam, 7 ft. deep, 33 tons
register, and 30 h.p. ; she attained a speed of 13 knots on the Thames with
the tide. She afterwards crossed the Atlantic under canvas, and worked for
many years as a New York tug, under the name of the " New Jersey." A
lithograph of this vessel is shown adjacent.

By the end of 1842, thirteen river steamers with Ericsson's propeller
were in use in America, and in 1844 H.M.S. " Amphion " was fitted with this
means of propulsion.

977. Model of propeller. (Scale 1 : 12.) Presented by
Messrs. Bullivant & Co., 1902. N. 1894.

This appears to represent the central blades of one of Ericsson's duplex
propellers of 1836 (see No. 976). The piece is therefore much more like a
modern propeller than was the complete arrangement.

978. Experimental whole inodel of a screw ship. Presented
by Mrs. H. Vansittart, 1874. N. 1365.

This was constructed by James Lowe between 1834 and 1838, the date
of his patent, to test the merits of his screw propeller. It is fitted with a
spring-driven clock-train that works a four-bladed propeller, about one-
eighth of a turn in length.

Lowe had been apprenticed to, and was subsequently in partnership with,
Edward Shorter (see No. 966), and so had his attention turned to screw
propulsion. He was assisted financially by several gentlemen, who, in 1837,
purchased the barge " Wizard," afterwards named the " Cycloid," a vessel
of 25 tons burden, 50 ft. long, and 8 ft. beam. She was fitted with 12 h.p.
engines, and experiments were tried with one, two, three, and four blades,
set at angles vaiying from 22 to 42 deg. The boiler was only of 7*5 h.p.,
but a speed of 6 knots was attained.

In 1843 an action was commenced with the object of invalidating the
several patents relating to screw propulsion then in force ; after seven years'
litigation it ended in each side paying its own costs. The following patents
were assailed B. Woodcroft (1832), F. P. Smith (1836), J. Ericsson (1836),
J. Lowe (1838), and G-. Blaxland (1840) ; the owners combined to defend.
In the first three cases extensions of six, five, and five years respectively
were ultimately granted ; the others were not extended.

979. Stern model with Lowe's propeller. (Scale 1 : 24.)
Contributed by Messrs. Jackson and Watkins, 1861.

N. 430.

This propeller, patented by James Lowe in 1838, is equivalent to a pair
of two-bladed screws superposed on a single shaft ; the blades are shaped
like pruning knives and are riveted to the boss.

980. Drawings of Lowe's propellers. Presented by Mrs. H.
Vansittart, 1874. N. 1370.

(a) The first engraving shows the various forms patented by James Lowe
in 1838 (see also No. 978).

(fc) This is a specification drawing from Lowe and Wyche's patent of
1852. It shows two- and four-biaded screws on an oval boss and cast solid
therewith. (A model of this is also shown, N. 1367.)

(c) This is from Lowe's patent of 1855 ; the blades are divided into two
or more parts and placed in sets in a line inclined to the axis of the boss at
30 deg. The object of the arrangement was to avoid the total loss of a



330

blade should any solid obstruction be encountered. The screw was first
tried in 1857 on H.M.S. " Bullfinch."

(d) This is Lowe and Harris's patent of 1862. In this screw any circular
section of a blade is a sinuous curve, and the surface is one of varying pitch
(see also No. 1001).

981. Model of " conoidal " propeller. (Scale 1 : 8.) Pre-
sented by George Rennie, Esq., 1857. N. 143.

This propeller was patented by Mr. Rennie in 1839. It is three-bladed,
and the surface of the blades is " obtained by the descent of a tracer down
the surface of a cone or conoid " ; the blade so constructed has increasing
pitch, and is shown tapering in width from the centre to the tips.

