Improvements in Ships' Compasses.
Year: 1891

page_text: Date of Application, 13th Mar., 1891
Complete Specification Left, 14th Dec., 1891-Accepted, 6th Feb., 1892
PROVISIONAL SPECIFICATION.
Improvements in Ships' Compasses.
I ALEXANDER HUGHES of 59 Fenchurch Street in the City and County
of London Optician do hereby declare the nature of my invention to be as
follows:-
:-
My invention relates to ships compasses and has for its object the improved
construction mounting and arrangement of the same in relation to its adjuncts
so that its adjustment is greatly facilitated and also an improved adjustable lubber
line applied to the compass bowl or case by which the course steered may be more
accurately kept than with compasses at present in use. I carry out my invention
as follows:-
I mount the compass and case upon gimbals carried upon a frame which is
mounted on the binnacle and independent thereof, so as to be capable of turning
upon a vertical axis passing through the centre of the binnacle.
By this means the binnacle can be permanently fixed to the deck and the lubber
line of the compass case or frame afterwards adjusted accurately to the ships head
by turning the said frame about its axis until the required position or adjustment
is obtained when it may be securely fixed by one or more screws.
This is obviously more convenient and accurate than effecting the adjustment by
the holding down bolts when the binnacle is attached to the ship.
Upon this said frame I also mount the quadrantal correctors upon suitable
brackets in such a manner that the said correctors move with the frame and may
be adjusted both vertically and horizontally relative to the compass card.
I also mount the athwartship and fore and aft magnets for correcting the semi-
circular deviation, upon supports which hang from and move with the said adjust-
able frame and provide for their adjustment upon the said supports by gearing
which shall be led to a position on the binnacle so that the person adjusting the
compass can while standing in front of the binnacle and watching the motion of
the card move the magnets as required so gradually and steadily that an exact
adjustment is quickly made instead of constantly disturbing the card as is done by
moving the magnets directly by hand or shifting them from hole to hole.
This may be effected by mounting the support for carrying the magnets which
may be one or more in number so as to slide upon the said supports hanging from
the adjustable frame and arrange a screw & bevel gear or other equivalent
mechanism to effect the vertical adjustment of the magnets and their support.
The athwartship magnet or magnets for adjustment will have a separate shaft
which may be turned by means of a handle working in front of the binnacle.
The two sets of fore and aft magnets may be operated simultaneously by each
set being geared together and operated by one shaft in a similar manner to that
before described.
When the adjustable frame has been set true to the ships head the supports for
carrying the magnets may be secured to the base of the binnacle by screws or
otherwise. Also when the brackets for the quadrantal correctors are finally
adjusted in their right position they may be secured to the binnacle body by
screws.
By this construction the compass magnets and other correctors all may be
truly mounted on and attached to the adjustable frame and when the lubber line
of the compass is accurately set to the ship's head all the above are moved
together with it round a vertical axis and preserve their proper relative positions
to the compass card.
A divided scale may be attached to these supports for the magnets to indicate
at what distance below the compass card the correcting magnets are placed.

page_text: I arrange a scale around the interior of the compass case which may be
divided in any suitable number of divisions with a zero mark at the ships head.
Above this scale I arrange a sliding mark which when placed at zero is the
true lubber line.
This sliding mark may be moved by means of a rack and pinion mechanism or
in any other equivalent manner.
The objects of this marker are
1st When a course is set which is at a small division on the compass card it
is difficult for the helmsman to remember the exact bearing given him by the officer
and also to distinguish correctly the exact course required.
This disadvantage may be obviated by adjusting the movable lubber line to
a cardinal or prominent point of the compass when the ship is exactly on her
course.
2nd. Unless a person stands directly behind the compass so as to be exactly
opposite the lubber line he does not read the exact course of the ship consequently
as the helmsman stands usually on one side of the compass, he has to change from
side to side periodically in order to correct errors of observation.
To obviate this difficulty the movable lubber line is moved round to a position
directly in a line with the centre of the compass card and the helmsman.
