IMPROVEMENTS IN APPARATUS FOR LAYING OFF OR ASCERTAINING SHIPS' COURSES
Year: 1883

page_text: LETTERS PATENT to George Charles Lilley of Osborne Road, Finsbury Park,
in the County of Middlesex for an Invention of IMPROVEMENTS IN APPARATUS
FOR LAYING OFF OR ASCERTAINING SHIPS' COURSES
PROVISIONAL SPECIFICATION left by the said George Charles Lilley at the
Office of the Commissioners of Patents on the 28th September 1883.
GEORGE CHARLES LILLEY of Osborne Road, Finsbury Park in the County of
Middlesex, "IMPROVEMENTS IN APPARATUS FOR LAYING OFF OR ASCERTAINING
SHIPS' COURSES
"
In laying off a ship's course it has been usual to place one edge of a parallel rule
on the line joining the point denoting, on the chart, the present position of the
ship and that denoting the place for which the ship is sailing, for example the place
expected to be reached in say twenty four hours. The parallel rule is then passed
over the chart, in the usual method of operating parallel rules, to the diagram or
compass card, placed in some convenient position on the chart to denote the points
of the compass, where the direction of the line is read off. The necessary corrections
for the deviation of the inagnetic north from the true north, and of the ship's
compass are then made by calculation.
The object of this invention is to provide an instrument by which the direction
of the ship's course can be laid off without transporting the said instrument from
place to place on the chart, and by which the corrections for the deviations may be
inade mechanically instead of by calculation.
The instrument consists of a compass card mounted so as to revolve about its
centre and partially surrounded by a flat plate in the same plane (or nearly so) as
the compass card and carrying the bearing about which the card revolves. The
axis of the compass card is provided with a thumb piece on its upper side by which
it can be rotated. This axis has a small hole, (hereinafter called the centre hole),
drilled through it perpendicular to the card, passing through the centre of it, for
the purpose of ascertaining the correct position of the card on the chart. The flat
plate is provided with a straight edge preferably at a greater distance from the

page_text: centre of the card than its semi diameter. Two lines are drawn on the plate
opposite each other parallel to the straight edge and at a distance therefrom so that
a straight line joining these two lines would pass exactly through the centre of the
compass card. A mark or index is placed at the lower part of the flat plate to
enable the direction to be seen when steering on a meridian course.
The mode of using the apparatus is as follows,-The course having been set out
on the chart the straight edge of the plate is placed along the line on the chart
indicating the course, and the instrument is moved parallel to the line until the
centre hole comes exactly over one of the meridian lines; the compass card is then
turned until its north point comes exactly over the meridian line passing under the
centre hole, and the true course for steering is read off by observing the point of the
compass card opposite the one or other of the lines, according to whether the vessel
is proceeding in one direction or in the reverse direction.
To give the point for steering by the ship's compass, the compass card must be
rotated through the number of degrees denoting the magnetic deviation and then
through the number of degrees denoting the deviation of the ship's compass and the
direction is read off as before.
This apparatus may be employed to make the corrections for the " magnetic
deviation" and for the deviation of the ship's compass when sailing by a book of
sailing directions without the aid of charts
As will be obvious the apparatus may be variously modified without departure
from its distinguishing characteristics.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said George Charles Lilley in the Patent Office on the 28th March
1884.
GEORGE CHARLES LILLEY of Osborne Road, Finsbury Park in the County of
Middlesex IMPROVEMENTS IN APPARATUS FOR LAYING OFF OR ASCERTAINING
SHIPS' COURSES.
In laying off a ship's course it has been usual to place one edge of a parallel rule
on the line joining the point denoting, on the chart, the present position of the ship
and that denoting the place for which the ship is sailing for example, the place
expected to be reached in say twenty-four hours. The parallel rule is then passed
over the chart, in the usual method of operating parallel rules, to the diagram or
compass card, placed in some convenient position on the chart to denoto the points
of the compass, where the direction of the line is read off.
The necessary
corrections for the deviation of the magnetic north from the true north, and of the
ship's compass are then made by calculation
The object of this invention is to provide an instrument by which the direction
of the ship's course can be laid off without transporting the said instrument from
place to place on the chart, and by which the corrections for the deviations may be
made mechanically instead of by calculation.
The instrument consists of a compass card (in which expression is included a disc
or plate marked to degrees or with the points of the compass) mounted so as to
revolve about its centre and partially surrounded by a flat plate in the same plane
(or nearly so) as the compass card and carrying the bearing about which the card
revolves. The axis of the compass card is provided with a thumb piece on its
upper side by which it can be rotated. This axis has a small hole (hereinafter
called the centre hole) drilled through it perpendicularly to the card, passing
through the centre of it, for the purpose of ascertaining the correct position of the
card on the chart.
The flat plate is provided with a straight edge preferably at a greater distance
from the centre of the card than its semi-diameter. Two lines are drawn on the
plate opposite each other parallel to the straight edge and at a distance therefrom
so that a straight line joining these two lines would pass exactly through the
centre of the compass card. A mark or index is placed at the lower part of the flat
plate to enable the direction to be seen when steering on a meridian course.
The mode of using the apparatus is as follows:-
A straight edge is applied on the chart from the point of departure to the place
at which the ship is to arrive, then the straight edge of the instrument is placed
against the other straight edge and moved until the nearest Meridian appears in
the middle of the centre hole then the compass card disc or plate is turned until
the North point thereof is on that Meridian, the true course is then shewn by the
Index line or indicator at the side of the instrument.
The total error can be applied and the Compass course shewn as follows:-If the
total error is Westerly, turn the compass card to the westward or left hand; if
Easterly, to the right; the Compass Course is then shewn by the Index Line or
indicator as before; and if the ship is steering a Northerly or Southerly course the
Parallel can be used instead of the Meridian, by placing the East or West point of
the compass card plate or disc upon it and proceeding as before.
This apparatus may be employed to make the corrections for the " magnetic
deviation" and for the deviation of the ships compass when sailing by a book of
sailing directions without the aid of charts:"
Referring to the accompanying sheet of drawings:-
Fig 1 is a front view of one form of my improved apparatus and Fig 2 a side
view of the came

