Im- PROVEMENTS IN SCREW PROPELLERS FOR STEAM SHIPS OR VESSELS
Year: 1871

page_text: LETTERS PATENT to Joshua Horton, of the Town of Birmingham,
in the County of Warwick, Engineer, for the Invention of “Im-
PROVEMENTS IN SCREW PROPELLERS FOR STEAM SHIPS OR VESSELS."
Sealed in pursuance of an Order of the Lord Chancellor the 29th August
PROVISIONAL SPECIFICATION left by the said Joshua Horton at the
Office of the Commissioners of Patents, with his Petition, on the
17th February 1871.
I, JOSHUA HORTON, of the Town of Birmingham, in the County of
5 Warwick, Engineer, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN SCREW PROPELLERS FOR STEAM SHIPS. OR VESSELS," to be
as follows, that is to say:-
.
This said Invention has reference to certain improvements to be
applied to any or all of the various forms and constructions of screws
used for the propulsion of steam ships or vessels, whereby much power
heretofore apparently lost or unprofitably expended will be saved and

page_text: utilized, and a greater speed given to the ship with the same or an equal
expenditure of power than heretofore.
And the nature of this said Invention substantially consists in forming
on or attaching to the acting faces of the said screws or their blades, at
various distances out from and concentric to their axis or shaft, one,
two, three, or more thin narrow rings, or webs, or segmental feathers,
by preference, projecting parallel to and at various heights to suit their
number and size of the screw, as, say from two to six inches out from
the said faces, having the inner surface of these rings or segments by
preference nearly concentric to the axis, and at right angles to the radii
of the said acting screw surfaces.
Although in some cases these two surfaces may be made to glide or
run into each other by a curve or hollow fillet, the petitioner does not
claim the placing of such rings or segments at the outer periphery of
the screw, as he is aware that has been done before without success, but
he believes that his new mode of using and placing the rings or feathers
in a number distributed at distances over the surfaces of the screws
effectually prevents the centrifugal action of the water and sends it out
nearer the parallel direction of the keel and of the propulsion of the
ship than heretofore.
SPECIFICATION filed in pursuance of the conditions of the Letters
Patent, and of an Order of the Lord Chancellor, by the said
Joshua Horton in the Great Seal Patent Office on the 30th August
1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOSHUA 2
HORTON, of the Town of Birmingham, in the County of Warwick,
Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Seventeenth day of February, in the year
of our Lord One thousand eight hundred and seventy-one, in the thirty- 3
fourth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Joshua Horton, Her special licence that I,
the said Joshua Horton, my executors, administrators, and assigns, or
such others as I, the said Joshua Horton, my executors, administrators,
and assigns, should at any time agree with, and no others, from time to 3

page_text: 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 SCREW PROPELLERS
FOR STEAM SHIPS OR VESSELS," upon the condition (amongst others) that
I, the said Joshua Horton, my executors or administrators, by an instru-
ment 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 on or before
the Thirty-first day of August One thousand eight hundred and seventy-
one.
NOW KNOW YE, that I, the said Joshua Horton, do hereby declare
the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by
the following statement in writing, reference being had to the accom-
panying Sheet of Drawings, and to the letters and figures marked
thereon, that is to say:-
My said Invention has reference to certain improvements to be
applied to any or all of the various forms and constructions of screws
used for the propulsion of steam ships or vessels, whereby much power
heretofore apparently lost or unprofitably expended will be saved and
utilized, and a greater speed given to the ship with the same or an equal
expenditure of power than heretofore.
And the nature of my said Invention substantially consists in forming
on or attaching to the acting faces of the said screws or their blades, at
various distances out from and concentric to their axis or shaft, one,
two, three, or more thin narrow rings or webs or segmental feathers, by
preference projecting parallel to and at various heights to suit their
number and size of the screw, as, say from two to six inches out from
the said faces, having the inner surface of these rings or segments by
preference nearly concentric to the axis and at right angles to the radii
of the said acting screw surfaces.
Although in some cases these two surfaces may be made to glide or
run into each other by a curve or hollow fillet, I do not claim as novel
the placing of such rings or segments at the outer periphery of the
screw, as I am aware that has been done before without success; but I
believe that my new mode of using and placing the rings or feathers

