IMPROVEMENTS IN PRO- PELLERS FOR SHIPS AND BOATS
Year: 1858

page_text: LETTERS PATENT to John Robb, of Aberdeen, in the County of Aberdeen,
North Britain, Merchant, for the Invention of "IMPROVEMENTS IN PRO-
PELLERS FOR SHIPS AND BOATS."
Sealed the 12th April 1859, and dated the 25th October 1858.
PROVISIONAL SPECIFICATION left by the said John Robb at the Office
of the Commissioners of Patents, with his Petition, on the 25th October
1858.
I, JOHN ROBB, of Aberdeen, in the County of Aberdeen, North Britain,
Merchant, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN PROPELLERS FOR SHIPS AND BOATS," to be as follows:-
This Invention relates to a peculiar construction and arrangement of direct-
acting submerged propeller applicable to ships and boats either for sea or
inland navigation. The propeller, according to this Invention, consists of a
horizontal shaft or bar, having a reciprocating motion imparted to it in the
direction of its longitudinal axis, which motion may be derived either from a
steam engine or other driving power. To the outer end of this shaft or bar is
secured or formed a V-shaped block of metal, having the narrow end towards
the ship; to this narrow end is hinged on either side a vertical wing or float,
which wings are free to open out at right angles to the propeller bar or shaft
or to close against the sides of the V piece before referred to, but at the same

page_text: time to be kept just sufficiently open to expand when urged against the water.
A transverse cross-bar or stop fitted to the propeller shaft or bar behind tho
wings serves as a rest or stop for the wings to bear against when open for
being pushed through the water. The action of this propeller, consequently, is
perfectly direct upon the body of the water, the wings alternately opening and
closing as the propeller shaft or bar moves outwards from or inwards towards
the ship. In some cases one float or wing only may be used in place of two
as previously described. These propellers may be applied either to the bows,
stern, or sides of a ship or boat, as may be found most convenient or suitablo
for the kind of navigation required.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Robb in the Great Seal Patent Office on the
23rd April 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
ROBB, of Aberdeen, in the County of Aberdeen, North Britain, Merchant,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-fifth day of October, in the year of our Lord One
thousand eight hundred and fifty-eight, in the twenty-second year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
John Robb, Her special license that I, the said John Robb, my executors,
administrators, and assigns, or such others as I, the said John Robb, my
executors, administrators, or 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 PROPELLERS FOR
SHIPS AND BOATS," upon the condition (amongst others) that I, the said John-
Robb, by an instrument in writing under my hand and seal, 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 immediately
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said John Robb, do hereby declare the
nature of my said Invention, and in what manner the same is to be

page_text: performed, to be particularly described and ascertained in and by the following
statement, reference being had to the accompanying Drawings, and to the
letters and figures marked thereon, that is to say:-
My said Invention relates to a peculiar construction and arrangement of
direct-acting submerged propeller applicable to ships and boats and other
floating craft, either for sea or inland navigation. The propeller, according to
this Invention, consists of a horizontal shaft or bar, having a reciprocating
motion imparted to it in the direction of its longitudinal axis, which motion may
be derived either from a steam engine or other driving power. To the outer
end of this shaft or bar is secured or formed a V-shaped block of metal, having
the narrow end towards the ship; to this narrow end is hinged on either side
a vertical wing or float, which wings are free to open out at right angles or
nearly so to the propeller bar or shaft, or to close against the sides of the
V piece before referred to, which latter keeps them just sufficiently open to
cause them to expand when urged against the water. A transverse cross-bar
or stop fitted to the propeller shaft or bar behind the wings serves as a rest or
stop for the wings to bear against when open in readiness for being pushed
through the water. The action of this propeller consequently is perfectly
direct upon the body of the water, the wings opening and closing as the
propeller shaft or bar moves outwards from or inwards towards the ship. In
some cases one float or wing only may be used in place of two as previously
described. These propellers may be applied either to the bows, stern, or sides
of a ship or boat, as may be found most convenient or suitable for the kind of
navigation required.
And in order that iny said Invention may be fully understood, I shall now
proceed more particularly to describe the same, and for that purpose 1 shall
refer to the several Figures on the Sheet of Drawings hereunto annexed, the
same letters of reference indicating corresponding parts throughout all the
Figures.
Figure 1 of the annexed Sheet of Drawings represents a sile elevation of
one form of my improved propeller detached, and Figure 2 is a corresponding
sectional plan of the same taken through 1-2.
The wings or floats A, A, are shewn closed, that is, in the position which
they would assume during the inward or back stroke of the propeller shaft B,
whilst the dotted lines represent the positions of the floats or wings when
expanded or in the act of exerting their force against the water during the
outward stroke of the propeller shaft. These floats or wings, which may be
composed of wood or metal, or both, are hinged at C, C, to the V-shaped

