IMPROVEMENTS IN THE CONSTRUCTION OF SHIP3 AND VESSELS, AND IN MACHINERY OR APPARATUS FOR PRO- PELLING AND DIRECTING THE SAME
Year: 1851

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
JOHN CARPENTER, of Toft Monks, in the County of Norfolk, Esquire, Captain
in the Royal Navy, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Thirteenth day of May,
(One thousand eight hundred and fifty-one,) in the fourteenth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Edward John Carpenter, my exors, admors, and assigns, Her especial license,
full power, sole privilege and autliority, that I, the said Edward John Carpenter,
my exors, adñiors, and assigns, or such others as I, the said Edward John Car-
penter, my exors,. adiiors, or assigns, should at any time agree with, and no
others, from time to time and at all times during the term of years therein
expressed, should and lawfully might make, use, exercise, and vend, within
England, Wales, and the Town of Berwick-upon-Tweed, and in the Islands of
Jersey, Guernsey; Alderney, Sark, and Man, and also in all Her said Majesty's
Colonics and Plantations abroad, my Invention of "IMPROVEMENTS IN THE
CONSTRUCTION OF SHIP3 AND VESSELS, AND IN MACHINERY OR APPARATUS FOR PRO-
PELLING AND DIRECTING THE SAME;" in which said Letters Patent is contained a
proviso that I, the said Edward John Carpenter, shall cause a particular
description of the nature of my said Invention, and in what manner the said
is to be performed, by an instrument in writing under my hand and seal, to be
inrolled in Her said Majesty's High Court of Chancery within six calendar
months next and immediately after the date of the said in part recited Letters

page_text: Patent, as in and by the same, reference thereunto being had, will more fully
and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Edward John Carpenter, do hereby declare that the nature of my said Inven-
tion, and in what manner the same is to be performed, are fully described and
ascertained in and by the present Specification thereof, reference being had to
the Drawings hereunto annexed, that is to say :-
Firstly, my Invention, in so far as it regards improvements in the construc-
tion of ships and vessels, has exclusive relation to ships and vessels which are
intended to be propelled by means of screws or other submerged instruments
worked by steam power, either alone or in combination with wind or other
power, and have for their object the adaptation of such ships and vessels to be
worked by two propellers instead of by one only as usual. Figures 1, 3, 4, 8,
and 9 of the Drawings annexed, are different views of a vessel fitted with two
screws (S, S,) and Figures 2, 5, 6, and 10 analogous views of a vessel con-
structed or designed for propulsion by one screw only (S). By comparing
the one set of these Figures with the other, the differences in point of con-
struction between them will be readily recognized. The ordinary rudder, stern
post, dead wood, and after parts of the keel are removed, and the space in the
hull hitherto appropriated to them is enclosed within a strong framework open
to the water both fore and aft, and beneath, the two sides of which terminate
at bottom in two additional keels or bilge pieces parallel to the main keel.
It is intended that the two propellers aforesaid should work in the water space
enclosed within this framework in the same way as the single screw now com-
monly works in a space cut out for it in the dead wood. In Figures 3 and 4,
ff, represent the above framework, and f', f', the water space within the
same; c represents the starboard additional kcel; d, the port additional keel;
and e, the main or midship keel. The flooring immediately over the framework
and water space has an arched form given to it for the sake of giving strength
to the after-frame of the vessel, and in order that the water may flow the more
freely through the enclosed space beneath towards the propellers. The water
space,, is constructed with a gradual inclination downwards from the water
line between the two stern posts as far as the point where the main keel begins
to chango its original line of direction. The additional keels terminate each
in a separate stern post, (b, b, Figure 9,) and each stern post has a separate
rudder attached to it. A steering wheel or apparatus should be used capable
of steering either with two rudders moving together in parallel lines or sepa
rately. The distances between the additional side keels and the midship keel will
of course depend on the diameter of the screws, and that again will depend on

