Improved Signalling Apparatus for Preventing Collisions at Sea.
Year: 1889

page_text: Date of Application, 23rd Nov., 1889
Complete Specification Left, 22nd Aug., 1890-Accepted, 27th Sept., 1890
PROVISIONAL SPECIFICATION.
Improved Signalling Apparatus for Preventing Collisions at Sea.
I JOHN ALEXANDER CAMERON ROTAVEN of 40 Lower Sackville Street, Dublin,
Engineer, do hereby declare the nature of this invention to be as follows:-
The object of my invention is to prevent collisions at sea, more particularly at
night, by providing means for showing approaching vessels, not only the course
that each is steering, but every alteration of such course immediately the helm is
moved.
I use the present system of side and mast head lights so far as it goes; but my
invention enables them to be utilized in such a manner as to give the above
mentioned information to any approaching vessel. At present, vessels in motion
carry a red light on the port side, and a green light on the starboard side. The
rule of the road at sea is to pass on the port side i.e. each vessel to shew her red
light; when there is plenty of sea room, and vessels are far enough away from each
other, it does not of course matter what side they pass on, but in foggy weather
or confined situations, the rule of the road is most necessary, and yet frequently
circumstances occur which makes it contributory to a collision, in the absence of any
indication as to the particular move the opposite vessel means to take. Seamen have
always felt the want of such indication as my invention purposes to supply.
The means provided by my invention to avoid confusion in such cases and to inform
each commander of the movements of the other, is as follows:-
To the mast head light, which is always white, I attach a red and a green shutter,
in such a manner that when moved into position they will change the white light into
a red or a green light as required. These shutters are moved automatically in
sympathy with the movements of the helm, by means of a cam actuated by the
steering wheel or by any other known mechanical or electrical appliance, and moved
in such a manner as will cause a red light to be shewn whenever the helin moves
to port, a green light when it moves to starboard, leaving the light white so long
as the helm is amidships.
With this appliance a vessel, when steering a straight course, would shew (as at
present) a red light on her port side, a green light on her starboard side, and a white
light at her mast head; when steering with her helm to port, she would shew the
usual red and green lights on her sides, but a red light at her mast head. When
steering with her helm to starboard, she would shew the usual red and green lights on
her sides, but a green light at her mast bead.
These well known colours would at once suggest the steering action to a seaman's
mind;
and the apparatus being perfectly automatic, it will be always in use, and
not merely for application when occasion arises, at which time excitement or confusion
frequently causes the total forgetfulness of apparatus provided for exceptional use.
The use of my invention may be shewn as follows:-
Assuming that two vessels A and B are steering straight courses and approaching
nearly stem on, but slightly to starboard; with my above described invention, they
each shew to the other a green side light and white mast head light, consequently
both know, not only that they are passing to starboard, but steering with helm
amidships; with perfect confidence they can keep on their courses if there is room to
pass or can starboard slightly (shewing the green mast head light by so doing) and so
increase their distance from each other; even at the worst, supposing A sees B's mast
head light change to red, he knows that he is porting his helm, as soon as the
movement is begun, not after it is finished as is ordinarily the case, and can take
immediate steps to ensure his own safety, either by porting his own helm or backing
his engines, or doing whatever his experience or skill will suggest.

