IMPROVEMENTS IN SIGNALLING BY SOUND BETWEEN VESSELS AT SEA AND APPARATUS TO BE USED IN CONNECTION THEREWITH
Year: 1881

page_text: PROVISIONAL SPECIFICATION left by John Macfarlane Gray at the Office
of the Commissioners of Patents on the 30th December 1881.
JOHN MACFARLANE GRAY, Engineer of 9 Lonsdale Terrace, Edinburgh, in the
County of Midlothian. "IMPROVEMENTS IN SIGNALLING BY SOUND BETWEEN
VESSELS AT SEA AND APPARATUS TO BE USED IN CONNECTION THEREWITH."
My Invention relates to a method of signalling ships courses by mechanical means
to any desired degree of accuracy by a code of signals so arranged that they can be
understood without having to be committed to memory, and means whereby an
effective collision model is produced by placing portions of an apparatus respectively
in the direction indicated and in the direction in which the sound of the signal has
been received.
The primary object of my Invention is to enable a vessel in a fog to communicate
to vessels in its proximity the direction in which it is moving. At present in
practice such signalling in the case of sailing vessels is limited to three signals viz,
one, two or three blasts of a fog horn intimating how a vessel has the wind. It is
a generally expressed opinion that the present system is inadequate to give neigh-
bouring vessels sufficient information to prevent collisions in fogs.
To remedy this defect various plans have been proposed for signalling by arranged
codes, approximately, the course of a vessel. Hitherto proposed codes have to be
committed to memory, or they have to be read from a table, and the signals consist
of not always the same number of blasts, there is therefore liability of error in
interpretation and sometimes a doubt whether all the signal has been heard. Now
the code system according to my Invention requires, merely, to be understood; it
is not necessary, or even desirable, that the signals should be committed to memory;
and every signal consists of the same number of blasts; so that a part of one signal
can never be read as the whole of another signal.
My code system is as follows:-
The blasts are of two kinds as for examples long and short blasts or clear and
vibratory blasts or continuous and interrupted blasts or blasts of different pitches.
I will now describe the system as with a vibratory or interrupted sound which I
will here call the R sound and a clear sound which I will call the U sound. The
first blast is to be read always either north or else south. As there is an R in north

page_text: and a U in south read R north and U south.
All the following blasts are to be
read either east or else west. On a map cast is always to the right hand, I will
therefore put R for east, and as there is a U in west I will put U for west.
The accompanying diagram Sheet 1 shews how these signals are to be applied to
denote the approximate direction in which a vessel is moving the four concentric rings
in the compass-marked horizon correspond to the four blasts making one signal in a
four blast code, they are to be read outwards. The R arcs are shaded, the U ares
are plain. The circle is first divided into two semi circles, R the north and U the
south indicated by the first blast in the signal: these semicircles are each divided
into two quadrants R and U indicated by the second blast in the signal, that to
the cast is shaded and is indicated by the R blast, that to the west is plain and is
indicated by the U blast. Each of these quadrants is again divided into two octants
R and U indicated by the third blast in the signal, that to the east is shaded and
indicated by the R blast, that to the west is plain and indicated by the U blast.
Each of these octants is further subdivided into two arcs R and U indicated by
the fourth blast of the signal, that to the east is shaded and is indicated by the R
blast, that to the west is plain and is indicated by the U blast. Let the signal
given be R. U. U. R. The first blast R denotes the north semicircle. The second
blast U denotes that the direction lies in the western half of that or the north
west quadrant. The third blast U denotes that the direction lies in the western
half of that quadrant or the west north west octant. The fourth blast R denotes
that the direction lies in the eastern half of that octant or the north-west-by-west
two points. North-west-by-west is the approximate course signalled for all
directions contained within one point on either side of that course. In diagram
Sheet 2 I have given the code for indicating sixteen-courses-by-signals of four
blasts each; as the blasts-have only to be clearly distinguishable from each other
and need not be necessarily the sounds described as R and U blasts, I have
indicated the merely different blasts by a stroke, and a cross. These symbols are
to be read outwards, that is, in the direction signalled, and, as represented, the cross
is substituted for the R in the diagram Sheet 1 illustration, and the stroke for
the U.
In diagram Sheet 3 I have given in the same way as in Sheet 2 the code for
indicating eight courses by signals of three blasts each.
It is evident that a five blast code would on the same plan indicate thirty two
courses. With a few minutes of personal instruction this code system can be made
plain and easy to any one who can "box the compass" and it is evident that the
signals ought not to be committed to memory, the thread of the method merely has
to be caught hold of by the mind and then all is clear.
A convenient method whereby to produce the blasts or sounds in the code order
is by forming the cam barrel or its equivalent of a fog signalling machine with
steps or projections spaced to produce the blasts or sounds in the order required by
the code.
Any suitable arrangement of signalling machine may be employed. Conveniently
the kind known as Barker's may be used. Although I have described the code as
arranged for the first blast to be north or else south which I deem best, yet referring
to diagram Sheet 1, it will be evident that the arrangement may be modified by
turning the divided concentric circles to other opposite points of the compass.
I will now describe a mechanical arrangement by which when an officer places a
handle in the direction indicated by a signal received two small model hulls are
placed parallel to the two vessels respectively and by swinging the arm carrying
these models into the direction in which the signal has been heard, a complete model
of the relative positions of the two vessels is produced similar to the models used
in the courts in trying collision cases. I provide a divided compass plate which
has to be shifted to the course the machine is signalling; above this plate and con-
centric with it there is a smaller plate with a handle to be set in the position of the
course indicated by a received signal. This place carries with it at its centre a
spur pinion and on the fixed spindle of this spur pinion is fixed a small bull model

page_text: I will call A rigidly parallel with the vessel carrying it and pointing in the same
direction; an arm centred on the same spindle between the pinion and the hull
model carries a train of two pinions gearing with the first pinion. The outer
pinion is the same size as the first pinion and it likewise carries a hull model I will
call B fixed with it. These wheels are geared so that when the handle is placed
on the divided compass plate to the course the vessel is making, the one model hull
is then parallel with and in the direction of the vessel, and of course, then, also
parallel with the other model hull. Shifting the arm will not change the direction
of the model hull B. The plate to which the handle is fixed with its central pinion
must be moved round to change the direction of that hull model B and in this
way a simple mechanical device accomplishes the visible enunciation of any
collision problem which the officer on duty may have to consider.
The thinking out of the case is done by the three wheels with greater certainty
it could be accomplished by the officer and thereby an economy of brain power is
effected at a time when an officer requires to have all his wits about him.