982. Model and drawing of "conoidal" propeller. (Scales
1 : 8 and 1 : 16.) Presented by J. K. Rennie, Esq., 1876.

N. 1416-7.

The model shows an improved form of No. 981, obtained by cutting
away the inefficient portion of the blade near the centre. It was in this
form, as seen by the drawing, that the screw was fitted in 1842 to the
" Mermaid," afterwards H.M.S. " Dwarf." The engine had two vertical
cylinders, 40 in. diam. by 32 in. stroke, and made 36 revs, per min. ; it
drove the propeller shaft through two sets of multiplying spur gear. In
March, 1843, the " Mermaid " attained the then exceptional speed of
upwards of 11 knots.

The drawing shows also the outer bearing for the screw-shaft and a
claw coupling for disconnecting.

983. Propeller of H.M.S. "Rattler." Contributed by the
Admiralty, 1858. N. 283.

The " Battler," a sloop-of-war built at Sheerness Dockyard in 1843, was
the first screw vessel constructed by the Admiralty. Her dimensions
were : Displacement, 1,078 tons ; Length (b.p.)., 176-5 ft. ; beam, 32- 7 ft. ;
mean draught, 13 5 ft. ; immersed midship section, 330 sq. ft.

The engines, of 437 indicated h.p., were of Maudslay's ' Siamese " type
(see No. 807), and were adapted to driving a screw shaft by the use of spur
gearing, which increased the revolutions of the screw to four times those of
the crank.

The screw is a gunmetal casting weighing 1'325 tons, is 10 ft. diam.,
11 ft. pitch, 1 56 ft. long, and has two blades. It was secured to the shaft
by a through cotter. The tips of the blades have been strengthened by
patches riveted on.

984. Aquatint representing a trial of paddle v. screw (1845).
Woodcroft Bequest, 1903. N. 89.

This represents H.M. screw sloop " Battler " fastened stern by stem to
H.M. paddle sloop " Alecto," and both steaming full speed ahead so as
to test the relative powers of the two methods of propulsion. The trial
took place in a calm on April 3rd, 1845, in the North Sea ; the " Battler "
towed the " Alecto " stern foremost at a speed of 2 -43 knots.

The "Battler's" engines had four steam cylinders 40 '125 in. diam. by
4 ft. stroke, and made 25 -76 revs, per min., which drove the screw (No. 983)
at 113 revs, per min. Her boiler pressure was 10 Ib.

The "Alecto" had direct-acting paddle engines, with two cylinders
53 '125 in. diam. by4'5ft. stroke, and drove paddle-wheels 23 ft. diam., with
radial floats. Her boiler pressure was 5 Ib. Although the two vessels were
very similar in size and nominal h.p., the contest was in other respects
inconclusive.



331

985. Lithograph representing a trial of paddle v. screw (1849).
Received 1860. N. 708.

This represents H.M. screw corvette " Niger " and H.M. paddle sloop
" Basilisk " engaged in a " tug-of-war."

The trial took place in the English Channel on June 20th, 1849, and
lasted for one hour, during which time the " Niger " towed the " Basilisk,"
stern foremost, 1*46 knots. The following particulars give some further
information :

" Niger." " Basilisk."

Length - - 194 -33 ft. 190ft.

Breadth - - 34 -66 ft. 34 -42 ft.

Engines - - Maudslay twin. Miller oscillating.

Indicated h.p. - 919

Cylinders - - Four 47 625 in. diam. Two 74-in. diam.

Stroke - - 22 in. 72 in.

Propeller - - Screw 12 '5 ft. diam., Radial paddle -

17 ft. pitch, 2-8 ft. wheel 24 ft. diam.

long.

Speed in knots 10-43 9 -75

Boiler pressure - 8 Ib. 10 Ib.

986. Model of the propeller of S.S. " Great Britain." (Scale
1 : 60.) Woodcroft Bequest, 1903. N. 1340.

This represents a propeller tried on the early screw ship " Great Britain,"
built at Bristol in 1843. It shows a six-bladedfan made in a single casting ;
but in the working model of the engines the screw represented has four
blades. ,

The propeller finally adopted was a built-up wrought-iron fan, of six
blades ; it was 15 5 ft. diam., and 25 ft. pitch, corresponding to an angle of
28 deg. Each blade had an area of 56 -25 sq. ft., or a projected area of
47*4 sq. ft. The outer edges of the blades were finished in a lathe; while
the faces were rubbed smooth and varnished. Further particulars of the
ship and engines are given in Nos. 187 and 820.

