Improvements in or appertaining to Apparatus for Indicating and Registering the Speed of Maritime Vessels.
Year: 1893

page_text: Date of Application, 18th Apr., 1893-Accepted, 22nd July, 1893
COMPLETE SPECIFICATION.
Improvements in or appertaining to Apparatus for Indicating and
Registering the Speed of Maritime Vessels.
A communication by CHARLES FREMONT HOLT, Pilot, and WILLIAM STORK
STARR, Apothecary, both of New London, in the County of New London and
State of Connecticut, United States of America.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for
Foreign Patent Solicitors, 6 Lord Street, Liverpool and 6 Bank Street, Man-
chester, both in the County of Lancaster and 323 High Holborn, in the County of
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:-
This invention relates to a new system of electrically actuated mechanism for
indicating and registering the speed of vessels, (either steam or sail) and has for its
object the production of more accurate results than have been reached heretofore
with so-called "logs." It also seeks to provide a system of registration that may
be readily transmitted to, and read at, different parts of the vessel, as, for example,
in the pilot house, engine room, cabin &c.
In the ordinary log, towed astern at the end of several hundred feet of cord, the
recording mechanism (controlled by a propeller wheel) is not sensitive enough to
automatically adjust itself to slight changes of speed and in consequence the
registered result is only approximately correct.
This system of speed measurement seeks to overcome this serious defect and to
indicate accurately the distance traversed whatever may be the speed of the
vessel.
The annexed drawings illustrate said invention, Figure 1 being a front elevation
of the indicator proper, used as one element of the complete system, and said
figure also shows an ammeter, switch, battery and pressure gauge, all in a single
electric circuit. Each of said elements is described in detail hereinafter.
Figure 2 shows the case which encloses the indicator mechanism and ammeter,
with its front face removed to expose the interior parts.
Figure 3 is a front view of the pressure gauge of Figure 1 detached and enlarged,
its case being largely cut away, and Figure 4 is a side view of the same.
Figure 5 is a sectional view of said gauge on line x-x of Figure 3.
In Figures 6, 7, 8, 9 and 10 are illustrated a modification of said invention, in
which the pressure gauge is located inboard and actuated by a drag towed astern,
instead of being attached to the vessel below the water line and actuated by a lever
in contact with the water, as in Figures 1 to 5.
Figure 6 illustrates in a general way the manner of using said modification and
Figure 7 shows, about full size, the pressure gauge as attached to a vessel's rail.
Figure 8 is a similar view in vertical section and
Figure 9 is a view of the drag used with said modification.
In Figure 10 are illustrated simple spring mechanisms for controlling (in one
direction) the needle of the pressure gauge.
Said invention consists, in brief, of a drag located beneath the water-line of a
vessel, and connected mechanism, consisting of a simple form of rheostat, which is
traversed by a contact lever (controlled by said drag) in such manner that any
variation in the speed of the vessel acting upon the drag to vary the degree of
resistance, will cause said lever to move in like proportion, upon the rheostat to
vary the strength of the electric current: which current actuates certain mechanisms

page_text: inboard to show both the speed at which the vessel travels and the number of miles
travelled in a given time.
There are here shown two slightly different ways of connecting said drag with
the pointer that forms a part of the rheostat, the first one of which is illustrated by
Figures 1, 3, 4 and 5. Figure 1 shows the manner of attaching said drag to a
vessel, the letter a denoting the rib timbers and a' the keel. Said drag is formed
with a base b of substantially oval form as here shown, and is attached to the keel
by screws or bolts & Projecting outward from said base is a housing 2 that
covers the upper portion of the base and provides a water tight chamber ³. The
lower portion of the housing is cut away and replaced by a wire screen c. Within
the place enclosed by said wire screen is located a lever arm c¹ of paddle form,
that is secured to a shaft 2 journalled in base and the housing 62. Said shaft
extends through a stuffing box 6 in a wall that separates the chamber 63 and the
lower, open portion of the housing and upon the shaft c² within chamber ³ is
mounted a radial pointer d whose free end in its normal position rests between the
confronting ends of the arc-shaped bars e of German silver, which arcs are
supported upon studs el of insulating material. From the outer ends of each of said
arcs e, wires lead together and thence up into the vessel and a similar wire also
leads from the pivot shaft c². An open circuit is maintained when the vessel is at
rest and the pointer d in the position shown in full lines in Figure 3. When, how-
ever, the vessel is under way, in either direction, the lever-paddle c¹ is swung from
its perpendicular position (against the retractile force of a spring upon its shaft)
thus causing the pointer d to come in contact with the inner end of one of said arcs
and closing the otherwise open circuit. When the pointer is brought into contact
with the arc of German silver, the latter, as is well known, will serve as a powerful
resistant and the electric current will be weak, but, as the vessel's speed is increased
and the lever-paddle yields still more to the resistance of the water, the pointer is
correspondingly moved toward the outer end of said arc, thus reducing, pro-
portionately, the length of the resistance bar or arc, between the pointer and the
outer end of said arc. In like proportion as the area of the resistance arc is
lessened by the forward movement of the pointer, the strength of the electric
current is increased. The spring c³ should be of such graduated tension, that a very
slow movement of the vessel will swing the pointer into contact with the arc to
close the circuit, the maximum speed of said vessel being required to force said
pointer to the extreme outer end of said arc.. The described oval form of the
housing and screen c prevents floating or swimming material, as seaweed, from
lodging against said housing and checking the flow of water through the screen.
The resistance gauge thus far described has the advantages of being a fixture upon
the vessel, always ready for use, and of serving to indicate movements of the vessel
either forward or aftward. It is here described as being attached to the keel, but
it could be as readily attached to the bilge or any other portion below the water
line, where unobstructed contact with the water current could be assured.
In Figures 6 to 10, the same general plan prevails as that already described, but,
instead of providing a lever in paddle form which drags in the water, there is
substituted for said paddle a fine line of wire f that is secured to an angle arm d
forming a part of the pointer d, and at the outer end of said line is attached a
drag consisting preferably of several feet of larger cable f¹. It is found in
practice that the fine line cuts through the water freely without regard to its
length, thus making it possible to locate the resistance gauge or rheostat higher or
lower above the water line, according to the size of the vessel, without varying the
pull of the drag f¹, which latter tows under water and always exerts a steady pull
upon the pointer when going at a given speed. In this modification of the said
invention, only one resistance bar e is provided, so that only the forward
movement of the vessel is registered. The housing of the resistance gauge in
said modification is provided with a base that is fastened to the ship's rail,
or other place easy of access, and the electric wires run to any part of the

