Improvements in Azimuth Indicators, and in Ships' Compasses for their use therewith.
Year: 1891

page_text: Date of Application, 26th Feb., 1891
Complete Specification Left, 24th Apr., 1891-Accepted, 6th June, 1891
PROVISIONAL SPECIFICATION.
Improvements in Azimuth Indicators, and in Ships' Compasses for
their use therewith.
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 instruments for obtaining azimeters or bearings of any
objects to be used either in connection with a ship's compass or otherwise.
My invention has for its object the special construction and arrangement of
parts of such an instrument that an azimuth or bearing may be obtained with
greater accuracy and increased facility either by day or night than in ordinary
instruments thereby obviating many disadvantages in the same.
These disadvantages may be summarised as follows:-
As the sight and dial arrangements are rigidly attached to one another the
whole being supported on gimbals and weighted so as to maintain a horizontal
position, considerable unsteadiness of the dial may be occasioned owing to the
action of the wind on the surface thereof or by the movements of the observer's
hand in manipulating the instrument.
These movements cause the dial or compass to be put out of the horizontal plane
and the sight or indicator to be out of the vertical.
Considerable difficulty is also experienced in illuminating the dial or scale, as
the glare of light from lamps at present used prevents the observer from seeing
stars or other objects at night, this defect I entirely obviate by my invention.
The whole instrument as made according to my invention is covered in and
protected from wind or weather, and is much lighter, more compact and occupies
less room whereby it may be placed with greater convenience in any part of the
vessel.
I carry out my invention as follows:-
Upon the verge of the compass or dial I arrange one or more supports preferably 4
so that they form a frame or support to a ring directly over the compass or dial
of the azimuth indicator. This ring may or may not be graduated in degrees or
other divisions to correspond with the divisions on a ring placed around the compass
or with those on the azimuth dial.
The supporting frame is capable of movement about the vertical centre line of
the instrument.
In the upper ring I place or fix a sight or mirror with the usual dark shades the
whole being suspended on gimbals and having a weight at its lower part so as to
This sight
maintain it in a vertical position irrespective of exterior movement.
presents very little surface to the wind also the weight has a greater mechanical
advantage over the surface exposed than in ordinary instruments, so that the wind
will cause little or no deviation from the vertical.
The sighting arrangement can be supported in the framework which may form
part of the binnacle of the ship's compass or it may fit, upon a framework supported
on a stand or stands of special construction situated in different parts of the
vessel.
This stand consists of a hollow hemisphere or bowl mounted on a standard of
suitable height.
Or the instrument may be mounted and used in a wooden or metal case so as to
be moved about and placed in any part of the ship as required.
This hemisphere is made with its interior surface of a reflective nature such as
white enamel.

page_text: Upon the upper part of the hemisphere of metal or other material a verge is
supported carrying a glass cover.
This verge is adapted to be turned round upon its support and the glass cover
has a centre line cut or engraved upon it diametrically, for the purpose of
indicating the line of bearing. A small piece of ground or opal glass is arranged
with an index line or mark and bearing the words " Ship's Head."
This plate is to indicate the exact position of the ship's head.
Under and upon the glass cover is supported an opal glass dial or dial of other
translucent material which is divided as usual, the method of support is by means
of a clamp screw attached to the opal dial which passes through the glass cover,
and is supported and locked thereto by a thumb piece and locknut. It can thus be
fixed to the glass cover or if necessary the screw can be slacked and the dial
lowered upon a pointed or coned support situated in the interior of the hemisphere.
By these means it is obvious that the dial may be set and fixed in relation to the
bearing line on the glass cover, or in relation to the ship's head as the circumstances
may desire. A. lamp is situated on the side of the hemisphere or frame, or an
electric lamp may be placed therein so as to illuminate the interior and thus the
opal glass dial and plate bearing the inscription "ship's head." I may also place
or suspend in this upper ring (if desired) an hour circle mounted so as to be set to
any latitude North and South and fitted with a sight which can be set to the
apparent time at the ship so as to show the ship's true course without calculation
or the use of tables. The method of using my improved instrument which I call
"Azimeter" is as follows:-
an
The azimeter as above described either on the stand, compass, or in a movable
box is placed in position in relation to the vessel with the index mark "ship's head
exactly fixed towards the ship's head so that if the diameter or bearing line on the
glass cover of the upper verge is set to this index mark this said line will be in the
line of, or parallel to the ship's keel. This being done the instrument is used in
the same way as the ordinary pelorus viz.: as follows:-
To find the true course the ship is on? Revolve the compass dial by the thumb-
head until the azimuth or true bearing of the object observed is set to the bearing
line on the glass cover of the upper verge.
After having clamped the dial by means of a lock nut revolve the upper verge
and dial together until the object bears through the sights or is reflected on the
centre line of the mirror the true course is then shown at the ship's head mark.
To place the ship on any course required?
Set the division of the dial plate indicating the required course to the sliip's head
mark unclamp and slacken the thumb screw so that the dial rests upon the
supporting pin within the casing. Then revolve the upper verge with the sights
until the diameter or bearing line on the glass lies over or coincides with the true
bearing of the object to be observed. The vessel being now swung round until the
object bears through the sight or is reflected on the centre line of the mirror is
then on the course required.
To take compass bearings by the azimeter ?
Set the compass dial with the ship's course (as shown by the ship's standard
compass) to the ship's head then by revolving the upper verge the diameter or
bearing line indicates the compass bearing of all objects observed through the sights
or in the mirror.
To measure angles from the ship's head or between two or more objects; set the
compass dial with its north point to the ship's head mark, then revolve the upper
verge, and the diameter or bearing line on the glass cover shows the angles of all
objects observed from the ship's head and the differences in their readings are the
angles between them.
may arrange an ivory plate at the back or reversed side of the azimuth mirror
having a centre line marked so that bearings of the sun can be obtained by the
shadow of the sight line or wire upon it in the usual manner. A small spirit level
is fixed upon the sight to show that it is swinging level. A clinometer can be