The adjustment may be made by a detachable key which may be in charge of
the officer of the watch or the captain so that the adjustment when once set cannot
be altered.
Dated this 13th day of March 1891.
FELL & WILDING,
1, Queen Victoria Street, E.C., Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Ships' Compasses.
I, ALEXANDER HUGHES, of 59 Fenchurch Street, in the City and County of
London, Optician do hereby declare the nature of my invention and in what
manner the same is to be performed to be particularly described and ascertained
in and by the following statement :-
My invention relates to ships compasses and has for its object the improved
construction mounting and arrangement of the same in relation to its adjuncts, so
that its magnetic adjustment is greatly facilitated; and also an improved adjustable
lubber line applied to the compass bowl or case by which the course steered may
be more easily seen or read, and therefore the course desired more accurately kept
than with compasses at present in use.
In order that my invention may be the better understood I will now describe it
in relation to the drawings hereunto annexed reference being had to the letters and
figures marked thereon. Like letters refer to like parts in the various figures.
Figure 1 is a sectional elevation of a ships compass and stand having my invention
embodied therewith.
Figure 2 is a detail view of two of the magnet supports with regulating gear in
part.
Figure 3 is a plan of the upper adjustable frame which carries the compass
magnets, correctors, and gear connected therewith.
Figure 4 is a plan of the lower frame with the magnet supports in section.
Figures 5 and 6 are views of the adjustable lubber line arranged on the compass
bowl.
I mount the compass and case A upon gimbals B carried upon a frame C
which is mounted on the binnacle D and independent thereof, so as to be capable
of turning upon a vertical axis passing through the centre of the binnacle D.
By this means the binnacle D can be permanently fixed to the deck in the
ordinary way and the lubber line of the compass case afterwards adjusted

page_text: until the
accurately to the ships head by turning the frame C about its axis
required adjustment is obtained, when it may be securely fixed by one or more
screws c or other equivalent means.
Two or more of the holes through which the screws e pass, may be made elongated
to permit a certain range of movement without removing them entirely.
This method of adjustment is obviously more convenient and accurate than
effecting the adjustment by the holding down bolts when the binnacle is first
attached to the ship as has been the method heretofore adopted.
upon
Upon this said frame C I also mount the quadrantal correctors E suitable
brackets F, attaching the brackets F to the frame C by bolts through the
binnacle so that the said correctors E move with the frame C and may be adjusted
both vertically and horizontally upon their brackets F relatively to the compass
card, this being provided for by arranging longitudinal slots through which the
holding bolts and f¹ pass in the usual way.
I mount the athwartship and fore and aft magnets G for correcting the semi-
circular deviation upon carriages H which slide upon supports I which hang
from and move with the adjustable frame C, and effect the adjustment of the
position of these magnets G upon their supports I by means of gearing which
is led to a convenient position on the binnacle D for operation; so that a person
adjusting the compass can while standing in front of the binnacle and watching
the motion of the card move the magnets G as required so steadily and gradually
that an exact adjustment is quickly made, instead of the present method of
adjustment which consists of moving the magnets from hole to hole or otherwise
by hand as circumstances require, thus constantly disturbing the magnetic
equilibrium of the card to an unnecessary extent.
I carry out the means for adjustment as follows:-The carriage H carrying the
magnets G which slides upon its support I is actuated by a screwed spindle K
engaging with the lug g upon the carriage.
This spindle K carries a bevel wheel L.
In the case of the athwartship adjustment magnets this bevel wheel L is geared
with and driven by another bevel wheel K' which is mounted on a spindle / which
is led to the exterior of the binnacle or in proximity thereto so as to be operated
by means of a handle attached to the end of the spindle k.
In the case of the magnets for fore and aft adjustment, the two sets may be
operated simultaneously by each set being geared together by the shaft M carrying
bevel wheels M' M' which gear into the bevel wheels L L on each side
respectively.