987. Drawing of screw propellers proposed before 1850.
Presented by Sir F. P. Smith, 1857. N. 709.

This drawing, compiled by Mr. E. J. Powell, indicates the distinctive
features of 28 of the most important screws patented in Great Britain ; it
was shown at the 1851 Exhibition. Many of the types are represented by
models in the collection.



SIMPLE SCREW PROPELLERS.

988. Stern model with propeller. (Scale 1 : 12.) Presented
1860. N. 15L

This model shows an arrangement that has been proposed by many for
increasing the efficiency of a propeller. The screw is placed on the stern
post and the rudder still further aft.

989. Model of propeller. (Scale 1 : 8.) Contributed by
F. H. Hodd, Esq., 1880. N. 1539.

This is a two-bladed screw with perforated blades, patented by John
Fisher in 1853. The perforations are slots parallel to the shaft and are
intended to discharge any cushioning air that may be on the blade face.



332

990. Model of two-bladed propeller. (Scale 1 : 12.) Contri-
buted by the Society of Arts, 1861. N. 437.

This screw is a modification of one patented by Mr. A. Mitchell, of
Belfast, in 1854. It is called the elliptical propeller, because the surface
of the blade along a radial line is curved with increasing curvature from the
axis to the circumference and is part of an ellipse.

The screw is intended to be auxiliary, and the most successful case of
its application was to the S.S. " Malvina," where it replaced a straight-
armed one. An increase of speed of 1*5 knots with lessened vibration, and
a decreased coal consumption of 25 per cent, is stated to have resulted.

991. Screw propeller. Presented by Henry Walduck, Esq.,
1857. N. 114.

This construction was patented by Mr. Walduck in 1854, to obviate slip
from centrifugal motion of the water. The surface of the blades is formed
in a series of terraces, concentric with the shaft but each of greater pitch
than its inner neighbour. The example is two-bladed and is 13 '5 in. diam.

992. Model of propeller. (Scale 1 : 12.) Presented by Messrs.
Bullivant & Co., 1902. N. 1893.

This is a screw with four somewhat tapering blades, which are curved
forward although remaining in the same plane. The sickle-like form so
obtained has been extensively adopted, with the intention of preventing
centrifugal motion of the water.

993. Model of two-bladed propeller. (Scale 1 : 12.) Pre-
sented by J. B. Oubridge, Esq., 1858. N. 149.

This represents the two-bladed screw propeller of H.M.S. " Thunderbolt,"
one of three floating batteries built of iron by Messrs. Napier of Glasgow
during the Crimean war. They were of the following dimensions : Tonnage,
1,973 tons ; length, 186 7 f t. ; breadth, 48 5 f t. ; depth, 15 54 ft. ; h.p., 200 ;
armament, sixteen 68 -pr. guns.

The screw has very wide blades and a fine pitch.

994. Model of two-bladed propeller. (Scale 1 : 8.) Contri-
buted by Capt. O. Peacock, R.N., 1862. N. 845.

This construction of screw was patented by Capb. Peacock in 1855, and
is intended to f orm a light propeller suitable for temporary use as an auxiliary
screw.

Each blade is built of iron plate strengthened with angle bars and
supported by a stay rod to the boss. The front face of the blade is dished,
and the greatest width is at one-third of the diameter. The whole of the
propeller was to be galvanised.

995. Whole model of vessel with twin screws. (Scale about
1 : 48.) Contributed by Capt. A. M. Skinner, R.N., 1861.

N. 421.

This shows the arrangement of twin screws patented by Capt. Skinner
in 1859. The screws are placed " very much before the stern post and
well under the quarters of the ship " ; two two-bladed screws are placed on
each shaft. The arrangement shown protects the propellers but interferes
with the lines of the vessel and with the flow of water to the screws.

