IMPROVEMENTS IN PROPELLING SHIPS OR OTHER VESSELS
Year: 1864

page_text: LETTERS PATENT to Robert Griffiths, of Mornington Road, Regent's Park,
in the County of Middlesex, Engineer, for the Invention of "IMPROVE-
TT"
Sealed the 8th November 1864, and dated the 14th May 1864.
PROVISIONAL SPECIFICATION left by the said Robert Griffiths at the
Office of the Commissioners of Patents, with his Petition, on the
14th May 1864.
"I, ROBERT GRIFFITHS, of Mornington Road, Regent's Park, in the County
of Middlesex, Engineer, do hereby declare the nature of the Invention for
"IMPROVEMENTS IN PROPELLING SHIPS OR OTHER VESSELS," to be as follows:-
This Invention has for its object improvements in arranging the position of
the screw or screws employed in propelling ships or other vessels, and is
especially applicable to those vessels which have a light draft of water. There
has hitherto been great difficulty in, or indeed no possibility of, getting an
adequate speed in proportion to the power employed in ships or vessels of
light draft when combined with broad flat bottoms and full ends, owing to the
screw, as at present arranged and employed for propelling, causing the water
to be driven away from the stern of the vessel faster than it can flow under.
the "counter" of the ship to take the place of that driven away, and also owing
to the pressure of the water per square inch on the screw blade or blades
being so small through the small amount of immersion of the screw propeller.
These causes, separately or combined, have the effect of wasting a large

page_text: proportion (in many cases as much as three-fourths) of the power employed,
the part wasted being occupied in what is known as " grinding or churning
the water."
Now my Invention is intended to obviate this difficulty and loss, and to
efficiently use up the power employed, however light the draft of water may be ;
and for the purpose of carrying out my improvements I take a screw of suit-
able diameter and mount it by suitable means attached to the stern post or
under the "counter," the axis being placed at an angle of about 45° (or other
suitable angle of inclination) to the upright stern post, the end of the screw
placed at such angle looking downwards and towards the bow of the vessel.
A short shaft passes through the screw and into the body of the vessel, and on
the end of such short shaft within the vessel suitable gearing is applied to
connect it with the steam engines or other power employed for propelling the
vessel. By placing the screw and axis at an angle as above described the water
is drawn more directly from under the vessel and a screw of much larger
diameter may be employed.
I also in some cases employ two screw propellers placed and arranged to
work at an angle as before described, one on each side of the stern post and
under each counter, by which means I am enabled to use larger screws, and
thus obtain a much better flow of water under the "counter" of vessels so
propelled. These screws are connected to the steam engines or other motive
power by bevil wheels or other suitable gearing, as is well understood, for giving
motion to screw propellers.
5.5
Another method in which I arrange and apply these screws is to take a
vessel fitted with a screw in the ordinary manner in the stern of the ship; in
addition thereto I fix two of the inclined screws arranged as above described.
under the "counters" of such vessel, the whole of the three screws being con-
nected by any suitable gearing, one form of which may be a plate or forging
having suitable bearings connecting three cranks or the three shafts with a
crank shaft on the main shaft, and thus communicating the motion to the three
shafts simultaneously; or each screw may be driven by separate engines if
desired.
The effect of this arrangement of screws is to draw the water from under-
neath the vessel, and so propel the same by means of the inclined screws, and.
also to supply water to the upright or ordinary screw, which would otherwise,
as before stated, be working with a short supply..
In place of arranging the several screw propellers at an angle, as previously
described, a proportionate advantage is obtained by employing three perpen-
licular screws with horizontal shafts as ordinarily employed, one on each quarter

page_text: at the stern of the vessel, and a central one placed. (at an angle if preferred)
in front or forward of the others and receiving its supply of water through a
channel or recess formed under the bottom of the vessel, by which arrangement
of the screws the central forward screw withdraws the water from below and
forward and drives it aft, by which means the screws at the stern are thus
partially supplied with and act upon the water thus driven aft by, the forward
screw.
The arrangement of the screws may be varied by placing the two screws.
forward (one under each "quarter") and the central screw at the stern, of
the vessel, the water driven aft by the two screws will thus partially supply the
central screw placed at the stern with water; but I prefer to employ the other
arrangements herein described.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Robert Griffiths in the Great Seal Patent Office on the
14th November 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
GRIFFITHS, of Mornington Road, Regent's Park, in the County of Middlesex,
Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fourteenth day of May, in the year of our Lord
One thousand eight hundred and sixty-four, in the twenty-seventh 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 there-
after 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 "IMPROVE-
MENTS IN PROPELLING SHIPS OR OTHER VESSELS," upon the condition (amongst
others) that I, the said Robert Griffiths, my executors or adininistrators, 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 performed, and cause the same to be filed
in the Great Seal Patent Office within six calendar months next and im-
mediately after the date of the said Letters Patent.