This shaft carries a third bevel wheel N which gears with another bevel wheel N¹
carried on a shaft O which is also led to the exterior of the binnacle and can be
operated as heretofore described.
The lower part of each of the supports I are attached to a bottom frame Q in
order to steady them.
When the adjustable frame has been set true to the ships head, the lower frame Q
may be secured to the base of the binnacle by screws or other equivalent means,
also when the brackets for the quadrantal correctors have been finally adjusted at
their right height they may be further secured to the binnacle by screws etc.
By this construction the compass, magnets, and other correctors may be all
truly mounted on and attached to the adjustable frame C and when the lubber line
of the compass is being accurately set to the ships head, the whole of the arrange-
ments upon the frame C can be moved together with it around a vertical axis and
thus preserve their proper relative position to the compass card during adjustment.
In order that the movement of the magnets may be as steady as possible I
provide a small spring o which presses the carriage H in contact with the supports I,
so as to allow of its movement being steadily and easily effected.
The magnets G are formed with collars which engage with propelling horns h
upon the carriage H and are kept in place by a flexible retaining strap h', main-
tained in its holding position by a set screw h".

page_text: The supports I may have scales arranged upon them to indicate at what distance
the magnets are below the compass card at any specific position of the former.
I will now describe my adjustable lubber line which I illustrate in Figures 1, 5,
and 6 from which it will be seen that I arrange a scale R around the compass case A
which may be divided into any suitable number of divisions with a zero mark at
the ships head.
Above this scale R I arrange a movable zero mark S which is adapted to slide
upon the case A above the scale R a certain distance each side of the zero mark
of the scale R, and which, when placed at zero, represents the true lubber line of
the vessel.
I move this sliding mark by means of a pinion s gearing into a rack s¹ arranged
upon the plate S¹ carrying the lubber line or it may be effected in any other
equivalent manner.
The upper part of the spindle carrying the pinion is formed as a square upon
which may engage a detachable key handle or knob T for turning the spindle.
The objects of this marker are:-
1stly. That when a course is set which is at a small division on the compass card
it is difficult for the helmsman to remember the exact bearing given him by the
officer and also to distinguish correctly the exact course required.
This disadvantage may be obviated by adjusting the movable lubber line to
a cardinal or prominent point of the compass when the ship is exactly on her
course.
2ndly. That unless a person stands directly behind the compass so as to be
exactly opposite the lubber line he does not read the exact course of the ship;
consequently as the helmsman stands usually on one side of the fore and aft centre
line of the compass, he has to change from side to side periodically in order to
correct errors of observation.
To obviate this difficulty, the movable lubber line S is moved round to a position
directly in a line with the centre of the compass card and the helmsman.
When an adjustment of the lubber line has been made the detachable key T may
be removed from its spindle, and taken charge of by the officer of the watch or the
captain so that the adjustment when once set cannot be altered without the key.
Having now particularly described and ascertained the nature of my inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1st. In a ship's compass, an adjustable frame carrying the compass case, quad-
rantal correctors and correcting magnets as a complete system and independent
of the binnacle.
2nd. In a ship's compass, an adjustable frame adapted to be moved about an
axis on the binnacle carrying the compass case, and supports upon which carriages
slide carrying the correcting magnets, the said carriages being operated by gearing
led to convenient positions on the binnacle.
3rd. In a ship's compass, an adjustable frame, adapted to be moved about an
axis on the binnacle, carrying the compass case, quadrantal and other correctors,
and supports with carriages carrying the correcting magnets sliding thereon each
carriage being actuated by screwed spindles driven by gearing led to the side of
the binnacle, substantially as described.
4th. In a ship's compass a movable lubber line mark and a scale around the
compass case in combination with the compass card, substantially as described.
5th. The arrangement and construction of a ship's compass substantially as
described and illustrated in the accompanying drawings.
Dated this 14th day of December 1891.
FELL & WILDING,
1, Queen Victoria Street, London, E.C., Agents for the Applicant.