IMPROVEMENTS IN PROPELLING AND STEERING VESSELS
Year: 1867

page_text: LETTERS PATENT to Charles Mayo, of New College, Oxford, for the
Invention of "IMPROVEMENTS IN PROPELLING AND STEERING VESSELS."
Sealed the 28th January 1868, and dated the 30th July 1867.
PROVISIONAL SPECIFICATION left by the said Charles Mayo at the
Office of the Commissioners of Patents, with his Petition, on the 30th
July 1867.
I, CHARLES MAYO, of New College, Oxford, do hereby declare the nature
of the said Invention for "IMPROVEMENTS IN PROPELLING AND STEERING VESSELS,"
to be as follows:-
This Invention has for its object improvements in propelling and steering
vessels. In order to obtain the greatest amount of effect from the propelling
power I apply the force in a line passing through the centre of resistance of
the body parallel or nearly parallel to the surface of the water.
The method of steering which I employ is such that a large proportion of
the propelling force can be applied in the direction required. A tunnel or
passage of cylindrical or other form is made through the vessel in the direction
of its length passing through the average position of the centre of resistance
and parallel to the surface of the water. The propelling instrument is placed

page_text: at the middle of the tunnel at or about the centre of gravity of the vessel.
More than one tunnel may be used if required. It is preferred to employ a
screw revolving in the tunnel on an axis coincident with that of of the tunnel, or
a centrifugal pump or turbine or other contrivance may be resorted to, and
the propelling instrument may be driven by a steam engine or by other means.
There is placed in the sternmost aperture of the tunnel or in each aperture a
rudder consisting of a plate of a circular or other form capable of revolving
on a vertical axis. The axis of this plate or rudder is controlled from above
in the usual way, and it intersects the axis of the tunnel at right angles.
The advantages obtained by this Invention are,-
1. Increased speed by reason of the direct application of the force and
utilization of the whole of it, the loss of power incurred by the throwing off of
masses of water in wrong directions in the case of paddles and screws as
ordinarily applied being avoided.
2. Complete protection from shot, fouling, and collisions.
3. Absence of vibration.
4. Very great facility of steering.
racing" of the
5. Freedom from the disadvantages incurred through
screw in pitching and unequal immersion of the paddles in rolling.
6. No diminution of sailing powers.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles Mayo in the Great Seal Patent Office on the
30th January 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
MAYO, of New College, Oxford, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirtieth day of July, in the year of our Lord
One thousand eight hundred and sixty-seven, in the thirty-first year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Charles Mayo, Her special licence that I, the said Charles
Mayo, my executors, administrators, and assigns, or such others as I, the
said Charles Mayo, my executors, administrators, and assigns, should
at any time agree with, and no others, from time to time and at all
times thereafter during the term therein expressed, should and lawfully
might make, use, exercise, and vend, within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an Invention

page_text: the con-
for "IMPROVEMENTS IN PROPELLING AND STEERING VESSELS," upon
dition (amongst others) that I, the said Charles Mayo, my executors or
administrators, by an instrument in writing under my, or their, or one of
their hands and seals, should particularly describe and ascertain the nature
of the said Invention, and in what manner the same was to be performed,
and cause the same to be filed in the Great Seal Patent Office within
six calendar months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said Charles Mayo, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement thereof, that is to say:-
In order that a propelling force applied to a body floating in a fluid may
produce the greatest effect it must be applied in a line passing through the
centre of resistance of the body, or if more than one force be employed the
resultant of the forces must similarly pass through the centre of resistance
and be parallel to the surface of the fluid. If the propelling instrument be
removed from the centre of resistance of the body the further it is so removed
the more are the vibrations produced by it intensified, and all power employed
in producing vibrations is subtracted from the effective force exerted by the
motive agent.
According to my Invention in order to apply the motive power under the
most advantageous conditions it is proposed to make one or more tunnels
passing through the vessel from before aft in such a position that the axis of
the tunnel, or the resultant in case of more than one, shall pass through the
centre of resistance in a direction parallel to the surface of the water; and it
is further proposed to place the propelling instrument (which I prefer to be.
a screw, in the tunnel revolving on an axis coincident with that of the tunnel)
as near as may be to the centre of gravity of the vessel. In sea-going ships
it will be advisable to make two tunnels, one on each side of the line, passing
through the centre of resistance in order to avoid affecting the stability of
the ship by the weight of a central tunnel and its contents. In vessels for
harbours and canals one tunnel will be sufficient.
The screw propellor, or each of them if more than one be employed, may
be driven by means of bevilled wheels, these gear wheels being kept as small
as may be so that they may not materially impede the flow of water through
the channel; they may be protected from the stream by a suitably shaped
screen; or the screw may be driven by a pulley on its axis receiving a driving
belt, the pulley and belt being enclosed in a trunk through the sides of which

page_text: the shaft of the screw passes.
Within the ship if bevilled gear be employed
I provide multiplying gear between the intermediate shaft and the engines
so that the screw may be driven three or four times as fast as the engines run
to allow of a corresponding reduction being made in the size of the screw and
in the area of the tunnel. It is also proposed in each orifice of each tunnel
to place a vertical plate of metal of circular or other form revolving on a
vertical axis intersecting that of the tunnel, the plate to be controlled by a
tiller or other instrument.
Figure 1 is a side view, Figure 2 a plan, and Figure 3 is a transverse
section of a vessel thus arranged.
a, a, are the propeller tunnels; b, b, the propellors therein with their axes
parallel to the length of the vessel and in the same horizontal plane with
the centre of resistance and equidistant from it; c, c, are the steering dises;
they are employed in one direction only to direct the current of water
through the tunnel away from the side of the vessel. Slide valves are
provided near the ends of the tunnels to close them when the vessel
sails.
The advantages secured by this plan are,―
1. Increased speed by reason of the utilization of nearly the whole of the
power generated by the coal burnt.
(a.) By avoiding the loss incurred by the throwing off of water in wrong
directions from the paddles and screw, and from slip and racing of the screw
in pitching, and from unequal immersion of paddles in rolling, and by
vibrations.
(b.) By bringing the propelling instrument close to the engines.
(c.) By avoiding the formation of eddies for the after body of the ship to
move in.
(d.) By making the column of water contained in the tunnel pass freely
through the ship with the smallest amount of friction, and by compelling all
the water that has passed the screw to pass out in a straight line astern and
transmit the pressure of the engines directly to the mass of water which is
the fulcrum.
2. A facility of steering not obtained by any other method, nearly the whole
of the propelling power in the case of one tunnel and nearly half in the case
of two tunnels being used directly for this
purpose.
3. Complete protection of the propelling apparatus from shot, fouling, and
collisions.
4. Facility of repair. The tunnels being closed by floodgates the water
can be pumped out, the tunnel opened, and the screw taken out and repaired

page_text: without docking the ship; and the screw being small a vessel could carry
spare ones and put them in position even at sea.
5. No diminution of sailing powers.
6. Freedom from vibration.
In witness whereof, I, the said Charles Mayo, have hereunto set my
hand and seal, this Thirtieth day of January, in the year of our Lord
One thousand eight hundred and sixty-eight.
5. No diminution of sailing powers.
6. Freedom from vibration.
In witness whereof, I, the said Charles Mayo, have hereunto set my
hand and seal, this Thirtieth day of January, in the year of our Lord
One thousand eight hundred and sixty-eight.
CHARLES MAYO. (L.S.)