page_text: block D, fast on the end of the propeller shaft, and made either in one piece
with or separate from the metal boss E, which is also fixed on to the end of the
propeller shaft. F, F, are transverse arms or stops projecting at right angles,
or nearly so, with the propeller shaft, which arms may also be made in one
piece with the boss E, and serve as stops or supports for the hinged floats or
wings to bear against when fully open, as shewn by the dotted lines in
Figure 2. For end propellers on a large scale it will be found advantageous
to have more than one stop or supporting bar, so that the floats will have a
bearing at two or more points when open. The V-shaped block D fitted on to
the extremity of the propeller shaft, serves to maintain the floats when closed
at a slight angle to the shaft, so that they will readily open or expand again
by the resistance of the water when the propeller shaft again moves outwards.
The propeller above described may be placed either at the stern or bows, or at
both ends of a ship or boat, and may be composed of any convenient number
of floats from one upwards.
.
Figures 3 and 4 represent respectively a side elevation and plan of a slightly
modified form of propeller, wherein the floats or wings A are hinged one
within the other, both working round one pin or common centre, in place of
each wing or float having a separate centre of its own, as in the first described
arrangement. By this means the floats or wings offer a much smaller
resisting surface to the water during the back stroke, as will be obvious on
comparing the two arrangements in the Drawings. A considerable saving of
metal and consequently increased lightness is also obtained by reducing the
V-shaped block D of Figures 1 and 2 to two simple projections d, d, at the top
and bottom respectively of the arms to which the floats are hinged, which
arms I bevel off to a knife edge at the back, as shewn in Figure 4, to obviate
as much as possible all unnecessary back resistance.
In some cases the end propeller may be formed like a cross, one part of the
cross serving to support the backs of the floats, and the other having pro-
jections near the middle, through which and through the floats a pin is passed,
which thus serves to fix the floats, and to secure the head of the propeller to
the propeller shaft.
In the arrangement or modification illustrated in side elevation at Figure 5,
and in corresponding plan at Figure 6, the floats or wings A, which are here
shewn composed of wood in lieu of metal as previously shewn, are hinged
to one side only of the propeller shaft B in place of having a float on either
side of such shaft as herein-before described and illustrated in Figures 1, 2, 3,
and 4. This latter modification is intended to be worked at the sides of ships.

page_text: The shaft B slides to and fro longitudinally in the bearings H, H, secured to
the hull of the ship some distance below the light water line, so that the
propellers in all cases will be entirely submerged. In front of each float or
wing is fitted on to the shaft an inclined projection D for the purpose of keeping
the floats at a slight angle or just sufficiently open when in their closed position
as to enable them readily to open fully when the resistance of the water acts
against them on the forward stroke of the shaft. The arms or stops F, F, are
bolted or otherwise secured to the propeller shaft, which shaft, for the sake of
lightness and of affording a more ready means of hinging the floats or wings,
is made double or in the form of an open frame at the part where the floats
are connected, as is clearly shewn at Figure 5. Figure 7 represents a side
elevation, and Figure 8 a corresponding plan of a similar propeller com-
posed entirely of metal, the floats being each made from one piece of metal,
and having each a stop D fitted or formed thereon in lieu of the inclined
projection D referred to in the last described modification.
I may here
observe that I do not confine myself to the precise arrangements and con-
structions illustrated by my Drawings, as, for example, it is obvious that the
stops or arms F, F, might be fixed to the backs of the floats themselves in
place of to the propeller shaft, and made to bear upon the opposite sides of
such shaft when the floats are sufficiently open. And, moreover, the V-shaped
block D might be dispensed with and projections formed on the front faces of
the floats for the purpose of keeping them opened at a slight angle when in their
comparitively closed position, but the arrangements which I prefer to use are
those which I have herein-before described in reference to the illustrative
Figures on the Sheet of Drawings annexed.
Having now described and particularly ascertained the nature of my said
Invention, and the manner in which the same is or may be used or carried
into effect, I would observe in conclusion that I do not confine or restrict
myself to the precise details or arrangements which I have had occasion to
describe or refer to, as variations may be made therefrom without deviating
from the principles or main features of my said Invention; but what
I consider to be novel and original, and therefore claim as the Invention
secured to me by the herein-before in part recited Letters Patent, is,
First, the general constructions, arrangements, and combinations of ships'
propellers, as herein-before described and illustrated in my Drawings.
Second, the constructing of submerged propellers, applicable to the stern,
bows, and sides of ships and boats of all kinds, by hinging one or more floats
or wings to a bar or shaft, such bar or shaft being fitted with transverse stops

page_text: or arms for supporting the floats or wings when in an open or expanded state,
and also fitted with suitable appliances for maintaining such floats or wings at
a slight angle to the propeller bar or shaft when closed, the whole having a
a longitudinal reciprocating motion imparted to it by steam or any other
Dower.
or arms for supporting the floats or wings when in an open or expanded state,
and also fitted with suitable appliances for maintaining such floats or wings at
a slight angle to the propeller bar or shaft when closed, the whole having a
a longitudinal reciprocating motion imparted to it by steam or any other
Dower.
In witness whereof, 1, the said John Robb, have hereunto set my hand
and seal, this Eighteenth day of April, One thousand eight hundred and
fifty-nine
JOHN ROBB. (L.S.)