page_text: 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 performed,
to be particularly described and ascertained in and by the following statement
thereof, that is to say:
This Invention has for its object improvements in arranging the position of
the screw or screws employed in propelling ships or other vessels, and is
especially applicable to those vessels which have a light draft of water. There
has hitherto been great difficulty in getting an adequate speed in proportion to
the power employed in ships or vessels of light draft when combined with
broad flat bottoms and full ends, owing to the screw, as at present arranged and
employed for propelling, causing the water to be driven away from the stern of
the vessel faster than it can flow under the "counter" of the ship to take the
place of that driven away, and also owing to the pressure of water per square
inch on the screw blade or blades being so small though the small amount of
immersion of the screw propeller. These causes, separately or combined, have
the effect of wasting a large proportion of the power employed, the part wasted
being occupied in what is known as "grinding or churning the water."
Now my Invention is intended to obviate this difficulty and loss, and to
efficiently use up the power employed, however light the draft of water may be,
and for the purpose of carrying out my improvements I take a screw of
suitable diameter and mount it by suitable means attached to the stern post or
under the "counter," at an angle of about 45° (or other suitable angle of
inclination) to the upright stern post, the end of the screw placed at such
angle looking downwards and towards the bow of the vessel. A short shaft
passes through the screw and into the body of the vessel, and on to the end of
such short shaft within the vessel suitable gearing is applied to connect it with
the steam engines or other power employed for propelling the vessel. By
placing the screw at an angle as above described, the water is drawn more
directly from under the vessel, and a screw of much larger diameter may be
'employed than by placing the screw in a vertical position at the stern in the
ordinary manner.
And in order that this part of my Invention may be clearly understood
and readily carried into practice, I will proceed to describe the Drawings
hereunto annexed.―
:
DESCRIPTION OF THE DRAWINGS.
Figure 1 shows a longitudinal diagram or outline of the stern of a ship
or vessel, having a screw propeller a applied thereto, and placed at an
angle of 45° from the stern towards the bow or forepart of the vessel in

page_text: being broad, and
The stern of the
accordance with this part of my improvements. The shaft or axis a', on
which the screw a is mounted, passes down through the bottom of the vessel,
and is partly surrounded by and revolves in a suitable stuffing box or water-
tight casing, and on the upper end of the shaft or axis a' a bevil toothed
wheel or pinion a² is fixed, the teeth of which engage with a bevil toothed
wheel b¹ fixed on the main horizontal shaft or axis b, mounted in suitable bearings
within the hull of the ship or vessel, rotary motion being communicated to the
shaft 6 by a steam engine or other motive power, as is. well understood in
giving motion to the axes of ordinary screw propellers. The form of the screw
propeller a may be varied, but I prefer the form of the one shown in the
Drawing, the root of the blades near the shaft or axis a
gradually diminishing in width towards the outer extremity.
vessel, underneath which the screw propeller is arranged to revolve, may if pre-
ferred be hollowed out or suitably formed for having a screw propeller applied
thereto, and placed at an angle as indicted by the Drawing at Figure 2,
the form and position of which may however be greatly varied without
departing from the peculiar character of this part of my Invention, I also in
some cases employ two screw propellers; placed and arranged to work at an
an angle as previously described, one on each side of the stern post and under
each "counter," by which
means
I am enabled to use larger screws, and thus
obtain a much better flow of water under the "counter" of vessels so propelled.
These screws are connected to the steam engines or other motive power by bevil
wheels, or by other suitable gearing, as is well understood, for giving motion
to screw propellers.
Another method in which I arrange and apply these screws is to take a vessel
fitted with a screw in the ordinary manner in the stern of the ship, and in addi-
tion thereto I fix two of the inclined screws, arranged as above described, under
the "counters" of such vessel, the whole of the three screws being connected
by any suitable gearing, one form of which may be a plate or forging, having
suitable bearings connecting three cranks on the three shafts with a crank on
the main engine shaft, and thus communicating the motion to the three shafts
simultaneously, or each screw may be driven by separate engines if desired.
The effect of this arrangement of screws is to draw the water from underneath
the vessel and so propel the same by means of the inclined screws, and also to
supply water to the upright or ordinary screw, which would otherwise, as before
stated, be working with a short supply.
I have not thought it necessary to show Drawings of the two arrangements
of screw propellers placed at an angle as previously described, as a competent
engineer will readily apply the same to a ship or vessel, in accordance with

