An Apparatus for Ascertaining the Position of a Ship at Sea from the Deadreckoning.
Year: 1894

page_text: Date of Application, 18th July, 1894
Complete Specification Left, 18th Apr., 1895-Accepted, 17th Aug., 1895
PROVISIONAL SPECIFICATION.
An Apparatus for Ascertaining the Position of a Ship at Sea from
the Deadreckoning.
1 SAMUEL CAREY of No. 1 Overhill Kingswear in the County of Devon
Yacht Master do hereby declare the nature of this invention to be as follows:-
The apparatus consists of a graduated quadrant of a circle, the radii at the ends
of the quadrant being also graduated. Pivotted at the centre is a graduated arm
also carrying a slide to which a second graduated arm is pivotted.
Dated the 13th day of August 1894.
An Apparatus for Ascertaining the rositION
One Deadreckoning.
I SAMUEL CAREY of No. 1 Overhill Kingswear in the County of Devon
Yacht Master do hereby declare the nature of this invention and in what manner
the same is to be performed, to be particularly described and ascertained in and by
the following statement :-
The invention refers to an apparatus intended to be used for ascertaining the
position and place on a chart, of a ship at sea, and the said apparatus consists of a
graduated quadrant of a circle the radii at the ends of the quadrant being also
graduated.
'
Pivotted at the centre is a graduated arm also carrying a slide to which a
second graduated arm is pivotted.
The invention is shown in the annexed drawing Fig. 1 in which D. is the
quadrant of a circle graduated as thereon represented A B and C D being the
radii thereof also graduated.
E F is an arm pivotted at E and graduated as represented.
G. H. is an arm pivotted at G on a slide affixed to arm E F and graduated as
represented.
From the above description of the apparatus or appliance it will be understood
that the instrument or apparatus comprises or consists of a plate of brass tin or
other metal or of cardboard whereon is drawn the fourth part of a circle which
fourth part of a circle is divided on each side thereof into 90 parts and each part
or division is numbered in tens from 0 to 90 as in the annexed drawing is shown.
These parts or divisions each represent 90 miles. They also represent the
90 parallels of latitude from the pole to the equator. The nine curved lines running
from one side to the other at equal distances appart represent 9 parallels of
latitude. The arc of the quarter circle is divided between A & D into 90 degrees.
An arm is pivotted at E, (which arm is also made of brass, tin, or other metal or
of cardboard) and is divided into 90 parts or divisions, which parts are numbered in
tens from 0 to 90. This arm carries a slide to which a second graduated arm is
pivotted, which arm is divided into 50 parts and numbered in teus from 0 to 50.
The manner in which the instrument is used is as follows:-
The person using it must know the course of the ship and the distance she has

page_text: sailed from her place of departure; both of which will be ascertained in the usual
way by deadreckoning: Having done this the user will then proceed as follows:-
He places the instrument in front of him and moves the arm E. F. until the
centre thereof is over the number in the arc which represents the ships course (the
course of a ship is always calculated in degrees, and the arc of the instrument as
will be seen on reference to the drawing is numbered to represent degrees that
is:-5, 10, 15, 20, &c.). He will then move the sliding arm G. H, until the upper
edge thereof is in the centre of the division of the column A. B. which represents
the distance the ship has sailed from her place of departure (this distance is
calculated in miles and every division of column A. B. represents one mile). The
sliding arm G. H. when so placed should lie across column A. B, and should form
right angles with the said column A. B.
The division of the sliding arm G. H. (counting the divisions from G.) which is
over the division of column A. B. will be the difference of latitude which the ship
has made. As the latitude of the place of departure is known by the person
navigating the ship, all he has to do, after finding the difference of latitude as
above explained by this instrument is to mark such difference on the chart.
When the course sailed exceeds 4 points the column C. D. will be used instead
of A. B.
The method at present in use for finding the difference of latitude involves the
use of books and printed. tables, which are both cumbersome and intricate, and
which cannot be used upon the deck of a ship in rough weather, by this invention
a ready means is provided of finding the difference of latitude, and therefor the
position of the ship at any time without books or tables, and without reference to
the state of the weather.
Having now particularly described the nature of my said invention and in what
manner the same is to be performed I declare that what I claim is :-
An instrument consisting of a graduated quadrant of a circle the radii at the
ends of the quadrant being also graduated and with a graduated arm pivotted at
the centre which graduated arm also carries a slide to which a second graduated
arm is pivotted which on being manipulated as set forth above will give the position
of a ship at sea from one deadreckoning all constructed arranged and acting
substantially as hereinbefore described and illustrated with reference to the
accompanying diagram together with any mere modifications thereof.
Dated this 14th day of August 1895.
R. G. WINTER,
Agent for the said Samuel Carey.