page_text: To enable this invention to be applied to sailing vessels, which do not carry a
mast head light, I propose that a mast head light be carried by them, and that a
distinctive light be carried in addition, either by sailing vessels or steamers, to
distinguish the one from the other.
In the event of the mast head light being an electric light, the alternative plan of
having three lights, red white and greeu, one of which would become incandescent as
required, might become most suitable: This alternative plan of 3 separate lights,
might if found suitable under peculiar circumstances be applied to vessels using
ordinary lights, by having 2 lights covered as required by opaque shutters.
The foregoing invention applies more particularly to vessels approaching each other
at night, but it might be made equally available during daylight by constructing the
frames or other parts of the moveable shutters so as to be distinctly visible and
of colors corresponding to the lights, or by substituting for them other visible marks
or signal boards, which would in the same manner indicate the movements of
the helm.
It will be seen that the essential advantage of this invention lies in the fact that the
indications given by the signal lights shew the movements intended as soon as the
order is given, and before the movement has actually begun, as in most cases some
little time elapses before a ship obeys her helm, and thus the earliest intimation of her
intended movement is signalled, while under the old system the vessel must turn to a
certain extent before the light on her side which indicates it shews the motion.
Dated this 23rd day of November 1889
COMPLETE SPECIFICATION.
Improved Signalling Apparatus for Preventing Collisions at Sea..
I, JOHN ALEXANDER CAMERON RUTHVEN, of 40 Lower Sackville Street, Dublin,
Ireland, 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 relates to automatic means of shewing to any vessel at sea the course
that another vessel is steering, and every alteration of the course, so that when vessels
approach each other, the steersman in one knows what the steersman in another is
doing, and thus both can steer in such a manner as to avoid collision. The signals
which I adopt for this purpose correspond with those which are now in general use,
that is to say, a red and a green light. As a red light is carried on the port side of a
vessel and a green light on the starboard side, so I employ a red light to indicate that
the helm is moved to port and a green light to indicate that it is moved to starboard.
I place these lights, which may be separate lamps or may be the light of one lamp
seen through one or other of two coloured screens, high up on the mast, either instead
of or in addition to the ordinary white mast head light, and I connect the lamp or the
screens to the steering gear of the vessel so that, when the helm is amidships, the
white light alone visible on the mast, when the helm is being moved or is held to
port, the red light is visible, and when the helm is being moved or is held to starboard,
the green light is visible. The mode of connecting these signal lights to the steering
gear may be varied, but in order that my invention may be carried out in practice
shall describe by way of example apparatus for that purpose, referring to the accom-
panying drawings of which
Figs. 1 and 2 are respectively a front and a side view of upper and lower parts of a
mast provided with signalling apparatus to be operated according to my invention.
Fig. 3 is a plan.
On the upper part of the mast A which is provided with the usual mast head
light MI fix a casing B in which there is a lamp F fronted by a vertically sliding
screen C made in three parts, one red glass, one green glass and the part between

page_text: opaque. Instead of employing a separate mast head light G, the lamp F may serve
for mast head light, and in this case the middle part of the screen C would be of plain
glass or quite open. The screen C is connected by cords D to a pulley E mounted
on the mast near the deck. On the axis of this pulley is fixed a pinion E¹ made with
one tooth and on each side of a concave part formed in its periphery.
The tooth of the pinion E engages with a pair of teeth on a wheel G having on its
axis a grooved pulley H from which cords K and L lead to the port and starboard
steering chains respectively.
When the helm is moved to the one side or the other one of the cords K or L is
loosened and the other is tightened, causing the pulley H and wheel G to make a
partial revolution.
The first part of the movement of G from its middle position causes the pinion E¹
to move partly round until the teeth escape, and the farther movement of G gives no
more motion to E' which is held stationary in the position to which it has been moved
by the engagement of the periphery of G in the concave part of the periphery of F.
By the movement thus imparted to E' and the pulley E one of the cords D is loosened
and the other is tightened, raising or lowering the screen c so as to bring the red or
the green glass in front of the lamp F, and thus to shew which way the helm has been
moved. The signal thus given remains until the helm is again moved to middle
position, bringing back the pinion E¹ to the position shewn in Fig. 1.
Obviously, instead of employing a single lamp with coloured glasses moveable in
front of it, separate coloured lamps might be used with opaque screens moved in
front of them or themselves arranged to be moved behind opaque screens.
When electricity is available, two electrical lamps may be employed, the one red
which is switched into circuit by the movement of the helm to port, the other
green which is switched into circuit by the movement of the helm to starboard.
When a single electrical lamp is employed for signalling with coloured screens moved
as described by the pinion E¹ the conductors to the lamp in order to economise
expenditure of electricity should have in their course a switch worked by the pinion
so as to close the circuit only when the pinion is moved from its middle position.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
The herein described method of automatically signalling a ship's course by connecting
to the steering gear pulls or their equivalents whereby a red or green light is shewn
on the mast according as the helm is moved to port or to starboard.
Dated this 22nd day of Angust 1890
ABEL & IMRAY,
Agents for the Applicant.