Improvements in Means for Transmitting Signals or Messages to or from Ships at Sea, and of Giving Warning of the Approach of Vessels to the Land.
Year: 1892

page_text: Date of Application, 22nd July, 1892
Complete Specification Left, 22nd Apr., 1893-Accepted, 1st July, 1893
PROVISIONAL SPECIFICATION.
Improvements in Means for Transmitting Signals or Messages to
or from Ships at Sea, and of Giving Warning of the Approach
of Vessels to the Land.
I, ALFRED RICHARD SENNETT of Brentford, Middlesex, Civil Engineer do
hereby declare the nature of this invention to be as follows :-—
My invention has for its object the transmission of messages between vessels
afloat and the shore or vice versa. The vessels may be either in motion or moored.
My invention consists essentially of means whereby signals are transmitted to a
receiving instrument on board a vessel or from a vessel to the land without
employing a continuous electric conductor or other material connection; also
whereby when such conductor is made use of it may remain at rest or comparative
rest. The signals may be transmitted either electrically or mechanically..
I will first describe my invention as applied to a vessel at anchor-a light ship
for example, in which case I prefer to employ electricity. All attempts known to
me which have hitherto been made to effect communication between ships at anchor
and the shore have proved permanently unsuccessful on account of the great
difficulty experienced in devising means for protecting the cable from abrasion and
rupture by the pitching and rolling of the vessel. For the purpose of enabling
the conductor to remain in comparative rest I cause that portion of the electric
conductor in the vicinity of the anchored ship to be supported by a buoy or buoya
moored at such a depth below low water level as to be unaffected by wave motion,
or in shallow water to remain entirely upon the ocean bed.
To obviate the necessity of connecting the ship with the shore by means of a
cable or otherwise I cause the signals to be transmitted inductively. The cable
passes from a station on the shore along the ocean bed to buoys anchored near the
ship which are arranged to give the conductor any required shape, and this position
of the conductor I term the inducing circuit.
The cable may be continued back to the station on shore or it may stop after
passing once or more round the inducing circuit in which case the end of the
conductor would be bared so that the current would flow home through the medium
of the water.
Any suitable arrangement of parts may be made use of for recording the
passage of the induced currents and the record may be made either aurally,
visually, mechanically, chemically, or thermally. By preference I make use of the
aural method and for the purpose of minimising or eliminating disturbance by
extraneous induction, I prefer to employ an electrical current or currents composed
of rhythmic pulses baving phases of known periodicity.
The electrical current may be converted into an intermittent current of known
frequency by means of a revolving commutator controlled by a chronometric
governor or by means of a vibrator making and breaking by means of mercury
cups or by any other suitable device. The current passes from the interrupting
device along the cable and traverses the inducing circuit completing the circuit
either by return cable or by the water. The starting and stopping of currents in
the inducing circuit sets up currents in the inductor portion of the receiving
apparatus. The current thus induced circulates in an electro-magnet and causes
the vibrations of the diaphragm which I preferably place under tension such that
the vibrational period of its fundamental note shall be in unison with that of the
inducing current. Signals may be obtained from such diaphragm directly, or the
latter may be made to interrupt a microphonic circuit which passing through an

page_text: electro-magnet actuates a diaphragm which is also preferably set to isochronous
unison with the phase of the inducing current.
The acoustic wave of the diaphragm is transmitted to the air contained in a
resonance chamber whence the sound is conveyed to the car by a flexible tube or
tubes. I prefer to duplicate the receiving apparatus above described so as to have
a separate instrument for each car.
When it is desired to obtain a permanent record the resulting currents may be
made to pass through a travelling strip of chemically prepared paper in the way
common in electro-chemical recording telegraphs, or, for visually recording, the
current, may cause the deflection of a magnetic needle or coil. I prefer the aural
method when the distance through which the inductive influence has to be made
is considerable and also when it is desired to transmit speech. I will now describe
my invention as applied to signalling to or from ships in motion. In this case it
is inconvenient for the vessel to pass near to the inducing circuit and I prefer to
dispense with the latter and to transmit mechanical vibrations through the water,
but the receiving instrument remains substantially the same.