page_text: the quantity of propelling surface and steam power proposed to be employed.
The exterior sectional lincs (1, 2, 3, 4, 5, 6, 7, 8, Figure 9,) are carried from
the midship section aft in the usual way followed in ship building, allowing for
the distance each keel and steru post will be removed from the position cccu-
pied by these parts in ships on the old plan of construction, and the interior
lines are curved from the flooring to each keel, so as to allow the water to pass
away with as little obstruction as may be. The variation in these lines will be
better understood by referring to Figure 10, where the numbers 1, 2, 3, 4, 5, 6, 7,
and 8 represent the sectional lines of a vessel having one keel only, and adapted
to propulsion by one screw only. From the midship section to the stern, or
from the point where my alterations in construction commence to the stem, the
construction would be the same as usual.
Secondly, my Invention, in so far as it regards the machinery or apparatus
for propelling vessels, consists in substituting for the one screw or submerged
propeller now ordinarily employed, two propellers placed in the water space
formed aforesaid, the one a little in advance of the other, and which may be
worked either both at the same time, or one only at a time. Each screw may
be made of a diameter equal to that of a full-sized screw of the sort commonly
used, when placed in a space cut out of the dead wood, that is to say, of as
large a size as the distance between the water line and the bottom of the keel
will admit of, so that when one only of the two screws is worked the power
obtained will be equal to that now obtained from single screw propellers, and
when both are worked an increase of power more or less considerable will be
realized, and that even though no more steam should be expended. Why
more speed should be obtained without the use of more steam, I account for
as follows:-A single screw placed in the deadwood for the purpose of moving
the vessel onwards loses power in four different ways: First, by slip, which is
owing to the blades of a single propeller not having sufficient surface to over-
come the heavy weight of a vessel without the water first yielding to the
pressure of the screw, which water should act in the same way as a nut does
to a screw; secondly, from the single screw revolving in water which has
previously been disturbed, and has not had time to settle into its ordinary
density, the propeller is always working to disadvantage; thirdly, a single
screw has a tendency to turn the vessel away from a straight line in its course,
and consequently the rudder is absorbing power, which lessens the speed;
fourthly, when a vessel, fitted with a single screw, is pitching, the propeller is
revolving at times without producing effect, from the blades being placed all
on one shaft, and that shaft placed in the midship line of the vessel, while the
propeller is at the extremity of the vessel. I have found by my experiments

page_text: that these objections are very much overcome by the use of the two propellers,
and that a considerable saving of fuel is effected by the second or auxiliary
propeller picking up the power that is wasted by the single screw. I have also
found by my experiments that two screw propellers of much less size and weight
than a single screw will produce more speed with an equal amount of power;
also, that two rudders in connection with the two screws will turn a vessel
about in a much shorter space than heretofore. I have also found by my
experiments, that by disconnecting one screw, and filling up the orifice, that
the opposite screw may be used for propelling as it formerly was when placed
in the midship line of the vessel. Again, the vibration complained of in screw
vessels is much diminished when two screws are employed, and by having two
screws at command, the risk of stoppage of the vessel is also greatly lessened,
for though one might be damaged, the improbability is great of both being
damaged at the same time. The screws being in advance the one of the other
revolve quite free of each other; but I wish it to be understood that I do not
regard it as indispensable that they should be placed at the exact distance
apart represented in the Drawings, for that they may without material
prejudice be placed more or less forward, or more or less aft.
Thirdly, my Invention consists of an improved form of screw propeller, which
may be used either where two propellers are employed as aforesaid or one only,
and either in a space cut out of the dead wood, or in a space formed as
described under the first head of this Specification. Figure 7 is a side view
shewing the manner of constructing this propeller. The vanes or blades are
here represented as perfectly flat, and set vertical on the shaft ready to be
twisted into the required form; and the Diagram, Figure 11, exhibits the
geometrical construction necessary to be observed in the production of that
twist. A, B, represent the propeller shaft; C, C, the propeller blades, which
may be constructed of metal or wood or any other suitable material. The
strength and superfices to be given to them will depend upon the size and
weight of the vessel to be propelled. At the ends on the line m, n, these
blades are made perfectly flat; but as it is necessary that the water should
pass away freely towards the axis of the shaft in its rotation, they are on that
account to be partially curved from the lines m, n, towards the shaft or line
E, F; but the curve is not a curve which, if continued, would form a com-
plete screw, but one which admits of the extremity of the blade or its flat
surface being set at the angle of 22°, and that part near the boss at the angle
of 67, or nearly so. Suppose, for example, A, B, Figure 11, to represent
the axis of the propeller shaft, and C, D, blades set vertical on that shaft, and,
in the first instance, perfectly flat surfaces; then, if the blades are turned

