A New or Improved Instrument for Observing and Laying Off the Bearings of Vessels at Sea and similar purposes.
Year: 1892

page_text: Date of Application, 25th Aug., 1892
Complete Specification Left, 22nd Feb., 1893-Accepted, 8th Apr., 1893
PROVISIONAL SPECIFICATION
A New or Improved Instrument for Observing and Laying Off the
Bearings of Vessels at Sea and similar purposes.
SAMUEL MAXWELL WEST CROSKERY Master Mariner 20 Highfield Crescent
Rockferry Cheshire do hereby declare the nature of this invention to be as
follows:-
arm.
An improved ships "position finder" composed of a circle and marked as a
compass, fitted with three movable arms; each of which are slotted in the center
and have light wire hair lines fitted exectly in the middle of each slot. In the
center of the circle is a movable sight vane or pin, and also one on the end of each
The arms are fitted with clamping screws for setting them as a fixture in any
position. In using it, the bearings can be taken by holding it horizontally; or it
can be rested on the compass top or a light wooden stand made for the purpose.
Three objects or points of land are sellected and the sight vane on each arm brought
in a line with the object taken and the center style. Thus taking three objects.
The instrument is then placed on the chart and moved untill the hair lines in the
slots are exectly on the points taken. Then remove the center pin, turn it and
press the sharp end in to the small hole in the center, so marking the chart, which
will be the ships exact position.
Dated this 24th day of August 1802
SAMUEL MAXWELL WEST CROSKERY.
COMPLETE SPECIFICATION.
A New or Improved Instrument for Observing and Laying Off the
Bearings of Vessels at Sea and similar purposes.
I, SAMUEL MAXWELL WEST CROSKERY, of 20 Highfield Crescent, Rockferry,
in the County of Cheshire, Master Mariner, 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 :-
An improved ships "position finder" composed of a circle and marked as a
compass fitted with three movable arms, each of which are slotted in the centre
and have light wire hair lines fitted exactly in the middle of each slot. In the
centre of the circle is a movable sight vane or pin, and also one on the end of
each arm.
The arms are fitted with clamping screws, for setting them as a fixture in any
position. In using it the bearings can be taken by holding it horizontally or it can
be rested on the compass top or a light wooden stand made for the purpose. Three
objects or points of land are selected and the sight vane on each arm brought in a
line with the object taken and the centre style. Thus taking three objects. The
instrument is then placed on the chart, after having removed the centre pin, and
moved until the hair lines in the slots are exactly on the points taken. Then press
the sharp end in to the small hole in the centre, so marking the chart, which will be
the ships exact position.
And in order that my said invention may be the better understood I will proceed
to explain the same with reference to the accompanying sheet of drawings in
which:-
Figure 1 represents a plan of an instrument for observing and laying off the
position of vessels at sea and similar purposes constructed according to this
invention

page_text: Figure 2 is a three legged compass for use with the same.
a is a circle of metal or other suitable material marked as a mariners compass,
b is cross arm to which are pivoted the arms adj each arm is slotted down the
centre and is fitted with fine wires g, exactly in the centre of each slot, is a
movable sight pin fitted to the centre of the circle a and projecting through the
same, the projecting portion terminating in a point.
Each arm has at its outer end a similar sight pin j screwed into a tapped hole at
the end of the arm, and has also a clamping screw K to clamp it to the circle a in
any desired position. The arms c d f may be made telescopic if desired for use
with large scale charts.
When it is desired to take the bearings of a vessel at sea the instrument is held
horizontally or rested. on any convenient object for example a light wooden stand
made for the purpose.
Three objects or points are selected and the sight pin on each arm brought into
line with the objects and the centre pin each arm being sighted to a different
object.
The arms are then clamped to the circle and the instrument placed on the chart
after removing the centre pin, and, moved about till the wires in the slots are
exactly over the points or objects taken. The centre pin is then pressed into the
hole in the centre of the circle and a mark made on the chart which mark will
indicate the ships exact position.
When however the objects sighted come under the circle or are too close to the
centre of the instrument when placed on the chart it will be necessary to make use
of the three legged compass or pointer shewn at Figure 2 in the following manner.
After the objects are sighted and the arms clamped to the divided circle the
three legged pointer is dropped over the centre pin of the instrument a hole y
being provided in the pivot thereof for this purpose and the points extended till
they rest in the crutches outside the clamping screws in which position they
coincide with the indices on the movable arms the compasses are then placed on
the chart and moved until the legs thereof are over the positions thereon of the
objects chosen the centre pin of the instrument is then passed through the hole y in
the small compass and the position of the vessel marked on the chart as before.
Or the small compasses may be placed in position before the objects are sighted
and when the legs rest in the crutches n they will move round the divided circle
with the arms, when the objects are sighted they are removed and laid on the chart
and the ships position marked off as hereinbefore described.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
.claim is
1st. In an instrument for observing and laying off the bearings of vessels at sea.
and similar purposes the combination of a divided circle marked with the points of
the compass with three or more arms pivoted thereto each arm being provided with
slots having a hair wire in the centre of the same and sighting pins or vanes at the
centre of the said circle and outer end of the arms all substantially as described and
shewn by the accompanying drawing and operated in the manner specified.
2nd. In an instrument for observing and laying off the bearings of vessels at sea
and similar purposes the three legged compass or pointer shewn at Figure 2 as and
for the purpose stated.
Dated this 22nd day of February 1893.
FREDK. WALKER,
11, Furnival Street, Holborn, London, E.C., Agent for he Applicant.