page_text: vessel where it is desired to locate an indicator and register, in precisely the
same manner as if the resistance gauge was located below the water line as first
described. A spring 3 is also provided to hold the pointer of said modification
normally in contact with a stop-pin g projecting from the rear wall of the
housing. The front face may be of glass, so that the interior parts and their
movements may be observed at all times.
Having described the resistance gauge and the drag that controls it, the register,
indicator and other elements in circuit with said resistance gauge will now be
described.
Referring to Figures 1 and 2, denotes a case of convenient form, in which are
located an ammeter of ordinary construction and electrically actuated recording
mechanism, by means of which latter the distance traversed by the vessel is so
registered that it may be read at a glance. As here shown, said mechanism
registers, by means of the smaller pointer, each quarter mile, and, by the larger
pointer, every ten miles travelled, up to one thousand miles, when the pointers may
be reset at zero.
The register mechanism consists of an electro-motor of any simple form,
having upon its shaft a worm 2 meshing with a gear i that forms the initial or
driving gear of a train calculated to move the pointers to produce the results above
described, but, as said train forms no part of this present invention, it is thought
unnecessary to illustrate and describe it in detail here.
The needle of the ammeter gl has secured to it a pointer g² that projects outside
the case (see Figure 1) and co-acts with a graduated curved scale g³ to indicate
the speed of the vessel. denotes a battery and a switch, both being of any
approved form.
When the invention is in service and the vessel to which it is attached is under
way, the resulting pressure of water upon the drag brings the pointer d into
contact with the arc-shaped piece, e, thus closing the circuit and maintaining a
current of low power, which correspondingly energizes the ammeter and causes its
pointer to move along the graduated scale 93 and also simultaneously sets in slow
revolution the motor and its connected train, thus causing the hands of the
register to crawl slowly along their respective dials. As the speed of the vessel
increases and the pointer d advances along the resistance picce e, the current
throughout the circuit is correspondingly strengthened. The pointer of the
ammeter is then advanced upon its graduated scale to indicate the increased speed
of the vessel, and the registering mechanism also quickens its pace in order to
accurately record the distance travelled. The graduated scale of the ammeter
is preferably marked to indicate the number of miles travelled per hour: that
is to say, when the pointer rests at the mark "5," it indicates that the ship is
travelling at the rate of five miles per hour. Thus it will be seen that, by
means of the described invention, any variation of the speed of the vessel is
immediately indicated by the ammeter and also that the distance traversed by
the ship is accurately registered, whatever may be the rate of speed.
It is sometimes desirable to have the speed and distance noted in different
parts of the ship, as, for example, in the pilot house, chart room and cabin, and,
to provide for such contingency, there is added to the described registering
mechanism a simple device (shown in Figure 2) for making and breaking the
circuit, consisting of a pin m in one of the gears m¹ of the register train and a
spring arm n secured to a binding post n fastened to the register case.
independent electric circuit is then provided including a battery and one or more
registers.
An
At each revolution of the wheel m³, the auxiliary circuit is closed, and the
hands of its register or registers are moved forward one step to correspond to the
movements of the parent register.
It will be obvious that the ammeter could be dispensed with, in which case
only the distance travelled would be indicated, or the register could be removed
from the circuit, in which case only the rate of speed would be indicated.

page_text: Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, as communicated to me by
-my foreign correspondents, I declare that what I claim is :-
1. A distance register for vessels, having, in combination in and with an electric
circuit, a motor with connected train of registering mechanism as set forth, a
battery and resistance gauge, and a submerged drag connected with said resistance
gauge, substantially as specified.
2. In a speed indicator, in combination in and with an electrical circuit
containing distance registering mechanism, a battery and an interposed bar of
resistant material traversed by a contact pointer and a submerged drag as described,
connected with and controlling the transverse movement of said pointer, all being
substantially as and for the purpose specified.
3. In a speed indicator, in combination in and with an electrical circuit
containing distance registering mechanism, a battery and an interposed bar of
resistant material traversed by a contact pointer and a submerged drag connected
with said pointer consisting of a lever of paddle form substantially as and for
the purpose specified.
4. In combination in and with an electrical circuit, registering mechanism, a
battery and a resistance gauge, said gauge being composed of a bar of resistant
material, as German silver, traversed by a pointer as set forth, and enclosed in
a watertight chamber, the shaft of the pointer extending through the housing of
said chamber and bearing upon its outer (exposed) portion a lever of paddle
form, which lever is enclosed by a screen substantially as and for the purpose
.specified.
Dated this 17th day of April 1802
WM. P. THOMPSON & Co.,
Agents for the Applicant.