IMPROVEMENTS IN MARINE PRO- PELLERS FOR SHIPS AND BOATS, AND FOR THE SHEATHING OF IRON SHIPS WITH
Year: 1862

page_text: LETTERS PATENT to Robert Griffiths, of 69, Mornington Road, Regent's
Park, Engineer, for the Invention of "IMPROVEMENTS IN MARINE PRO-
PELLERS FOR SHIPS AND BOATS, AND FOR THE SHEATHING OF IRON SHIPS WITH
"
Sealed the 22nd August 1862, and dated the 29th May 1862.
PROVISIONAL SPECIFICATION left by the said Robert Griffiths at the
Office of the Commissioners of Patents, with his Petition, on the
29th May 1862.
I, ROBERT GRIFFITHS, of 69, Mornington Road, Regent's Park, Engineer,
do hereby declare the nature of the Invention for "IMPROVEMENTS IN MARINE
PROPELLERS FOR SHIPS AND BOATS, AND FOR THE SHEATHING OF IRON SHIPS WITH
METAL SHEATHING TO KEEP THEM FROM FOULING," to be as follows:-
My improvements consist, first, in constructing screw propellers for steam
ships and boats with the blades and. centre boss of similar form and con-
struction (or the blades may be cast on the boss) to those described in the
Specification of the Patent granted to me on the Twentieth of February, One
thousand eight hundred and fifty-eight, No. 319, but having four blades (or
two sets of blades), which are to be fixed either to the same boss or to
separate bosses on to the screw shaft, and so fixed that one set (or pair of
blades) is placed before the other set, the first set or pair of blades next the
shaft to be of larger diameter than the after set, so as to get a greater hold
on the water for propelling the ship.

page_text: The second part of my Invention relates to side wheel propellers, which I
propose to construct of discs of suitable diameter, having the centre parts
constructed with arms and centres similar to those generally used for paddle
wheels, but having the outside rimis of such discs corrugated or in a zig-zag
form instead of being flat, in order to offer sufficient resistance when driven
through the water to propel the vessel. Either one or a series of these discs
or wheels can be used on each side of the vessel as may be required to propel
the ship, or the outside rims may be made flat, and the inside rims only be
made corrugated or in zig-zag form.
...
The third part of my Invention relates to the sheathing of iron ships with
copper or other suitable sheets of metal (such sheets being perforated with
holes stamped therein) to keep them from fouling, and this I propose to do
in the following manner:-The bottom of the ship should be first well cleaned
and painted over with one or more coats of red lead, paint, or any other
'suitable material to preserve the iron. I then cover the part required to be
sheathed with metal sheathing with some prepared adhesive material, such as
a mixture of tar, pitch, or other suitable substance, and upon that I lay a
coating of felt, gutta percha, or other suitable materials, and on that I again
place another coating of adhesive materials, upon which I place the perforated
metal sheathing, which is made warm on being applied to the ship's bottom,
and is pressed on to the adhesive material until it comes through the per-
forated holes made in the metal sheathing; or the holes can be filled with
short metal nails made rough, so as to set and fix themselves in the adhesive
materials. I then propose to solder the edges of the sheathing sheets together,
and to line the side of the ship at or above the water line with a cleating of
wood well secured to the vessel, so as to protect the covering and adhesive
materials, and to which I secure the edges of the sheathing metal with
sheathing nails.
I also propose, if necessary, to place narrow pieces of
elastic substances (or strips of wood) well secured to the ship along the
ship's side at suitable distances; to which I fix the sheathing with nails, in the
same manner as above proposed, to the top cleating. .

