IMPROVEMENTS IN SCREW PROPELLERS
Year: 1862

page_text: LETTERS PATENT to Thomas Carvin, of Landport, in the County of Hants,
for the Invention of "IMPROVEMENTS IN SCREW PROPELLERS."
Sealed the 10th February 1868, and dated the 15th August 1862.
PROVISIONAL SPECIFICATION left by the said Thomas Carvin at the
Office of the Commissioners of Patents, with his Petition, on the 15th
August 1862.
I, THOMAS CARVIN, of Landport, in the County of Hants, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN SCREW PRO-
PELLERS," to be as follows:-
This Invention consists of certain improvements in screw propellers, whereby
the pitch of the blades may be more readily adjusted and fixed than by the
methods at present in use, and by the application of which to vessels a greater
speed can be obtained than by the ordinary propellers.
I propose to form the blades of the propellers of an irregular oval outline,
the blades being bent or bowed so as to form a curvilinear surface to act upon
the body of water in contact therewith, whereby the water may be gradually
and easily displaced, and the vessel propelled without any sensible vibration
being caused by the propeller.
I propose in some cases to extend or prolong the extremities of the blades
so as to form their outline of an elongated irregular oval.
The blades are to be fixed in metal heads or nuts having a number of

page_text: angles or faces thereon, in order that they may be inserted into corresponding
recesses or sockets in the boss at any required pitch. The angular bearings
or faces prevent any alteration in the pitch of the blades when once adjusted in
the boss. The faces of the nuts in which the blades are inserted should each
be provided with a recess or female screw, in order that a pin, bolt, or screw
may enter therein through the exterior of the boss, whereby the blades will be
firmly retained in the sockets. It is thus evident that the pitch of the blades
may be easily changed, and that their position, when once adjusted, cannot
accidentally be varied.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Carvin in the Great Seal Patent Office on the
14th February 1863.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
CARVIN, of Landport, in the County of Hants, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fifteenth day of August, in the year of our Lord
One thousand eight hundred and sixty-two, in the twenty-sixth year
of Her reign, did, for Herself, Her heirs and successors, give and grant
unto me, the said Thomas Carvin, Her special licence that I, the said
Thomas Carvin, my executors, administrators, and assigns, or such others
as I, the said
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 law-
fully might make, use, exercise, and vend, within the United Kingdom of
Great Britain and Ireland, the Channel Islands, and Isle of Man, an Inven-
tion for "IMPROVEMENTS IN SCREW PROPELLERS," upon the condition (amongst
others) that I, the said Thomas Carvin, 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 Thomas Carvin, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement:―

page_text: This Invention consists of certain improvements in screw propellers, whereby
the pitch of the blades may be more readily adjusted and fixed than by the
methods at present in use, and by the application of which to vessels a greater
speed can be obtained than by the ordinary propellers.
I form the blades of the propellers of an irregular oval outline, the blades
being bent or bowed so as to form a curvilinear surface to act upon the body
of water in contact therewith, whereby the water may be gradually and easily
displaced, and the vessel propelled without any sensible vibration being caused
by the propeller.
In some cases I prolong or extend the extremities of the blades so as to
form their outline of an elongated irregular oval.
In order that my said Invention may be more completely understood,
I now proceed to describe the best means I am acquainted with for carrying
the same into practical effect, reference being had to the accompanying Sheet
of illustrative Drawings, and to the numeral figures and letters of reference
marked thereon respectively, as follows, similar letters denoting corresponding

page_text: removal and re-insertion of the blades in the required position and securing
them to the boss by means of screw bolts.
Having now described the nature of my said Invention, and the manner
in which the same is to be performed, I would remark in conclusion that I do
not limit myself to the exact details I have expressed, as the same may
obviously be varied or modified without in any way departing from the
principles on which my Invention is based; but what I claim as my Invention,
and desire to be secured to me by the herein in part recited Letters Patent, are,
the "Improvements in Screw Propellers," consisting of the form shewn in the
Drawings annexed, whereby the action of the wings of a bird is brought to
bear upon the water, throwing off the water into the apex of a cone instead of
in a cylindrical form, thus greatly diminishing the slip of the screw, and
causing it to acquire increased propelling power, substantially as herein
specified and illustrated.
In witness whereof, I, the said Thomas Carvin, have hereunto set
my hand and seal, this Twelfth day of February, One thousand
eight hundred and sixty-three.
Witness,
JOHN SHATTOCK SIMONS,
17, Gloucester St., Portsea.
THOMAS CARVIN. (L.S.)