Improvements in Apparatus for Indicating the Course of Ships.
Year: 1889

page_text: COMPLETE SPECIFICATION.
Improvements in Apparatus for Indicating the Course of Ships.
I, JACOB HOLM of Copenhagen in the Kingdom of Denmark, Sea Captain, do
hereby declare the nature of this invention and in what manner the same is to be
performed to be particularly described and ascertained in and by the following
statement:
The present lantern system suffers from the defect that it only shows the course of
a ship within 9-10 points of the card, and it cannot be doubted that it would be of
great advantage to sailors if this defect could be even partially remedied. It would be
of great importance especially to steamers, partly because of the ever-increasing speed
with which these ships are driven, and partly because they are superseding sailing ships
more and more, and indeed so quickly that it may be safely assumed that the steamer
or at any rate a ship that does not use wind as the propelling force, will be the ship of
the future.
The sailor has however grown so accustomed to the present lantern system which
has now been in use for a number of years that it would be very unwise to do away
with it or to make any alteration in it.
To remedy the above mentioned defect I have constructed a special lantern, which
is to be used at the same time as the lanterns which are necessary according to the
present system and is placed a few feet underneath the masthead light at present
used.
In the accompanying drawing an example of such a lantern is shown in section;
it is constructed as follows:-The lantern has exactly the same form as the mast-head
lantern at present used, except that it has circular or plano sides through which the
rays fof the light pass, whilst it is closed behind or on the other side by an opaque
screen a.
The inside of the lantern is divided into several segments by walls s which are placed
radially and approach nearly to the flame, and each of these segments is provided with
a lantern glass of different colors, viz. either white 4, red r, or green g, so that the light
gives a different color for each segment. Some of these may be provided with an
opaque screen m instead of with a lantern glass.
The above mentioned separating walls are made so that they may be taken out, in
order that the inner side of the glasses may be cleaned.
The lantern is as has already been said intended to be placed a few feet under the
mast-head light of steamers now used, so that its circular portion is in front and the
screen a behind.
When one is directly in front of the ship one will see no light because of the
screen 2.
The screen m also obscures so great a segment that during the turning of the ship
the lantern will not show a colored (i.e. either a red or green) light until some time
after one of the side lights of the ship has gone out of sight and when the turning is
continued, so that the ship comes more or less broadside on the lantern will show a
white light.
One obtains by this method much more correct information of the ship's course than
that which the side lights could alone give, whilst at the same time a great alteration
from the course is shown by the changing of the color of the light.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed 1 declare that what I
claim is
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A course indicator for ships intended to be placed a little under the mast head light
in general use consisting of a specially-arranged lantern having the interior divided

page_text: into segments by separating walls s placed radially to and approaching nearly to the
flame and arranged to take out, which segments are provided according to circum-
stances either with lamp glasses h, r, g, of any given color-for example, white, red or
green or with a dark wall m, in combination with the mast-head light in general use,
in order to more exactly show the position of the ship with respect to another ship in
sight, and by which means a greater or lesser alteration of the course is signalled by
the changing of the color of the light.
Dated this 30th day of September 1889.
CARPMAEL & Co.,
Agents.