AN IMPROVEMENT IN SHIPS' LOGS
Year: 1882

page_text: LETTERS PATENT to Frederick Webster, of No 340, City Road, in the County
of Middlesex, for an invention of "AN IMPROVEMENT IN SHIPS' LOGS."-
A communication from abroad by William Webster, Captain of the Steam
Ship Albion, at present on the High Seas.
PROVISIONAL SPECIFICATION left by the said Frederick Webster at the
Office of the Commissioners of Patents on the 2nd March 1882.
FREDERICK WEBSTER of No 340 City Road in the County of Middlesex "AN
IMPROVEMENT IN SHIPS' LOGS" [A communication from abroad by William
Webster, Captain of the Steam Ship Albion, at present on the High Seas.]
Logs such as the harpoon log and others used for ascertaining the speed of a
vessel, in which inclined blades like those of a screw propeller are caused to
revolve registering the number of their revolutions by a counter contained in the
body of the log, are apt sometimes to be falsified by obstructions interfering with
the revolution of the blades. The object of this invention is to give a signal on
board the vessel when such interference occurs. For this purpose the tow line of
the log is attached to the axis of a detector to which is applied an adjustable
amount of resistance by friction or otherwise, and which when it is caused to
revolve, works an index or causes a bell gong or other audible signal to sound.
long as the log is properly working this axis remains stationary but when the
blades of the log are obstructed in such a manner as to cause the body of the log
to revolve in the water, the torsive strain communicated through the tow line
causes the detector axis to revolve thus giving a signal which indicates the failure
of the log.
As

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Frederick Webster in the Great Seal Patent Office on the
31st August 1882.
"
FREDERICK WEBSTER of No 340 City Road in the County of Middlesex
"AN
IMPROVEMENT IN SHIPS' LOGS A communication from abroad by William
Webster of the Steam Ship Albion, at present on the High Seas.
Logs such as the harpoon log and others used for ascertaining the speed of a
vessel, in which inclined blades like those of a screw propeller are caused to
revolve registering the number of their revolutions by a counter contained in the
body of the log, are apt sometimes to be falsified by obstructions interfering with
the revolution of the blades. The object of this invention is to give a signal on
board the vessel when such interference occurs. For this purpose the tow line of
the log is attached to the axis of a detector to which is applied an adjustable
amount of resistance by friction or otherwise, and which when it is caused to
revolve, works an index or causes a bell gong or other audible signal to sound. As
long as the log is properly working this axis remains stationary but when the
blades of the log are obstructed in such a manner as to cause the body of the log
to revolve in the water, the torsive strain communicated through the tow line
causes the detector axis to revolve thus giving a signal which indicates the failure
of the log.
Fig. 1 of the accompanying drawings is a front view and Fig. 2 a vertical
section of one form of apparatus such as is described above. A is a frame fixed to
a wooden or other base and having a central boss through which passes a spindle B
attached to the log line C. On the spindle B is fixed a cam D that when the
spindle B revolves acts on the spring hammer E of a bell or gong F, thus giving an
alarum when the body of the log itself and its line C revolve instead of the vanes
of the log.
Having thus described the nature of this invention and in what manner the
same is to be performed as communicated to me from abroad by my foreign
correspondent I claim
The use of apparatus for detecting and indicating the revolution of a log,
substantially as herein described.
In witness whereof I the said Frederick Webster have hereunto set my hand
and seal this thirtieth day of August in the year of our Lord One
thousand eight hundred and eighty-two.
TRAD WERSTER
WRED WERSTER
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