The vibrations may
be transmitted to the water either pneumatically, hydraulically, mechanically, or
directly by steam. For transmitting mechanical vibration to the water an ordinary
siren submerged and driven independently, so that the vibrational period trans-
mitted to the water shall be constant and in unison with that of the receiving
instrument, may be employed. Or I may make use of an ordinary bell whose
fundamental note is in unison with that of the receiving apparatus. The siren or
bell may be worked so as to transmit signals by the ordinary dot and dash code.
The vibrations imparted to the water are transmitted to the diaphragm of the
receiving apparatus. The acoustic waves produced by this diaphragm may be
heard directly or they may be caused to induce an electric current or to interrupt
that of a microphonic circuit as before described. When it is desired to utilise
my invention for giving warning in vessels of their approach to the land I make
an addition to the recording instrument whereby the direction from which the
signal is being received may be ascertained and recorded. This is of especial
importance during foggy weather. One great difficulty in fog signalling as
hitherto carried out by transmitting sound through the atmosphere has been found
to be due to aerial refraction and reflection from what have been termed acoustic
clouds, but which are in reality strata of the atmosphere at different temperatures,
and of different degrees of aqueous saturation. The existence of such strata in
the atmosphere has the effect of impeding the transmitting of sound vibrations to
an extraordinary extent. From the fact that atmospheric conditions are subject
to rapid change it follows that the atmospheric, penetrability of sound is also
subject to sudden variations which give rise to dangerous effects, thus, for example,
during one hour of the day the signal may be heard for 15 miles, whilst during the
next hour, without any visible change in the atmospheric conditions, a signal of
exactly equal power may only be heard 5 miles. The comparative homogeneity of
the sea and its freedom from rapid alteration in acoustic penetrability, coupled
with the fact that the velocity of an acoustic wave is some four to five times
greater in sea water than in air, renders the former a far better medium for the
transmission of signals than the latter. I therefore prefer to make use of it, and
when employing my invention for warning or signalling in foggy weather, the
siren, or bell, (or other means of imparting mechanical vibration to the water) may
be constantly signalling the name of the station or the code signal by means of
which the station would be recognised. The diaphragm would in this case be
supported preferably vertically in some convenient position upon the vessel, and
capable of articulation about a vertical axis, the direction of which can be recorded
by a suitable dial or other mechanism placed on or within the vessel. The
maximum effect of the transmitted vibrations is obtained when the axis of direction
of the said vibrations is normal to the plane of the diaphragm and thus the
direction of the land station is ascertained by turning the latter upon its axis
until the recorded signals attain their maximum strength.

page_text: The direction of the signalling station in relation to the course of the vessel
may be read off by the dial or other suitable mechanism.
Dated this 22nd day of July 1892.
W. H. MUNNS,
Agent for Applicant.
COMPLETE SPECIFICATION.
Improvements in Means for Transmitting Signals or Messages to
or from Ships at Sea, and of Giving Warning of the Approach
of Vessels to the Land.
I ALFRED RICHARD SENNETT, of Brentford, Middlesex, Civil Engineer, 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 :-
My invention has for its object the transmission of messages between vessels
afloat and the shore. The vessels may be either in motion or moored.
My invention consists essentially of means whereby signals are transmitted to a
receiver on board a vessel (and vice versa) without the necessity of employing a
continuous electric conductor, or other material connection, also, when such
conductor is made use of, it may remain at rest, or comparative rest.
The signals
may be transmitted electrically or mechanically.
I will first describe my invention as applied to a vessel at anchor-a light ship
for example-in which case I prefer to employ electricity.
