An Improved Log.
Year: 1891

page_text: Date of Application, 23rd Mar., 1891
Complete Specification Left, 22nd Dec., 1891-Accepted, 20th Feb., 1892
PROVISIONAL SPECIFICATION.
An Improved Log.
I JAMES WATSON JOHNS, Solicitor, residing at Hermitage Hill House,
Hermitage Hill, Restalrig Road, Leith do hereby declare the nature of this
invention to be as follows:-
The object of this invention is to dispense with mechanical logs from the taffrail
or any other part of the ship, thereby saving the running out of a long line either
attached to a patent log, a mechanical log or the old fashioned log.
The method proposed is to insert into the stem of the ship, below her draught
line a bell opening, the diameter of the bell, being adapted to the size and speed of
the ship this bell opening communicates with a tapered tube, curved at first, in the
line of the keelson, the taper of the tube then is reduced as it rises upwards:
the length of the tube depends upon the situation fore and aft of the chart room, or
any other part of the ship where they wish to read the log.
The tube which terminates in glass, with a scale showing the rise and fall of the
water according as the ship goes fast or slow may be exhibited in the chart room,
and in the engine room, the altitude of the chart room will require a smaller tube
than that of the engine room, assuming that they are at different altitudes.
As the tube may be open or closed at the top, the open tube to be brought
quickly into operation may be filled from the top to show the rise and fall of the
water according to the ship's speed-the closed tube will show the rise and fall, by
the rise and fall of an indicator, floating in the water, and driven upwards or
descending by the varying speed of the ship.
Tarantieth day of March 1891.
J. WATSON JOHNS.
COMPLETE
SPECIFICATION.
An Improved Log.
I, JAMES WATSON JOHNS, Solicitor, residing at Hermitage Hill House,
Hermitage Hill, Restalrig Road, Leith, 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:—
The object of this invention is to dispense with mechanical logs from the taffrail
or any other part of the ship, thereby saving the running out of a long line, either
attached to a patent log, a mechanical log or the old fashioned log.
The method proposed is to insert into the stem of the ship below her draught line
a bell opening, the diameter of the bell, being adapted to the size and speed of
the ship; this bell opening communicates with a tapered tube, curved at first, in the
line of the keelson, the taper of the tube then is reduced as it rises upwards;
the length of the tube depends upon the situation fore and aft of the chart room, or
any other part of the ship where they wish to read the log. The tube which
terminates in glass, with a scale showing the rise and fall of the water, according as
the ship goes fast or slow may be exhibited in the chart room, and in the engine,
room, the altitude of the chart room, will require a smaller tube than that of the
engine room, assuming that they are at different altitudes. As the tube may be open
or closed at the top, the open tube to be brought quickly into operation, may be
filled from the top to show the rise and fall of the water according to the ship's
speed. The closed tube will show the rise and fall, by the rise and fall of an

page_text: indicator, floating in the water, driven against a vacuum by the varying speed of
the ship.
Reference is made to the drawings hereto annexed
Figure. I shows a front view of the log, looking fore and aft.
Figure II shows the log in profile, the arrows indicate the inflow of water due to
the forward motion of the ship.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is
Ascertaining the speed of a ship by the admission of water into a graduated tube
or cone, the entrance to which is submerged and presented in the line of the ship's
motion the speed of the ship being indicated by the rise and fall of the water in
the tube.
Edinbuch 21st Doombou 1901