IMPROVEMENTS IN PROPELLING APPARATUS FOR SHIPS AND OTHER VESSELS
Year: 1870

page_text: PROVISIONAL SPECIFICATION left by Martyn John Roberts at the
Office of the Commissioners of Patents, with his Petition, on the
7th April 1870.
I, MARTYN JOHN ROBERTS, of Pendarren, near Crickhowell, in the
County of Brecon, Esquire, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN PROPELLING APPARATUS FOR SHIPS AND OTHER
VESSELS," to be as follows:-
My Invention relates to a new or improved apparatus for propelling
ships or other vessels, and which may be employed either as an auxiliary
This new or
and removable propeller, or as a permanently fixed one.
improved propeller consists of a rod or arm suspended at the side or
other suitable part of the ship or vessel and vibrating like a pendulum,
which vibration may be produced by steam or other power. Upon this
rod another rod or arm is made to slide, and the lower end of this latter
rod is formed into a blade or float, or a blade may be attached to it in
any desired manner; it is the motion of this blade in the water which
propels the ship. By sliding the arm of this blade upwards upon the
upper arm the blade is raised out of the water in a direction parallel
or nearly parallel to the length of the arm, and this can be elleted by

page_text: means of a lever or other device actuated by a stop, cam, or rope,
attached to the ship. When the blade is thus raised the arms make
their return vibrations or stroke without hindrance from any resistance
from the water, then the lever by aid of the stop or other device causes
the blade arm to slide downwards, and the arm now making another
stroke (the blade being in the water) propels the ship. I sometimes
place on the lever a weight which nearly balances the weight of the
arm and blade, thus enabling the sliding motions of these to be effected
by a small expenditure of force, and the lever which thus moves the
arm is also sometimes so adjusted that a weight attached to it passes
over the centre of motion at the expiration of each stroke, and thereby
retains the blade up or down as may be required, or a catch may be used
for the like purpose, but I prefer the weight on the lever. Sometimes
instead of sliding the lower arm or blade shaft upon the upper arm I
raise this lower arm by means of levers somewhat in the manner of the
blades of a parallel ruler, or sometimes simply raise the lower arm and
blade out of the water by turning the arm upon a pivot; but I much
prefer the sliding the lower arm upwards and downwards the
upon
vibrating arm. It is very desirable that the motion of the blade in
the water shall be uniform, and if the arm was mado to vibrate by a
connecting rod to a revolving crank, it is evident that if the circular
motion is uniform the horizontal motion of the connecting rod and the
vibration of the arm cannot be so. I therefore prefer (if steam be the
power employed) to put the arm in motion from the piston rod without
the intervention of a revolving wheel or crank, and the piston and rod
are governed in their motions somewhat in the manner of the piston of
a steam hammer.
upper
I have described the apparatus for moving one float only; such
apparatus may be multiplied for several floats or blades on the side of a
ship, but I prefer (if several blades are required on one side) fixing
them to a bar suspended to two or more vibrating arms, which bar being
attached to the lower or sliding arms is raised or lowered in the same
manner as I have explained with reference to the single blade.