IMPROVEMENTS IN CON- STRUCTING AND PROPELLING SHIPS AND OTHER VESSELS
Year: 1869

page_text: LETTERS PATENT to Alan Lawrie McGavin, of Barge Yard, Bucklers-
bury, E.C., Merchant, for the Invention of "IMPROVEMENTS IN CON-
STRUCTING AND PROPELLING SHIPS AND OTHER VESSELS."-A communication
from abroad by Benjamin Dickinson, of Hopetown, Darjeeling, India,
Tea Planter.
Sealed the 5th November 1869, and dated the 19th May 1869.
PROVISIONAL SPECIFICATION left by the said Alan Lawrie McGavin
at the Office of the Commissioners of Patents, with his Petition, on
the 19th May 1869.
I, ALAN LAWRIE MCGAVIN, of Barge Yard, Bucklersbury, E.C.,
Merchant, do hereby declare the nature of the said Invention for "In-
PROVEMENTS IN CONSTRUCTING AND PROPELLING SHIPS AND OTHER VESSELS," the
same being a communication to me from abroad by Benjamin Dickinson,
of Hopetown, Darjeeling, India, Tea Planter, to be as follows:-
This Invention consists in constructing or altering the immersed
portions of the hull of a ship or other vessel as hereafter described, so

page_text: as to admit of the application of the propelling apparatus herein-after
described, which consists of a peculiar method of applying a screw or
screws, or some other well know propellor or propellors to the bottom
or near to the bottom of a vessel in such a manner that the water
actuated by such propellor or propellors is wholly or partially confined
laterally and vertically or laterally only, the vessels when so constructed
or altered so as to confine (wholly or partially) laterally and vertically
or laterally only the water actuated or to be actuated by the propelling
power.
I prefer in some cases to place a shaft running wholly or partially
along the bottom of the vessel upon which is fitted one or more screws,
and which is caused to revolve by suitable power placed in the vessel,
suitable guide or channel plates are formed in or on, or are fitted to the
bottom of the vessel in such a manner that they confine the water
acted upon by the screw or screws in such a manner that the whole
or nearly the whole of the useful effect is obtained from such water.
That portion of the connection between the driving power and the screw
shaft which is under water may be enclosed, and such enclosure being
made sharp fore and aft to offer as little resistance as possible to the
water when the vessel is moving, the channel for the water being
divided at that place, or when such connection is near the bow or stern
of the vessel it may be entirely within the vessel and the water taken
in or driven out by curved or angular channels at the bow or stern
respectively. In some cases in the place of screws one or more paddles
or inclined surfaces may be used to act upon the water within the
channel.
Instead of a single channel running along the bottom of the vessel I
prefer sometimes to employ two channels, one on each side of the keel
or centre line of the vessel, the keel being extended to a sufficient depth
to divide the two channels, or these channels may be further apart by
being fitted with plates upon both sides, the methods of propulsion in
each channel being any of those herein-before mentioned.
In order to preserve from injury the various apparatus or machinery
above described, instead of placing the channels below the bottom of
the vessel as a projection or projections therefrom, I prefer where it can
be done to construct the vessel with a channel, tubular passage, or
tunnel along the entire length or a portion of the length of the ship's
bottom, in such a manner and of such dimensions that the screw or

page_text: other propelling apparatus will be protected when the bottom of the
vessel "takes the ground" or comes against any hard substance, and
instead of one tunnel along the centre of the bottom of the vessel two
tunnels or channels may be formed, one on each side of the keel, and
for convenience of applying the driving power they may be curved or
bent horizontally or vertically near the point of connection between the
driving power and the propelling apparatus.