The first twin screw vessel on the Transatlantic service was the S.S.
"Notting Hill," built at Glasgow in 1883 (420 "3 ft. long, 45 ft. broad,
26 '5 ft. deep, and 3,902 tons). Such screws had, however, been long in use
in the British Navy, and in 1840 Capt. E. J. Carpenter, B.N., patented the
use of a screw on each quarter, an arrangement that he applied to the
" G-eyser " pinnace.



333

996. Model of Hirsch's propeller. (Scale 1 : 12.) Maudslay
Collection, 1900. N. 2240.

This construction of screw was patented by Mr. Hermann Hirsch in
1860-66 and somewhat extensively adopted. The chief feature of the blade
is, that its section, by a plane perpendicular to the screw-shaft, is a spiral
with the leading edge concave, the intention being to prevent centrifugal
movement of the water. The blade has increasing pitch and tapers con-
siderably from the centre towards the tips.

The propeller represented has four separate blades, fixed by flanges and
screws to the boss ; it is 24 ft. diam. and is intended for utilising 7,000
indicated h.p.

997. Model of Hirsch's propeller. (Scale 1 : 20.) Presented
by Walter Child, Esq., 1908. N. 2501.

This model represents the four-bladed screw-propeller of the S.S.
" Periere," a vessel built in 1865-6 by Messrs. R. Napier and Sons for the
Compagnie Generale Transatlantic^. The " Periere " was originally fitted
with a four-bladed Griffiths screw, 19 ft. diam. and 29 5 ft. pitch, so that
the propeller represented must have replaced it subsequently.

' It differs slightly from No. 996, which has blades bolted to the boss.

Particulars of the vessel are : Displacement, 5,100 tons ; length, 339 ft. ;
breadth, 43 5 ft. ; depth, 29 ft. ; load draught, 22 ft. The average h.p. exerted
at sea was 2,500, giving a speed of 13' 5 knots, with a steam pressure of
25 Ib. per sq. in. On the measured mile at Cherbourg breakwater in 1866 a
mean speed of 15*3 knots was obtained.

998. Experimental ship-model with Rigg's guide-blade
propellers. Received 1909. N. 2523.

This is the original model used by Mr. Arthur Rigg, jun., in 1863-64, at
Chester, for testing the efficiency of various forms of re-action or guide-
blade propellers. The essential idea of using fixed vanes or reverse blades
at the rear of the ordinary screw propeller (or paddle-wheel) is to utilise
any available momentum in the water leaving the revolving blade in order
to increase the total propulsive effect.

On the model are shown, in their relative position, two 12-bladed screws,
each 3 in. diam. ; the foremost, or revolving screw, is attached to a shaft
driven by internal spring mechanism, while the rearmost or fixed screw,
with reversed deflecting blades, is separately attached to a hanging bracket
or stern-frame. This latter frame is removable and provided for the inter-
change of differing forms of both revolving and fixed blades. Enclosing
both screws was a cylindrical casing arranged concentric with the axes ;
this casing or tunnel limited the volume of water affected by the propellers,
and was specified in Mr. Rigg's original patent of 1864 ; it has also formed
an integral part of the arrangements adopted by later investigators.

In addition to experiments with the model propellers here shown, and
many others similar in size but varying in pitch, curvature and number of
blades, Mr. Rigg's plans were tried on a small boat fitted with a 3-ft. pro-
peller, and also on the S.S. " Corcyra," with a 12-ft. propeller. The guide-
blade principle was tested by the Admiralty on H.M.S. "Bruizer " in 1875,
and also by Sir J. I. Thornycroft, on H.M.S. " Lightning " in 1877-83 (see
No. 116). Although on some of these trials an increase of speed and
reduction of vibration were recorded, they were not uniformly satisfactory.

In 1866 Messrs. Rigg and Griffiths patented an arrangement of guide-
blade propeller in which adjustable blades were proposed in place of rigidly
fixed ones.

999. Model of propeller of H.M.S. "Lord Warden." (Scale
1 : 16.) Maudslay Collection, 1900. N. 2239.

The " Lord Warden " was an armoured wooden vessel of 7,675 tons
displacement, launched in 1865 ; her engines were similar to those of the



334

" Octavia " (see No. 839) and indicated 6,705 h.p., which gave a speed of
IS -5 knots.

