An Improved Method of and Means for Indicating the Mean Draft of Ships.
Year: 1894

page_text: COMPLETE SPECIFICATION.
An Improved Method of and Means for Indicating the Mean Draft
of Ships.
We, ALFRED ERNEST WILSON, of "Kilvington," Sydenham, Surrey, Master
Mariner, and THOMAS THORPE, of Grosvenor Street, West Hartlepool, Marine
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 consists in a method of and means for indicating within a ship
the draft thereof. Under this invention a guide is provided within the ship itself
against either overloading or underloading.
According to one method comprised in this invention, a water gauge is employed
and is placed directly in the longitudinal axis of the ship and opposite the load line
discs or marks.
The water-supply tube of the gauge is connected thereto at the lower end thereof
It is fitted
and is carried out through the ship's side below the level of the water.
with a stop-cock.
The tube is carried in supports connected to a plate designed to be fixed to a
bulkhead or other convenient support. To the plate aforesaid is attached a
graduated index plate after adjustment, as hereinafter described. The plate which
carries the gauge supports is first fixed by bolts or screws to the bulkhead or other
support aforesaid, the position being such that the top of the gauge tube is
sufficiently above the level of the ships' load line as to adapt the instrument for use
in fresh as well as salt water. The stop-cock of the water pipe is then opened and
the mean draft ascertained by the usual method of taking the mean of the readings
of the figures shown at the bow and stern. The index plate is then applied to the
gauge tube and a suitable graduation on the index plate is made to coincide with
the water level in the gauge tube. The index plate is then fixed, and the usual
load lines marked on the ships' side may be repeated on the index plate. A con-
venient time for fixing the gauge and setting the index plate is when the ship
is nearly fully loaded. The level of the water in the tube varies with the load,
and the gauge serves as a guide within the ship in loading, and, consequently,
as a guard against overloading or underloading.
In cases where the arrangements are such that the gauge cannot be placed in
the position above described, two such gauges are employed, each placed in the
longitudinal axis of the ship and equidistant fore and aft of the load line discs
which indicate the maximum mean draft. The mean of the readings of the two
gauges gives the mean draft of the ship.
In the accompanying drawing
Fig. 1 represents a front view of a gauge arranged and fitted in accordance with
this invention for indicating within a ship the mean draft thereof. The glass
gauge tube a is shown in section.
Fig. 2 is a side elevation. The tube a is carried at bottom in a stuffing box b
over the gland cof which is a nut d. The stuffing box is fixed to the holder plate e
At bottom the latter
by pins el passed through lugs fextending from the box b.
is connected by a union to the water-supply pipe g which is open to the water
in which the ship floats. The pipe g is fitted at any convenient point with a
It is also furnished
stop-cock for controlling the communication with the water.
with a drain cock for emptying the tube a. At its upper end the tube a fits
into a ring open at top and bottom and carried on a stud / fixed in the plate e.
The ring h, which is capable of turning on the stud / for convenience in inserting
h

page_text: or withdrawing the tube, is fitted with an open-topped band m across which extends
a bar in which is screwed a spindle n carrying a vertically adjustable hood o open
below to the atmosphere. Partially embracing the tube a is a winged index
plate i graduated to feet and inches or other standard or accepted divisions.
The plate e with the gauge attached is first fixed to a bulkhead k, or other
convenient support. The position of the gauge when fixed is directly in the longi-
tudinal axis of the ship, that is to say, on her centre line and midway between the
load line discs, that is to say, opposite them. The top of the tube is above the
maximum load line level. When the ship is loaded to such an extent that the water
reaches a suitable height in the gauge tube a the ship's mean draft is ascertained
by taking the mean of the readings of the external figures shown at the bow and
stern. The index plate i is then applied to the tube and one of its graduations
made to coincide with the water level. This graduation is then numbered with the
figure expressing the ship's mean draft at that stage. A sufficient length of the
index plate i remains above the water level to serve as an indicator in completing
the loading.
The plate is then fixed to the plate e and major divisions are numbered in
regular order above and below from the graduation first numbered, as aforesaid.
In addition to the graduations the plate i may bear the various load lines usually
adopted.
In cases where the arrangements are such that the gauge cannot be placed in the
position above described, two such gauges are employed, each placed in the
longitudinal axis of the ship and equidistant fore and aft of the load line discs
which indicate the maximum mean draft. The mean of the readings of the two
gauges gives the mean draft of the ship.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is
The hereinbefore described method of and means for indicating within a ship the
mean draft of such ship; viz., by a water gauge (or by two such gauges) having a
glass gauge tube such as a carried upon a holder plate such as e fixed to a bulkhead
or other convenient support and fitted with a graduated index plate such as i
applied to the gauge tube and adjusted and fixed to indicate the mean draft of the
ship in loading as above set forth.
Dated this 20th day of March 1894.
NICHOLAS WATTS,
Bristol, Chartered Patent Agent.