page_text: attached if desired to the azimeter to indicate the heel of the vessel at the time of
observation. The lamp for illuminating the dial can be fitted with a shutter for
obscuring the light entirely if required so as to only illuminate it at the moment it
is desired to read off the readings.
The instrument is made so that any number of pillars or stands can be fixed in
various convenient places on board the ship and the instrument can be shifted from
one to another as required. And where these stands are not placed so as to affect
the compass they can be made of iron thereby reducing the cost thereof. In using
the azimeter with the standard or other compass of a ship the swinging sight or
mirror is mounted so as to revolve in the upper ring, this ring being divided in
degrees and figures from 0 at the ship's head to 180 either way. A similarly
divided and figured ring is fitted within the inside of the compass bowl concentric
to the compass card. By these means the angle of the observed object from the
ship's head is read off on the upper divided ring, and the observer casting his eye
down to the corresponding division on the lower divided ring in the compass bowl
reads the exact compass bearing on the object.
Dated this 26th day of February 1891.
FELL & WILDING,
1, Queen Victoria Street, London, E.C., Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Azimuth Indicators, and in Ships' Compasses for
their use therewith.
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 instruments for obtaining azimuths or bearings of any
objects to be used either in connection with a ship's compass or otherwise.
My invention has for its object the special construction and arrangement of parts
of such an instrument that the azimuth or bearings may be obtained with greater
accuracy and increased facility either by day or night than in ordinary instruments
by obviating many disadvantages in the same.
These disadvantages may be summarised as follows:-
As the sight and dial arrangement are rigidly attached to one another, the dial
being supported by gimbals and weighted so as to maintain a horizontal position,
considerable unsteadiness of the dial may be occasioned owing to the action of the
wind on the surface thereof or by the movement of the observer's hand in manipu-
lating the instrument.
This movement causes the dial or compass to be put out of the horizontal plane
and the sight or indicator to be put out of the vertical.
Considerable difficulty is also experienced in illuminating the dial or scale as the
glare of light from lamps at the present used prevents the observer from seeing stars
or other objects at night.
This difficulty I entirely obviate by my invention. The whole instrument as
made according to my invention can be covered in and protected from wind or
weather, and is much lighter, more compact, and occupies less room, whereby it
may be placed with greater convenience in any part of the vessel.
In order that my invention may be the better understood, I now proceed to
describe the same in relation to the drawings hereunto annexed reference being had
to the figures and letters marked thereon, like letters refer to like parts in the
various figures.
Fig. 1. is a sectional view of my improved azimuth indicator arranged in
connection with a pelorus, or dumb azimuth dial.