The four-bladed propeller represented was 22-8 ft. diam., 21 -37 ft. pitch
and 11 '7 ft. long. The blades were fixed to the boss by flanges, with
slotted holes for the studs so as to allow of the pitch being altered. A
two-bladed screw was also tried on this vessel, but was found less efficient,
although more convenient as an auxiliary propeller.

1000. Stern model with screw propeller. (Scale 1 : 24.) Con-
tributed by W. H. Crispin, Esq., 1861. N. 433.

This propeller was patented by Mr. Crispin in 1860. It resembles a
two-bladed screw, but the blades are flat discs set at an angle ; two
modifications are shown.

1001. Model of screw propeller. (Scale 1 : 4.) Presented by
Mrs. H. Vansittart, 1874. N. 1369-70.

This two-bladed screw was patented in 1868 by Mrs. Vansittart, daughter
of James Lowe, and named the " Lowe- Vansittart " propeller.

Each blade has a surface of varying pitch, and is rectangular in outline
with rounded corners. The root of each blade is flanged out, and fixed .to
the boss by studs.

This screw was fitted by the Admiralty in 1869 to several warships, and
in 1873 the Allan Liner "Scandinavian" had its propeller, which was
18 ft. diam. by 25 ft. pitch, replaced by a Lowe- Vansittart screw with very-
favourable results.

1002. Model of De Bay's propeller. (Scale 1 : 8.) Lent by
C. W. Crossley, Esq., 1910. N. 2554.

This represents the propeller of the steam yacht " lolair," a schooner-
rigged vessel, 81 ' 5 ft. long, 12 ft. beam, and 8 '17 ft. deep, with a gross
tonnage of 40 '37. The type of propeller shown was patented in 1876 by
Mr. C. S. De Bay. It consists of two screws of equal and opposite pitch,
mounted on the same shaft and revolving in opposite directions. The
diameters of the screws differ slightly, the larger having three blades and
the smaller four blades. Portions of the blades of each propeller are cut
out and the remaining portions of the blades of each screw revolve in the
spaces left in the blades of the other screw.

This construction is an attempt to prevent the loss of energy caused
both by centrifugal motion of the water acted upon, and by all other motions
of the water except that in an astern direction parallel to the keel of the
vessel. It was held that wasteful motions of the water caused by one pro-
peller would be neutralised by similar motions in an opposite direction caused
by the other propeller, and the final effect would be for the pair of propellers
to drive the water in a true astern direction.

The mechanism employed in order to obtain the reverse motions of the
screws consists of a tubular shaft attached to the four-bladed screw through
which runs the shaft carrying the other screw. The inner shaft ia driven
direct from the engine, and the tubular shaft, which runs loose on it, is
driven in the opposite direction by a pair of spur wheels, the motion being
transmitted to th3 spur wheels by cranks and connecting rods from the
inner shaft. The spur wheels have stepped teeth so that the wheels can be
moved circumf erentially for taking up wear.

The special form of the framing shown was designed to enable the gear
to be put as far aft in the vessel as possible.

Comparative trials of a propeller of this construction and a four-bladed
Griffiths screw similar to that of H.M.S. " Lord Warden " (see No. 999) were
made with specially designed apparatus in 1879, and are stated to have
indicated an increased efficiency of at least 40 per cent, in favour of the
De Bay propeller.

On trial, the "lolair," with a four-bladed Griffiths propeller of 6 -17 ft.
diam. and 6 34 ft. pitch, is stated to have obtained a speed of 7 4 knots



35

at 124 revs, per min. When fitted with the propeller shown in the model,
of 4-67 ft. diam. and 7*5 ft. pitch, the vessel is stated to have obtained a
speed of 8 '3 knots at 128 revs, per min., representing a gain of nearly
1 knot on the speed of the vessel.