page_text: in a number distributed at distances over the surfaces of the screws
effectually prevents the centrifugal action of the water, and sends it out
nearer the parallel direction of the keel and of the propulsion of the
ship than heretofore.
Having thus described the nature of my said Invention I will now
proceed to describe the manner of performing the same by reference to
the several Figures on the explanatory Sheet of Drawings, which I have
hereunto appended for the purpose of showing the best modes and
means I am at present aware of for so doing, the same reference letters
indicating the same or like parts in all the Figures.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a side elevation and Figure 2 is an "aft" end elevation
with the lower half or blade in vertical section through the centre at
right angles to Figure 1 of a large screw propeller B, B, C, secured
on the after end of its propeller shaft D, and having my said new or
improved ribs, webs, or feathers A, A', applied thereto for the purposes
stated, and preventing the centrifugal action of the water forced from
the acting surfaces of the blades B, and causing it to pass off in the
more parallel direction or line of propulsion or keel, and sufficient to
show or illustrate the modes and means of performing my said Inven-
tion; Figures 3, 4, and 5 being a longitudinal plan and two horizontal
sections of the same propeller respectively taken on the blue lines 1 --- 1,
22, and 33 in Figures 1 and 2, and corresponding to the position
of the screw in Figure 1; while Figures 6 and 7 are vertical elevations
of the forward and back propelling faces 6 and 6' of one of the screw
blades B as looking on them from the "aft" and forward direction on
the angle lines of the red arrows 4 and 5 in Figure 4 and 5, all respec-
tively so as to show the full width of these acting faces b, b', and length
of the spiral segmental feathers A, A', on them, and to make their
construction and projection in these simple face views more evident
than they are in the foreshortened views, Figures 1 and 2.
Figures 8 and 9 are similar "aft" and front angled side views of the
forward and back propelling faces b, b', of one blade B of a screw similar
to Figures 6 and 7, and showing a slightly different modification or
construction of the feathers A, A', from that shown in these Figures.
Referring to Figures 1 to 7 it will be seen that the screw or angle of
the thread (or blades B) is right-handed, so that it is turned from left

page_text: to right on the upper side looking from the "aft" end D, Figure 2, for
propelling the ship "ahead,” as indicated by the black arrows, and vice
versa for "backing,” as indicated by the blue arrows; and the general
form and shape of the body B and screw surfaces b, b', of the two
blades B, and their hollow ball eye or boss C, and mode of fixing same
to the propeller shaft D, are all so far of a usual type and construction,
and is here reproduced and delineated from the screw of a large steam
ship which made a long voyage with it as an ordinary screw, and
afterwards fitted with my improved feathers A, A', from which it was
computed and considered that the ship made from ten to twenty per
cent. greater speed throughout the voyage with my improvements than
the same screw did without them. The two forward acting or propelling
surfaces 6 of the blades B have six of my new or improved thin screw
or helical segmental feathers A cast or formed on the main central body
part, generated at equal distances of about twelve inches apart annularly
from the boss C outwards to within some six or eight inches of the
outer edge or circumference of the blade B, and two like feathers A¹ are
similarly formed and disposed near the boss C on the back acting and
propelling face 6', seen best in Figures 1 and 7; but there may be more
or fewer of these feathers either so formed or made separately, and
attached by screws or otherwise to these faces b, b', respectively. These
feathers A, A, are preferred to be made thin at the outer edge, and a
little thicker on the back or outer perimeter towards their root, where
they join the acting surfaces b, b', (of the blades B) from which they
are preferred to project nearly parallel in height therefrom, and have
their inner acting surfaces at right angles thereto, all as seen particularly
in Figures 2, 3, 4, and 5. Although they might vary in these respects
considerably without injury and even with advantage to their useful
effect and action in some cases, as indicated in the edge and horizontal
sections 2 and 6*, where instead of the inner acting surfaces of the
feathers A, A', being made to join the acting surfaces b, 61, of the
blades B at right angles to the radii generating the latter surface, they
are shown and made to glide or run into each other by a curve or hollow
fillet x, seen particularly in Figure 2*, so that the water would glide
freely round from the radial screw surfaces 6, 61, (at right angles) to
the parallel line of propulsion and the acting inner surfaces of the
feathers A, A', as indicated by the blue darts x' in this Figure; and in
some cases the feathers A, A', might with advantage be made gradually
narrower in depth as they recede each outwards towards the circum-