All attempts known to me, which have hitherto been made to effect com-
munication between ships at anchor and the shore, have proved permanently
unsuccessful on account of the great, difficulty experienced in devising means for
protecting the cable from abrasion and rupture by the pitching and rolling of the
vessel. For the purpose of enabling the conductor to remain at comparative rest,
I cause that portion of the electric conductor in the vicinity of the anchored, ship
to be supported by buoys moored at such a depth below low water level as to be
unaffected by wave motion, or in shallow water to remain entirely upon the ocean
bed. For the purpose of obviating the necessity of connecting the ship with the
shore by means of a cable or otherwise I cause the signals to be transmitted
inductively.
In order to render my said invention clear I refer to the accompanying drawings.
Fig. 1 shows my method of bringing the conducting cable within convenient
distance of the recording, or transmitting, instrument on board, in order that the
latter may be actuated by means of induced currents, the cable being thereby
relieved of abrasion and strain by wave motion.
A represents the land signalling station and Z the floating station. The cable A'
passes from station A along the ocean bed to the buoys B, B, which are anchored
and are preferably connected together by the chains b, The buoys are arranged
to give the conductor any required shape in plan. This portion of the conductor
I designate the inducing circuit.
At Fig. 2 the inducing circuit is shown in the form of a hexagon. Instead
of the buoys being separated by a considerable space they may be connected
together as shown at Fig. 3, or one buoy of the shape desired for the conductor
may be used as at Fig. 4. The cable may either continue back to A, as shown by
dotted lines, or it may stop after passing once or more round the inducing circuit,
as shown at C', in which case the end of the conductor would be bared so that
the current would flow home through the medium of the water. I prefer to
employ the latter method, and also to cause the conductor to pass at least a
hundred times round the inducing circuit. The inducing circuit may be of any
arrangement or shape and may be carried by a single buoy as at Fig. 5, where
the coil is shown in section at a', a'. In shallow water the inducing circuit a

page_text: may lie upon the bed as at Fig. 6. Paramagnetic material may or may not be
employed.
Any suitable arrangement of parts may be made use of for recording the
passage of the induced currents, and the record may be made aurally, visually,
mechanically, chemically, or thermally. In preference I make use of the aural
method, and for the purpose of minimising or eliminating disturbance by extraneous
induction, I prefer to employ an electric current or currents composed of rhythmic
pulses having phases of known periodicity. Fig. 7 shows a method of transmitting
and receiving signals according to my said invention. An electrical current
proceeding from 1 passes to the device 2 for converting it into an intermittent
current of known frequency, which, may be a revolving commutator controlled by
a chronometric governor, or a vibrator making and breaking by means of a
mercury cup 3, or other suitable device. The current passes from the interrupting
device along the cable 4, and traverses the inducing circuit 5 completing the
circuit to either by the cable or by the water. The starting and stopping of
currents in the inducing circuit 5 sets up currents in the inductor portion 6 of the
receiving apparatus. The current thus induced circulates in the electro-magnet 7,
and causes the vibration of the diaphragm 8, which I prefer to place under tension
such that the vibrational period of its fundamental note shall be in unison with
that of the inducing current. The signals may be obtained from such diaphragm
directly, or the latter may be made to interrupt a microphonic circuit 9, with
battery 14, which circuit passing through an electro-magnet 10 actuates a
diaphragm 11, which is also set preferably to isochronous unison with the phase of
the inducing current. The acoustic wave of the diaphragm is transmitted to the
air contained in the resonance chamber 12, whence the sound is conveyed to the
ear by the flexible tube 13. I prefer to duplicate the receiving apparatus above
described, employing a separate instrument for each car.
When it is desired to obtain a permanent record the resulting currents may be
made to pass through a travelling strip of chemically prepared paper in the way
common in electro-chemical recording telegraphs, or for visually recording, the
current may cause the deflection of a magnetic needle. I prefer the aural method
where the distance through which the inductive influence has to be made is
considerable, and also where it is desired to transmit speech.