1003. Model of screw propeller. (Scale 1 : 24.) Presented by
R. Griffiths, Esq., 1881. N. 1542.

This is a form of four-bladed screw, patented in 1880 by Mr. W. J. '
Griffiths. The leading edges of the blades are convex for the whole length,
while the after edges are convex near the root and concave near the point,
the point of inflection being half-way. The blade surface from about two-
thirds of the radius to the point is curved or bent forward. These features
were introduced to reduce vibration.

1004. Model of torpedo-boat propeller. (Scale 1 : 4.) Pre-
sented by J. K Rennie, Esq., 1879. N. 1514.

This screw was designed for shallow draught vessels, in which the
diameter is very restricted.; the area obtainable is increased by bending
the blades aft ; this also prevents centrifugal motion of the water.

The blades are wedged into the boss from the end, and held in place
by a conoidal cap. The propeller represented was 5 '4 ft. diam., and 6 ft.
pitch.

1005. Model of stern framing witli Duncan's propeller. (Scale
1 : 12.) Presented by Messrs. Ross and Duncan, 1887.

N. 1705.

This represents the stern of the Egyptian Government yacht " Sareea,"
built in 1886, and fitted with Duncan's screw propeller. The dimensions of
the vessel are : Length (o.a.), 68 ft. ; length (b.p.), 63 "4 ft. ; beam, 12 ft. ;
depth, 6-1 ft. ; depth (moulded), 7 ft.

The extremities of the blades are curved aft and are somewhat dished,
the object being to prevent centrifugal motion of the water.

The engines are of the two-stage expansion, inverted cylinder, surface
condensing type, with cylinders 10 in. and 20 in. diam., by 14 in. stroke,
supplied with steam at 100 Ib. pressure by a double furnace multitubular steel
boiler. On the trial trip the mean speed was 9*5 knots, the engines
indicating 120 h.p. at 200 revs, per min.

1006. Motor-boat propeller. Presented by Messrs. D. Ramsay
Smith & Co, 1909. N. 2510.

This represents a typical form of propeller used in high-speed motor
boats of fine lines and small displacement. It has three right-handed
blades of oval form, with an increasing pitch both towards the tips and
from the leading to the following edges of each blade. The blades are
dipped aft in order to concentrate the column of water acted upon and to
avoid centrifugal action of the water. The design of this propeller is
stated to be such as to reduce cavitation to a minimum. The material
employed is bronze, toughened to withstand shock.



SCREW PROPELLERS WITH ADJUSTABLE BLADES.

1007. Models of adjustable pitch propellers. (Scale 1 : 8.)
Woodcroft Bequest, 1903. N. 34-5 and 37.

These show modifications of the adjustable pitch screw patented by
Mr. Bennet Woodcroft in 1844; the blades have the increasing pitch
patented by him in 1832.

The object of altering the pitch or angle of inclination of the screw is
to find experimentally the most efficient angle, and also to enable the



336

engines to give out their full power under varying states of wind, load, etc.,
as these seriously affect a vessel in which the screw is auxiliary.

(a) Shows a two-bladed screw with an arm fitted to the stem of each
blade ; a block on the end of the arm slides in an inclined groove in a
collar, which slides on a feather and is moved by a lever on deck.

(6) Resembles (a), but has a four-bladed screw, and the sliding collar is
moved by bell- crank levers from a spindle worked by a hand -wheel on deck.
An indicator shows the angle of the blades.

(c) Another modification of (a) ; instead of grooves on the collar, there
are short links from it to the arms of the blade stems. For fixing the
blades in any position a similar collar is provided aft, with two wedge-
shaped arms which act on small sliding pieces that lock the stems.

1008. Woodcraft's adjustable pitch propeller. Contributed by
the Lords of the Admiralty, 1857. N. 36.

This is the first propeller constructed in which the pitch of the screw
could be varied. It was made by Messrs. J. Whitworth & Co. in 1845, to
the order of the Admiralty, after they had seen the Woodcroft model,
No. 1007 (a), for trial on H.M.S. "Dwarf" (see No. 982), but was never
fitted.

The propeller is 5' 75 ft. diam., has two blades 2-5 ft. wide, and a pitch



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