page_text: ference or point of the blade, as also indicated in this Figure; and
perhaps in some cases also with some advantage they might be made
narrower or less in depth towards their after or tail ends a¹, as indi-
cated in the horizontal section 6ª. The extreme after end and journal
of the propeller shaft D is indicated at D³, so that when it and the
propeller B, B, C, is turned in the direction of the black arrows
the surfaces 6 and their six feathers A. act so as to propel the ship and
screw, or force the water "aft;" and, conversely, when turned in the
opposite direction, as indicated by the blue arrows, the faces 6' and their
two feathers A¹, near the boss C, propel the ship backwards or "astern;"
and thus in both these cases the ends marked a of the feathers A, A¹,
indicate the entering or advance ends, and the ends marked a¹ indicato
the after or following tail ends of these feathers A, A', in their respective
"forward" and "backing" action, as lettered and shown particularly
by the black and blue arrows in the full face views of one blade,
Figures 6 to 9. It will be seen that these feathers A, A¹, or their said
acting surfaces nearest the centre, in the example or application shown
in Figures 1 to 7, are formed concentrically or parallel to the axis, that
is, having their leading and tail or back ends a and a¹ equidistant from
the axis of the propeller shaft D, and as indicated also by the red
lines a in Figures 8 and 9, or as generated in the form of a parallel
helix, or a segment of this; but I have also found that the entering
end a of two, three, or more of these new segments A, A³, nearest the
centre may with advantage be placed gradually a little nearer the centre
as they approach the boss (as indicated at a², Figures 8 and 9), retaining
their following or tail ends a¹ at the said equal or regular distances a",
thus generating these feathers A, A', (as they approach the centre) as
segments of increasing conoidal helixes, with greater angles on the
leading side or end a towards the centre or boss.
The action and advantages of screw propellers having my new or
improved segments A, A¹, formed or attached thereto although they
must give some little increased friction in the water), over the ordinary
plain screws without them are that they prevent the water flowing
outwards in a radial or centrifugal manner and direction along the
surface of the oblique blades (with great advantage near the boss and
broad part of the body B¹, where their surfaces have least propelling
power, and consequently most centrifugal action), by conducting or
diverting it along the oblique surface and out from it along their own

page_text: inner acting cylindrical or conoidal surface a* at the right angles formed
by the segment with the radii of the acting surfaces 6, 6', of the screw,
as indicated by the blue darts at a¹ in Figures 2, 2*, and 3.
The arrangement shown in Figures 8 and 9, in addition to the said
action, directs the water to a limited extent outwards from the parts
nearest the boss to where the circumference is greater, and the angle of
the blades B have a more direct propelling effect, so that the column
of water displaced by the large boss and caught by the flat of the
blades B near it is accelerated in its motion backwards in the line or
direction of propulsion with less loss of friction and power than by
the use of screws as heretofore constructed, and thus much power is
saved and utilized in direct propulsion by my said improvements and
Invention, as herein specified.
Having thus described the nature of my said Invention, and the
manner of performing the same, I would have it understood that what
I claim is, the use of one, two, three, or more annular or segmental
feathers generated as parallel or conoidal helical acting surfaces at
various distances over the acting faces of screw propellers for steam
ships or vessels, substantially as herein described.
In witness whereof, I, the said Joshua Horton, have hereunto set
my hand and seal, this Twenty-ninth day of August, in the year
of our Lord One thousand eight hundred and seventy-one.
Witness,
W. R. M. THOMSON,
Patent Agent,
20, Buchanan Street,
Glasgow.
JOSHUA HORTON. (L.S.)