page_text: round on their own axes towards the line E, F, they will be set at the angle
of 221 represented by the arc Q, R. Again, suppose the upper parts of the
blades to be fixed, and the lower to be gradually twisted on their respective
axes towards the line G, H, near to the shaft (equivalent to the line m, n,
Figure 7, they will on that line be bent to an angle of 67°, the general
result being that the blades are part flat and part curved. I do not confine
myself, to two blades, as three or four blades formed in the same way may be
used on the same shaft; neither do I confine myself to the precise angles above
specified as to the proportions represented in Figures 7 and 11, deeming this
only to be of essential importance that the blades shall, as before said, be part
flat and part curved.
Fourthly, my Invention consists of certain improved arrangements whereby
the improved propeller, before described, or any other, may be wholly lifted
out of the water, or tho vanes or blades may be shifted or "feathered" at
pleasure without lifting the propeller shaft along with them. To lift the pro-
peller wholly out of the water a chock is placed between the two posts, which
form the frame for lifting the propeller in the usual way, having grooves in
them to guide the propeller shaft. On this chock there is fixed a rod or appa-
ratus for lifting it up or lowering it down to the blades. On each side of the
chock there is a strong metal plate which overlaps the edges of the post, and
serves both to guide the blades and to sustain their pressure. Underneath the
chock there is attached a strong metal plate to admit of the blade abutting
against it; then, by means of a lever or levers grasping the blade firmly, the
propeller may be lifted up by the chock, without having recourse to any such
cumbrous machinery as that now commonly employed for the purpose. To enable
the blades to be shifted at pleasure it will be necessary that they should be made
to put on and take off, (which may be done by a key being let into the shaft,
and continued so that it shall pass through the lower part of the blade, and in
various other ways,) so that with the assistance of my improved mode of lifting
the propeller and auxiliary gripping lever or levers, before described, the propeller
blades can be. lifted on deck separately instead of lifting the shaft along with
them. Flat blades may afterwards be attached to the boss to lie in a straight
line with the shaft which will fill up the aperture, and in that way be of advan-
tage to a vessel while sailing. In addition to the advantages before stated, as
resulting from the employment of the two propellers, and the arrangements
connected with them, the following are deserving of mention:-The vessel will
be on a better construction for strength in the after part for steam propulsion.
There will be encreased breadth for accommodation aft; also for carrying guns
in the stern and on the quarters. There will be more bearings for carrying

page_text: heavy weights aft, and the engine or engines may consequently be brought
further aft. The vessel will be able to turn round quicker and steer better,
going ahead or backing astern. She will hold a better wind when sailing,
and descend into the water astern easier, scud safer, and roll easier; she will
start quicker and stop sooner than with a single propeller. The propellers
will have a more solid mass of water to revolve in, therefore they will have
more resistance and less slip, consequently they will give more towing power,
less loss of power from the engine, and greater speed. As the motive power
may be divided, half on one side and half on the other, from the engines, the
weight of the machinery will be better disposed. The propellers and gearing
will be of less weight, therefore they will be more easily handled, and there will
not be such a dead weight lodged over the keel or in one point in the stern
near the rudder; the propellers will be under water, therefore out of the reach
of gunshot. The framework on one side will be a protection for the other
against shot or in gales of wind. In action, in the event of one rudder being
shot away, or one propeller being disabled from the wreck getting foul of it,
the other propeller and rudder could be used, while, with a vessel fitted with a
single rudder and a single propeller only, she would be disabled. The two-screw
plan is farther peculiarly adapted to line-of-battle ships as an auxiliary power,
also to boats or vessels having a shallow draught of water, and requiring an
encreased area in the screw propeller.
And having now described my said Invention in the several parts thereof,
and pointed out the advantages thereof, I declare that there are parts before
described which are old and well known, and therefore not meant to be set
forth by me as of my Invention; but that the improvements which I limit
myself to and claim are as follows:-
First, I claim the constructing of ships or vessels with a water space formed
out of the hull for screws and other submerged propellers to work in, by the
removal of the ordinary rudder, stern post, dead wood, and after part of the
keel, and enclosing with a framework the space heretofore occupied by these
parts, as before described:
Second, I claim the employment for the propelling of ships and vessels o
two propellers placed in the water space so formed as aforesaid, the one a littl
in advance of the other, and capable of being worked either both at a time o
one at a time only:
Third, I claim the improved form of propeller represented in Figures
and 11, and before described, having blades, parts of which are flat and part
curved:
And fourth, I claim the improved arrangements before described for raisin

page_text: propeller blades out of the water, or, in other words, "feathering" them,
without raising or shifting the propeller shaft along with them.
In witness whereof, I, the said Edward John Carpenter, have hereunto
set my hand and seal, this Thirteenth day of November, One thousand
eight hundred and fifty-one.