I will now describe my invention as applied to signalling to or from ships in
motion. In this case it is inconvenient that the vessel be made to pass in proximity
to the inducing circuit, and I prefer to transmit mechanical vibrations through the
water, but the receiving instrument remains substantially the same as above
described. The vibrations may be transmitted to the water pneumatically,
hydraulically, mechanically, or directly by steam. Fig. 8 will serve to show
substantially the method I employ in carrying out my invention, and in which I
take the simple case of an ordinary siren submerged as shown at A, with this
modification, that the siren is driven independently, so that the vibrational period
transmitted to the water shall be constant and in unison with that of the receiving
instrument. The siren may be actuated either by steam, air, or water, and may
conveniently have independent motion imparted to it by electricity, using an
electro-motor M. or a bell, the fundamental note of which is in unison with that
of the receiving apparatus may be made use of. The siren or bell may be worked
so as to transmit signals by the ordinary dot and dash code. The vibrations
imparted to the water by the siren S, which may be driven at constant speed by an
electro-motor M, are transmitted to the diaphragm 11 of the receiving apparatus.
This receiving diaphragm may be fixed to a tube 16 passing upwards from the
shell of the ship to a point above the water line. The acoustic waves produced
by this diaphragm, the vibrational period of which should be in unison with that
of the transmitted vibrations, may be heard directly or they may be caused to
induce an electric current or to interrupt that of the microphonic circuit as herein
before described.
When it is desired to utilise my said invention for giving warning in vessels of

page_text: their approach to the land I make an addition to the recording instrument whereby
the direction from which the signal is being received may be ascertained and
recorded. This is of especial importance during foggy weather. The comparative
homogeneity of the sea and its freedom from rapid alterations in conditions coupled
with the fact that the velocity of the acoustic waves is some four to five times
greater in sea water than in air renders the former a far better medium for the
transmission of signals than the latter. I therefore prefer to make use of the
water in preference to the atmosphere. When employing my said invention for
warning signalling in foggy weather, the siren, or bell, or other means of imparting
mechanical vibration to the water may be constantly signalling the name of the
station or the code signal by means of which the station would be recognised.
The diaphragm would in this case be supported preferably vertically in some con-
venient position upon the vessel and capable of articulation about a vertical axis,
the direction of which could be recorded by a suitable dial or other mechanism
placed on or within the vessel. The maximum effect of the transmitted vibration
is obtained when the axis of direction of the said vibrations is normal to the plane
of the diaphragm, and thus the direction of the land station is ascertained by
turning the diaphragm until the recorded signals attain their maximum strength.
The direction of the signalling station in relation to that of the course of the
vessel may be read off by the dial or other suitable mechanism before mentioned.
Fig. 8 shows a method of carrying this into effect. The vibrations are received
upon the diaphragm 16ª fixed to the end of the projecting tube 17ª which is
capable of movement round its axis, the amount of which movement may be
recorded on a suitable quadrant, dial, or other mechanism. The recording instru-
ment may be the same as herein before described.
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:
1. In signalling to or from ships at sea the méthod of obviating the necessity of
connecting a ship by a cable to the land by transmitting signals inductively by
means of a submerged inducing current.
2. In signalling to or from ships at sea the employment of intermittent electric
currents of definite periodicity in combination with receiving and recording
apparatus in isochronous unison with such periodicity.
3. In signalling to or from ships at sea the method of employing mechanical
vibrations of the water for conveying messages in combination with receiving and
recording apparatus.
4. In signalling to or from ships at sea the employment of mechanical vibrations
of definite periodicity in combination with receiving and recording apparatus in
isochronous unison with such periodicity.
5. In signalling to or from ships at sea the method of localising the direction of
the signal given by the employment of a receiving apparatus movable upon a
vertical axis substantially as described and shown in Fig. 8.
11000
W. H. MUNNS,
Agent for Applicant,