page_text: ig. 2 is a side view of the upper part of the instrument.
Fig. 3 is a plan of Fig. 2.
Fig. 4 is a view of the indicating arrangement seen from below.
Fig. 5 is a side view of the same.
Fig. 6 is a view of the upper part of the indicator with the telescope attached.
Fig. 7 is an enlarged view of the sights of the indicator.
Fig. 8 is a plan of the pelorus or dumb azimuth dial in its bowl or case.
Fig. 9 is a cover for placing over the sighting device when not being used.
I carry out my invention as follows:-"
Upon the verge A of the ship's compass or dumb azimuth dial carried within the
bowl BI arrange one or more supports C preferably four in number so that they
form a frame or support for a ring D, situated directly over the compass or dial E
of the azimuth indicator.
This ring D may be, if desired, graduated into degrees or other divisions to
correspond with the divisions on the ring placed around the compass, or with those
on the azimuth dial E as hereafter more fully described.
The supporting frame as shewn in Fig.
is capable of movement about the
vertical centre line of the instrument and may be attached to the frame in order to
allow such movement by screws a which are inserted into the exterior casing or
verge A and screwed through and engage with the slot situated upon the interior
framework around which the verge A is situated.
In the upper ring 1 arrange a sight or mirror F with the usual dark shailes of
the ordinary, construction and mount the same in gimbal rings ff (Fig. 4), and
attach a weight e at the lower part so as to maintain the whole of the indicating
device Fin a vertical position irrespective of movement of the whole apparatus.
This arrangement of the sight presents very little surface to the wind, and the
weight has a greater mechanical advantage over the surface exposed than in
the ordinary instruments so that the wind will cause little or no deviation of the
indicating device from the vertical. The ring D engages upon steady pins dd
situated upon the plate H this plate has two circular segmental slots one through
which the jamming screw passes for rigidly attaching the plate H to the ring D,
and the other through which the zero mark passes, this being mounted upon the
ring D.
The ring H is graduated along the slot through which the zero mark passes,
these graduations being in degrees Easterly & Westerly the object of this is to
allow for the variation or difference between magnetic North and true North in the
various observations when desirable.
It must be understood that the sighting arrangement can be supported and
constructed so as to revolve in the framework which may form part of the binnacle
of the ship's compass.
In this case the supporting frame need not revolve in its seating but is made a
fixture to the compass stand, and in consequence of this some means must be
provided whereby the movement of the sighting device can be made so as to be
definitely determined in relation to the compass card or a ring situated around the
same.
In order to effect this so that the reading of the instrument may be made with
equal facility as is done in the instrument illustrated I graduate the frame D upon
its upper face or edge so as to correspond with the divisions on a graduated ring
situated around the compass card so that the zero or ship head mark on the ring D
is exactly vertical over the zero or ship head mark on the ring around the compass
card.
When now the sighting device has been revolved till the desired position is
obtained, the magnetic bearing of the sight is obtained by reading the division of
the compass that is opposite to a division on the latter ring corresponding to the
division on the upper ring D which is opposite a zero mark on the sighting device.
The stand B of the pelorus or dumb azimuth dial as shown in Fig. 1 consists of
a hollow hemisphere or bowl B mounted upon a standard of suitable height.

page_text: white enamel or other equivalent composition.
The verge A carries a transparent cover) preferably of glass, beneath this cover
is supported by means of a screw K and thumb nut ka translucent dial L preferably
of opal glass which is divided in the usual manner.
A centre line is cut or engraved diametrically across the transparent cover J or
equivalently a wire is supported diametrically across and just above the glass dial L
for the purpose of indicating the line of bearing.
I prefer to use a wire as being in closer proximity to the dial than the line upon
the glass cover, the reading is more accurate.
Upon the ring a I arrange a small piece of translucent material such as opal
glass having an index line or mark and bearing the words "Ship's Head."
This plate is to indicate the exact position of the ship's head and the instrument
is adjusted so that a diametrical line coinciding with the ship's head mark shall be
parallel with the keel.
The clamp screw K has a milled head to it by which the opal glass dial L can
be rotated.
This dial may be fixed to the glass cover J by screwing up the thumb nut k so
that the dial is moved about the centre of the instrument with the sighting
arrangement F and the supporting frame.
If on the other hand the thumb nut k is slacked back so that the dial shall rest
upon a supporting pin carried by the lower cover of glass the opal dial L will
remain in a fixed position in relation to the ring a' while the sighting arrangement F
and supporting frame is being rotated.
In other words the dial may be set and fixed in relation to the bearing line
on the glass cover or in relation to the ship's head as the circumstances may
desire.
Within the bowl or upon the side of it I arrange a lamp M preferably an electric
lamp having a storage battery attached or connected with the ship's electric light
installation so as to illuminate the interior of the bowl B and thus the opal glass
dial Land the plate on the ring a' bearing the inscription "ship's head."
The upper part of the instrument carrying the ring a' may be adjusted in relation
to its bowl B by means of screws N N passing through slots n in the side of the
bowl.
When the ship's head mark on the ring a¹ has been adjusted so as to be parallel
to the keel of the vessel the upper part of the instrument may be clamped on the
stand by means of screws N.
I may remove the sighting apparatus F from its upper end or support and
substitute an hour circle mounted so as to be set to any latitude North and South
and fitted with a sight which can be set to the apparent time or declination at the
ship so as to show the ship's true course without calculation or the use of tables also
as the sighting devices Fis removable it may be used upon a framework supported
on a stand or stands containing a dumb azimuth dial which may be situated in
different parts of the vessel or the indicating device may be mounted and used in a
metal or wooden case having a dumb azimuth dial with a hole in its centre into
which the ring D' of the sighting device is inserted.
The method of using my improved instrument which I call an azimeter is as
follows.
The azimeter as above described either on a stand, compass or in a moveable box
is placed in position in relation to the vessel with the index mark "ship's head"
exactly fixed towards the ship's head so that if the diameter or bearing line on the
glass cover of the upper verge is set to this index mark this said line will be in the
line of or parallel to the ship's keel. This being done the instrument is used in
the same way as the ordinary pelorus riz. as follows:-
:-
To find the true course the ship is on, revolve the compass dial by the thumb
head until the azimuth or true bearing of the object observed is set to the bearing
line on the glass cover of the upper verge after having clamped the dial by means