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-ninth day of May, in the year of our
Lord One thousand eight hundred and sixty-two, in the twenty-fifth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Robert Griffiths, Her special licence that I, the said Robert
Griffiths, my executors, administrators, and assigns, or such others as I
the said Robert Griffiths, my executors, administrators, and assigns, should at
any time agree with, and no others, from time to time and at all times
thereafter during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN MARINE PROPELLERS FOR SHIPS AND BOATS, AND FOR THE
SHEATHING OF IRON SHIPS WITH METAL SHEATHING TO KEEP THEM FROM FOULING,"
upon the condition (amongst others) that I, the said Robert Griffiths, my
executors or administrators, by an instrument in writing under my, or their,
or one of their hands and seals, should particularly describe and ascertain the
nature of the said Invention, and in what manner the same was to be per
formed, and cause the same to be filed in the Great Seal Patent Office
within six calendar months next and immediately after the date of the said
Letters Patent.
NOW KNOW YE, that I, the said Robert Griffiths, do hereby declare
the nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement thereof, that is to say :-
My improvements consist, first, in constructing screw propellers for steam
ships and boats with blades and centre boss of similar form and construction
(or the blades may be cast on the boss) to those described in the Specification
of a Patent granted to me the 20th February 1858, No. 319, but having four
blades (or two sets of blades) which are to be fixed either to the same boss
or to separate bosses on to the screw shaft, and so fixed that one set (or pair
of blades) is placed before the other set, the first set or pair of blades next
the shaft to be of larger diameter than the after set, so as to get a greater
hold on the water for propelling the ship.
Figure 1 of the Drawing hereunto annexed shows a screw propeller con-
structed and arranged according to this part of my Invention, the two pairs
of blades a and b being affixed.to separate bosses, the boss a of the pair nearest
the stern of the vessel being fixed upon the screw shaft, whilst the boss b of
the hindermost pair of blades is loose thereon, and is coupled with the boss a
by projections b', which enter grooves or recesses formed around the boss a,

page_text: so as to act as a clutch when the projections come against the ends of the
grooves by the revolution of the screw ȧ, stops in the grooves being arranged
so as to cause the two pairs of blades to assume suitable relative positions
whilst in the act of propelling.
The second part of my Invention relates to side wheel propellers, which I
propose to construct of discs of suitable diameter, having the centre parts
constructed with arms and centres similar to those generally used for paddle
wheels, but having the outside rims of such discs corrugated or in a zig-zag
form, instead of being flat, in order to offer sufficient resistance when driven
through the water to propel the vessel. Either one or a series of these discs
or wheels can be used on each side of the vessel as may be required to propel
the ship, or the outside rims may be made flat, and the inside rims only be
made corrugated or in zig-zag form.
Figures 2 and 3 of the Drawing show a side view and plan of a side wheel
propeller constructed according to this part of my Invention. a, a, are two
corrugated metal rims combined and rivetted together, having narrow spaces
between them, and supported between the two flat outer rims b, b, attached by
arms 6, 61, to the central boss 6 fixed on the main shaft or axis c.
Figures 4 and 5 show a side view and. plan of a similar side wheel pro-
peller, in which arrangement two pairs of corrugated rims a, a, are combined
together, supported on arms 6¹ attached to the central boss 6%, the flat outer
rims being dispensed with. Figures 6 and 7 show a side view and plan of
one of the corrugated rims separately in which it will be seen that I prefer to
corrugate the rims tangentially to the central axis in place of radiating from
the centre, in order that the corrugated surfaces may more readily relieve
themselves from the back water.
The third part of my Invention relates to the sheathing of iron ships with
copper or other suitable sheets of metal (such sheets being perforated with
holes stamped therein) to keep them from fouling, and this I propose to do
in the following manner:-The bottom of the ship should be first well cleaned
and painted over with one or more coats of red lead, paint, or any other
suitable material to preserve the iron. I then cover the part required to be
sheathed with metal sheathing with some prepared adhesive material, such as
a mixture of tar, pitch, or other suitable substance, and upon that I lay a
coating of felt, gutta percha, or other suitable materials, and on that I again
place another coating of adhesive materials, upon which I place the perforated
metal sheathing, which is made warm on being applied to the ship's bottom,
and is pressed on to the adhesive material until it comes through the per-
forated holes made in the metal sheathing; or the holes can be filled with

page_text: short metal nails made rough, so as to set and fix themselves in the adhesive
materials. I then propose to solder, fold, or overlap the edges of the sheathing
sheets together, and to line the sides of the ship at or above the water line-
with a cleating of wood well secured to the vessel, so as to protect the covering
and adhesive materials, and to which I secure the edges of the sheathing
metal with sheathing nails. I also propose, if necessary, to place narrow
pieces of elastic substances (or strips of wood) well secured to the ship along
the ship's side at suitable distances apart, to which I fix the sheathing with
nails, in the same manner as above proposed, to the cleating.
In witness, whereof, I, the said Robert Griffiths, have hereunto set my
hand and seal, this Twenty-ninth day of November, in the year of our
Lord One thousand eight hundred and sixty-two.
Witness,
ROBERT GRIFFITHS. (L.S.)
J. G. TONGUE,
Patent Agent,
34, Southampton Buildings, W.C.