page_text: my Invention, aided by the description herein given of other arrangements of
screw propellers of similar character.
In place of arranging the several screw propellers at an angle as previously
described, a proportionate advantage is obtained by employing three perpen-
dicular screws (with horizontal shafts as ordinarily employed), one on each
quarter at the stern of the vessel and a central one placed (at an angle if
preferred) in front or forward of the others, and receiving its supply of water
through a channel or recess formed under the bottom of the vessel, by which
arrangement of the screws the central forward screw withdraws the water
from below and forward and drives it aft, by which means the screws at the
stern are thus partially supplied with and act upon the water thus driven aft
by the forward screw.
Figures 2, 3, 4, and 5 show diagrams of part of the stern of a vessel having
three screw propellers applied thereto arranged according to my Invention as
previously described.
The screws A, B, are placed at the stern, and are arranged to work in a
horizontal position in the ordinary manner, as shown, whilst the central screw
C is placed at an angle, forward or in advance of the others in a channel or
recess formed under the bottom of the vessel, by which arrangement of the
screw propellers the central forward inclined screw will withdraw the water
from below the fore part of the vessel, and by driving it aft the screws at the
stern will be rendered more effective by having a good supply of water to act
upon.
In the arrangement shown by Figures 2, 3, 4, and 5, motion is communi-
cated to the three screw propellers A, B, C, by means of a crank D', on the
main driving shaft, which crank is connected to a crank pin on the plate or
forging D, to which the crank pins of the three cranks A¹, B¹, C', are also
connected, and thus transmit the motion to the axes of the three screw pro-
pellers, which however may, if preferred, be driven by separate independent
engines.
1
Figures 6, 7, and 8 show an arrangement of three screw propellers similar
to the arrangement last described and shown by Figures 2, 3, 4, and 5, except
that the central forward screw shaft is placed in a horizontal position, with a
vertical screw like those at the stern, by which arrangement of the screws a
proportionate advantage is obtained, but we prefer to place the central screw
shaft in an inclined position, as shown by Figures 2, 3, 4, and 5.
The axes of the three screw propellers, arranged as previously described
according to this part of my improvements, may be driven by toothed gearing
as shown, or otherwise, or by separate engines if desired.

page_text: The arrangement of the three screw propellers employed in accordance
with this part of my Invention may be varied by placing the two screws
forward (one under each "quarter" and the central screw at the stern of the
vessel, the water driven aft by the two screws will thus partially supply the
central screw placed at the stern with water.
Figures 9, 10, and 11, show diagrams of three screw propellers arranged
in the manner previously described, the nature of which will be readily under-1
stood on examining the Drawings, aided by the previous description of similar
arrangements of three screw propellers, according to my Invention.
Having thus described the nature of my improvements in propelling vessels,
I would have it understood that I do not confine myself to the exact details
herein described so long as the peculiar character of my Invention be retained;
but what I claim is,-
First, the arranging of screw propellers to act in an inclined position or
at an angle to the keel of the vessel, as herein described.
Secondly, I claim the improved modes of propelling vessels by means of
three screw propellers, as herein described.
In witness whereof, I, the said Robert Griffiths, have hereunto set my
hand and seal, this Eleventh day of November, in the year of our
Lord One thousand eight hundred and sixty-four.
Witness,
GEO. H. BIRKBECK,
Engineer & Patent Agent,
34, Southampton Bldgs.,
Chancery Lane.
ROBT. GRIFFITHS. (L.S.)