Improvements in and relating to the Sheathing of Ships and other Vessels, which Im are
Year: 1892

page_text: Date of Application, 15th July, 1892-Accepted, 3rd Sept., 1892
COMPLETE SPECIFICATION.
Improvements in and relating to the Sheathing of Ships and other
Vessels, which Improvements are applicable to the Recovery of
Gold and Silver from the Water in which the Ship or Vessel
Floats.
JOHN BRIDGES LEE M.A. Barrister-at-Law of 3 Brick Court Temple London
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 :-
It is well known that all kinds of ships and boats and other structures of a like
nature which are built for the purpose of being propelled through water whether by
steam power or by electricity or by sails or otherwise are much retarded in their
progress by friction.
The main object of this my invention is to diminish such friction by employing a
smooth surface of metallic mercury spread in a thin film over an amalgamated
metallic surface.
The metallic surface which I prefer to use for holding the mercury film is
amalgamated sheet copper.
The copper sheets may be affixed to the outside of the vessel by any ordinary
means such as have been hitherto used for affixing sheet copper to the bottoms of
ships or by any other means which may be found suitable to the conditions affecting
the particular vessels to be coated.
When iron ships are to be coated care should be taken to secure that the copper
sheeting shall be separated from the iron by a good layer of electrically insulating
material and there should be no short circuit between the copper and the iron as
any direct electrical communication between the outer metallic sheathing and the
iron of the ship's hull would tend to promote corrosion of the iron.
With care
this danger may be avoided and in every case the whole surface of the iron should
be well covered everywhere by a good thick insulating waterproof layer of paint or
varnish or both before the copper plates are adjusted.
In all cases whether the ship's hull be of iron or not the copper sheeting should
be in good metallic connection through insulated copper wires with the zinc end of
a galvanic battery carried within the ship, the opposite pole of which battery must
make good earth outside of and away from the ship. Or the connection may
be with the corresponding pole of a dynamo-electric machine of small voltage or of
a secondary battery. The opposite pole must in every case make good earth away
from the ship. The voltage and ampereage of the electric current passing from the
electricity generating apparatus inside the ship to the metallic sheath should be so
regulated as to secure with certainty that no portion of the exposed surface shall
become corroded by chemical action of salt water. Branch insulated wires from the
battery or dynamo-electric machine should be led to different parts of the metallic
sheath to secure a fairly uniform electrical condition over the whole surface.
Experience will shew in the case of each coated vessel what is exactly the
best voltage and ampèreage to employ and the electrical current must be adjusted
accordingly.
Ordinarily it will be found best to affix the copper sheeting in its unamalgamated
condition and then to amalgamate the whole surface by rubbing with rags wetted
with solution of nitrate of mercury. Afterwards more mercury can be supplied in
the metallic condition either through fine capillary tubes or by any other means
which may be found most convenient and least wasteful in each particular case and
it can be spread over the whole surface by rubbing with rags or cotton waste.
The amalgamation should ordinarily be done only a short time before the vessel is

page_text: to be launched or floated and the sheathing should be kept always in electrical
communication with the zinc end of an active battery or other electricity generating
apparatus in operation.
When vessels sheathed with an amalgamated metallic sheath which is made the
cathode pole of an electrical circuit as above described are floated in water which
contains traces of gold and silver in solution as does the water of the ocean and
of many inland seas a certain quantity of the precious metals will be deposited
upon the surface and will there be held by the mercury in the form of amalgam.
When the vessels are lying up in dock after having been floated for some time
the sheathing can be lightly scraped before being reamalgamated and the scrapings
can be treated by any of the well known chemical processes for recovery of the
precious metals and of the mercury and the value of the metals thus recovered will
be an important set-off as against the value of the mercury lost and the expense of
maintaining the electric circuit.
Also the amount of fuel & time saved from diminished friction will ordinarily
suffice to more than counterbalance any additional expenses consequent upon the
use of my invention and rates of speed will be rendered possible such as cannot now
be obtained with previously existing arrangements.
In describing my invention as above I do not claim as new the use of copper
sheathing per se.
My method consists essentially in the use of an amalgamated metal surface
over the whole ship's bottom whether the metal which carries the mercury be
copper or any other and in making the amalgamated metal sheath an electrical
cathode with the twofold object of keeping the surface always bright and further
of collecting valuable metals from the water in which the vessel floats.
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 :-
:-
1. The use of a film of metallic mercury spread over the surface of an
amalgamated layer of sheet copper or other suitable metal by which the bottom of
the vessel must be covered.
2. The use of an electric current in connection with such metallic sheathing as
described in the body of this Specification.
3. The employment of the metallic sheathing as described for the recovery of
the precious metals gold and silver from the water in which the vessels float.
Dated this 15th day of July 1892.
J. BRIDGES LEE.