Year: 1896

page_text: Date of Application, 14th Feb., 1896-Accepted, 11th Apr., 1896
Fig. 1. shows a view of my improved contrivance set for laying off a ship's course..
Fig. 2. shows my invention with extra pointer and pin to act as a station pointer
for finding the position of a ship.
Fig. 3. shows a view of transparent quadrant, to be used for the purpose of
showing a magnetic course, from a true course, or by knowing the compass error,.
to give the compass course.
Fig. 4. is a view of pointer with enlarged lug with hole in it to receive pivot.
Fig. 5. is view of Fig. 2. looking in at bottom end.
For the purpose of my invention I employ a long loose rule A which may be
transparent if desired. Upon the rule A I place
Upon the rule AI place a loose slide B provided with
flanges C for overlapping the sides of the said rule to allow of it being slid along
without slipping off this slide fitting the rule but loosely enough to allow it to slide
without shaking, a screw D passes through the slide B, the head of such screw fitting
into a countersunk hole in the underside of the slide, on the top of the said slide
I place a pointer E which is attached to the screw D and operated by it, this pointer
has a lug F at its pivotted end in which is a hole for the pivot or screw D to pass
through, to allow of the centre being in a direct line with the edge of the rule, and
on the top of the said rule E, I place a mariners compass or circle of degrees G,
the screw passes through this also and acts as a pivot for the mariners compass G
to turn on the rule E being a fixture to the screw D turns with such screw both the
mariners compass G and the rule E may be clipped or held by means of a thumb-
screw or the like H on the said screw D. On either end of the slide B I form a
raised part J having a line K on it called the lubber line or ship's head.
When the contrivance has to be used as a station pointer for giving the position
of the ship see (Fig. 2,) the screw or pivot D has a hole drilled through to receive
a pin L, and the rule A is transparent and is provided with a line M, down the
centre, holes N being formed at suitable distances apart on this line, the slide also
having a clip O and screw P for binding or holding the mariners compass firm.
I also employ an extra transparent pointer R with a line S all its length down
the centre, and a hole at the bottom end, this pointer is placed on the top of the
mariners compass, the screw D passing through the hole and acting as the pivot
for it to turn on, the thumbscrew on the top can be used for holding the whole lot
Price 81

page_text: firm and thus prevent them from turning. The variation scale shown at Fig. 5 is
employed for the purpose of correcting a true course into a magnetic one.
This scale consists of a transparent piece of material with the degrees of
variation marked off on it and is placed on the screw D above the mariners compass
on which it revolves. In using a true chart or moving the compass pointer on to a
line of latitude or longitude the true course is given. To correct a true course into
a magnetic course revolve the scale of variation (without the amount of degrees of
variation) on to the true course, the line of zero on the scale of variation then cuts
the magnetic course.
When using the instrument to lay off ships course, place either edge of the long
rule A. from known position of ship to desired position, slide the compass rule or
pointer E along the long rule A to the nearest compass on chart, until either edge
comes on the N. and S. line, clamp the compass card G, on the inside edge of the
compass rule, or pointer E, the course marked off on the compass card by the ship's
head or lubberline is the course to be steered.
To use the instrument as a station pointer :-
The ship being off the land, the navigator takes the angular bearings or distances
of prominent land marks or objects which can be seen from the ship by the aid of
the compass, sextant, or other instrument which will give these angles, these angles
or bearings are set off on the compass card G or the chart rule by the three
legs A E and R which are now all acting as pointers of a position finder. The
station pointer or rule is then moved on the chart until the pointers come into their
respective land marks or objects, the pin L passing through the centre of the
instrument or through the screw D pricks the chart, this marking is the position
required and is the ship's position.
Having now particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed I declare that what I
claim is :-
1. An instrument consisting of a transparent or other rule A, having a slide B,
with rule or pointer E, and mariners compass G working upon screw or stud D,
with binding screw H, lubber lines J, with or without variation scale, in the
manner and for the purposes substantially as shown and described, see Fig. 1.
2. An instrument consisting of a rule A, having centre line M, with holes N,
slide B, rule or pointer E, mariners compass G transparent pointer R, having
centre line S, clip O and screw P, pivot or screw D with thumbscrew H, in the
manner and for the purposes substantially as shown and described.
3. An instrument for giving a ships course, finding a ships position, or for setting
off or ascertaining angles constructed in the manner substantially as described.
Dated this Thirteenth day of February 1896.
JOHN E. WALSH,
Savile Street, Hull, and Crossley Street, Halifax,
Patent Agent for the Applicant.