A COMBINED COMPASS AND COURSE CORRECTOR FOR SHIPS
Year: 1885

page_text: I, RICHARD HENRY TURNER PLUMB, of Bridge Crescent, Sunderland in the
County of Durham Nautical Optician, do hereby declare the nature of the said
invention for "A COMBINED COMPASS AND COURSE CORRECTOR FOR SHIPS" to be
as follows:-
This invention relates to improvements in ships standard compasses, or compasses
used as standard compasses, by the adaptation of a compass corrector as herein-
after described, to the compass itself, or in some cases to the "binnacle" and which
at all times, when in use, shall correctly indicate the course of the ship or vessel
upon which it is applied, either the true course or the magnetic course as may be
desired.
The instrument consists of an annular ring, with the points of the compass
inscribed thereon; but in the reverse manner to that upon which it is at present
constructed; that is to say, if an ordinary compass dial were laid upside down
North and South would occupy the same positions but the East and West and all
intermediate points would be exactly reversed.
Outside of this is another annular ring marked in degrees, and a variation arc
inscribed in degrees also, but only as far as 45°, on either side of "ships head."
These are fixed on the top of the compass (or it may be on top of binnacle) in such
a manner as that each can be revolved independently of the compass or binnacle
and of each other, or can be made steadfast by the aid of clampscrews. The sight
arrangement consists of a crossbar one end terminating in a pointer and working
on a boss in the centre of the compass. On this are fixed the sights, a short closed
sight and a long open one with wire and mirror backshade.
These fold down on to the crossbar when not in use. It is also fitted with a
"shadow-style," which may be used with or without the sights.
In using the instrument put the meridian of graduated circle to "ships-head"
find the sun's true bearing by azimuth tables, such as Burdwoods, and put the
South point of the compass dial thereon, turn the crossbar round until the shadow
of the wire in open sight-vane falls upon the slit in closed sight-vane, and the
pointer indicates the true course,

page_text: To find the magnetic course allow easterly variation to the right and westerly
variation to the left and proceed as before.
To find the course by any object of known bearing, such as stars, lights, &c,
place the said bearing on "ships-head" then cut the bearing with the sight-vanes,
and the pointer indicates the course.
The adaptation of this corrector to the compass or binnacle itself makes a most
perfect combined instrument and effects an economy in the first cost, as instead of
having to buy two distinct and separate instruments, you need only have the one.
It also prevents the inaccuracies which frequently occur in comparing the compass
with a distinct and separate instrument.

page_text: A Combined Compass and Course Corrector for Ships.
>
I RICHARD HENBY TURNER PLUMB, of Bridge Crescent, Sunderland in the
County of Durham Nautical Optician do hereby declare the nature of the said
invention and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement:-
This invention relates to improvements. in ships standard compasses or compasses
used as standard compasses, by the adaptation of a compass corrector as hereinafter
described, to the compass itself or in some cases to the "binnacle" and which at all
times, when in use, shall correctly indicate the course of the ship or vessel upon
which it is applied either the true course or the magnetic course as may be desired.
The instrument consists of an annular ring, with the points of the compass
inscribed thereon, but in the reverse manner to that upon which it is at present
constructed; that is to say, if an ordinary compass dial were laid upside down,
North and South would occupy the same positions but the East and West and all
intermediate points would be exactly reversed.
Outside of this are another annular ring marked in degrees, and a variation arc
inscribed in degrees also, but only as far as 30° to 45°, on either side of "ships head."
These rings are fixed on the top of the compass (or it may be on top of binnacle)
in such a manner as that each can be revolved independently of the compass or
binnacle and of each other, or can be made steadfast by the aid of clamp screws.
The sight arrangement consists of a crossbar one end terminating in a pointer and
working on a boss in the centre of the compass. On this are fixed the sights, a
short closed sight and a long open one with wire and mirror backshade.
These fold down on to the crossbar when not in use. It is also fitted with a
"shadow-style" which may be used with or without the sights.
DESCRIPTION OF DRAWINGS.
The accompanying sheet of drawings shows my invention applied to a liquid or
spirit compass, and fitted to the compass itself but it is obviously adapted for use
with any compass or to be fitted to the binnacle immediately above the compass."
Figure 1 is a vertical section through the compass and figure 2 a plan on top.
The compass bowl hung in a "Gimbal" ring balanced with lead, card with
magnetic needles air globe with jewel mount for needle air chamber and glass fitted
on lip ring by the "Bezil" ring are all as in an ordinary spirit or liquid compass.
A is the lip or shoulder ring on compass bowl. B the "Bezil" ring which secures
the glass and upon which is fitted, so as to revolve upon it, the annular ring C
which is marked in degrees on outer circle. Within a sunk portion of inner
circumference of C is fitted another annular ring D which can be revolved with C
or independently of it by the knobs E when the set screws F are slackened. This
ring D forms the inverted or reversed compass dial having N and S points
corresponding with the compass card but E and W, and all intermediate points,
reversed-G is the variation are marked 30° on each side of a point which
indicates the direction of ship's head and this arc is carried upon one of the

page_text: "
'journals" which support the compass in the "gimbal " ring. H is the crossbar
centred freely on the boss J, cemented on the glass and fitted at one end with the
hinged closed sight vane K with sliding coloured sun shade L. M is the hinged
open sight with wire fixed in it and fitted with a hinged mirror back-shade N
adjustable to any angle. The opposite end of crossbar H forms the pointer P.
When the sights and crossbar are not required they are removed and a shadow
pin fits into a socket in the boss J. as shewn by dotted lines.
When the course corrector is applied to the binnacle. a casting is fitted to the
dome equivalent to the "bezil" ring B and the annular rings C and D work
thereon in the same manner, the crossbar H and sights K and M being carried on
a boss cemented to the glass in dome of binnacle.
In using the instrument put the meridian of graduated circle C to "ships-head,"
find the suns true bearing by azimuth tables, such as Burdwoods, and put the
South point of the reversed compass dial D thereon, turn the crossbar H round
until the shadow of the wire in open sight vane M falls upon the slit in the closed
sight vane K and upon the centre line of crossbar. The pointer will now indicate
the true course.
To find the magnetic course allow easterly variation to the right and westerly
variation to the left and proceed as before.
To find the course by any object of known bearing, such as atars, lights &c, place
the said bearing bearing on line of ship's head, then cut the bearing with the sight
vanes K and M and the pointer indicates the course.
When the suns rays are not strong enough to throw a shadow look through the
closed sight vane K and cut the suns disc with wire of open sight M the pointer
now indicates the course.
The adaptation of the corrector to the compass or binnacle itself makes a most
perfect combined instrument and effects an economy in the first cost, as instead of
having to buy two distinct and separate instruments you need only have the one.
It also prevents the inaccuracies which frequently occur in comparing the compass
with a distinct and separate instrument.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is
-
The adaptation and application to a compass, or to the binnacle of a course
corrector constructed and operating as described or so modified as to give
equivalent results—the compass and course corrector combined forming a standard
or azimuth compass and course corrector in one instrument, dispensing- entirely
with a separate course corrector and insuring greater accuracy-no time being lost
in comparing both compass and course corrector being sighted simultaneously
and the course being read' off without reversing substantially as described and
shewn.
D
3
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7000