page_text: of the lock nut revolve the upper verge and dial together until the object bears
through the sights or is reflected on the centre line of the mirror, the true course is
then shown at the ship's head mark.
To place the ship on any course required
Set the division of the dial plate indicating the required cause to the ship's head
mark unclamp and slacken the thumb screw so that the dial rests upon the
supporting pin within the casing. Then revolve the upper verge with the sights
until the diameter or bearing line on the glass lies over or coincides with the true
bearing of the object to be observed.
The vessel being now swung round until the object bears through the sight or is
reflected on the centre line of the niirror is then on the course required.
To take compass bearings by the azimeter --Set the compass dial with the ship's
course (as shown by the ships standard compass) to the ships head then by revolving
the upper verge the diameter or bearing line indicates the compass bearing of all
objects observed through the sights or in the mirror. To measure angles from the
ships head or between two or more objects:
-
Set the compass dial with its North point to the ship's head mark, then revolve
the upper verge and the diameter or bearing line on the glass cover shows the
angles of all objects observed from the ship's head and the differences in their
readings are the angles between them.
may arrange an ivory plate at the back or reversed side of the azimuth mirror
having a centre line marked so that bearings of the sun can be obtained by the
shadow of the sight line or wire falling upon it in the usual manner.
A small spirit level is fixed upon the sight to show that it is swinging level.
A clinometer can be attached if desired to the azimeter to indicate the heel of
the vessel at the time of observation. The lamp for illuminating the dial can be
fitted with a shutter for obscuring the light entirely if required so as to only
illuminate it at the moment it is desired to read off the readings.
The instrument is made so that any number of pillars or stands can be fixed in
various convenient places on board the ship and the instrument can be lifted from
one to another as required. And where these stands are not placed so as to effect
the compass they can be made of iron thereby reducing the cost thereof.
In using the azimeter with the standard or other compass of a ship the swinging
sight or mirror is mounted so as to revolve in the upper ring, this ring being divided
in degrees and figured from 0, at the ship's head to 180 either way. A similarly
divided and figured ring is fitted within the inside of the compass bowl concentric
to the compass card. By these means the angle of the observed object from the
ship's bead is read off on the upper divided ring, and the observer casting his eye
down to the corresponding division on the lower divided ring in the compass bowl
reads the exact compass bearing of the object.
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
An improved instrument for taking azimuths or bearings of any objects consisting
of a sighting device hung so as to maintain a vertical position and mounted centrally
over or upon a compass dial or dumb azimuth dial so as to be capable of rotation in
or about in a horizontal plane with or independently of the said compass dial or
dumb azimuth dial.
2nd. In such an instrument for taking azimuths or bearings the sighting device
hung so as to maintain a vertical position in combination with a support or frame
situated centrally over the compass dial or dumb azimuth dial and carrying the
sighting device so that it may be rotated in or about in a horizontal plane thereon,
the sighting device or its support being graduated to correspond with the divisions
on the compass dial, dumb azimuth dial or a ring surrounding either substantially
as and for the purposes described.
3rd. In such an instrument for taking azimuths or bearings the sighting device
7443

page_text: hung so as to maintain a vertical position and capable of rotation in or about in a
horizontal plane in combination with a translucent dumb azimuth dial adapted to be
moved with the sighting device or otherwise as desired and a ring surrounding the
said dial having the ship's head mark upon a piece of translucent material, both the
said dial and mark being illuminated by artificial light from below substantially as
described.
4th. The construction and arrangement of an instrument for taking azimuths and
bearings of any objects substantially as described.
Dated this 24th day of April 1891.
FELL & WILDING,
1, Queen Victoria Street, London, E.C., Agents for the Applicant.