page_text: Figs 3, 4, 5, 6 and 7 are front views of slightly modified forms of the said
apparatus.
a (Figs 1 and 2) represents the compass card formed of metal or other suitable
material partially surrounded by the flat plate b. which is in the same plane (or
nearly so) as the compass card. c represents a flat plate carrying the bearing by
which the compass card is so mounted that it can be revolved about its centre by
means of the thumb piece d secured to the axis of the compass card in any
convenient manner. In the drawing the plate c is shewn attached to the plate b.
by screws, but the two may be otherwise joined or may be made in one piece. c is
the centre hole drilled perpendicularly through the centre of the compass card for
the purpose of ascertaining the correct position of the card on the chart. f. is the
straight edge formed on the lower portion of the flat plate b. and g. g. are two
lines drawn on the said plate opposite each other parallel to the straight edge f
and at such a distance therefroin that a straight line joining them would pass
exactly through the centre of the compass card. h is the mark or index placed at
the lower part of the flat plate b to enable the direction to be seen when steering
on a meridian course. is an opening or hole formed in the plate e to enable the
mark or index h, and adjacent portion of the compass card to be seen.
In Fig. 3 the plate shown in Figs 1 and 2 is dispensed with and the plate c.
carrying the compass card a on one side of it and the thumb piece d on the other
is formed or provided with two pointers g. g' to serve the same purpose as the
lines g. g shown in Fig 1.
Fig represents an instrument similar to that shewn in Figs 1 and 2 except
that the plate b. almost wholly surrounds the compass card a.
In Figs 5, 6, and 7 are represented other modified means of supporting the
pointers g. g.
It will be obvious that my improved apparatus may be variously modified from
the forms shown in the drawing without departure from the distinguishing
characteristics of my invention.
Having now particularly described and ascertained the nature of my said.
invention and the manner in which it is to be performed I would have it
understood that what I consider to be novel and original and therefore claim as
the invention secured to me under the Letters Patent herein before in part
recited is
-
1. In an apparatus for laying off or ascertaining ships courses the combination
with a moveable compass card (disc or plate) of a straight edge to be applied to
the proposed course and means (such as lines or pointers) for indicating upon tho
compass card (disc or plate) the true course for steering substantially as described.
2. The improved apparatus for laying off or ascertaining ships couises constructed
arranged and operating as hereinabove described with reference respectively to and
illustrated in Figs 1 and 2, in Fig 3, in Fig 4, in Fig 5, in Fig 6, and in Fig 7 of
the drawings.
In witness whereof, I the said George Charles Lilley have hereunto set my hand
and seal this twenty sixth day of March in the year of Our Lord, one thousand
eight hundred and eighty four.
GEORGE CHARLES LILLEY (L.S.)