Improvements in Screw Propellers.
Year: 1897

page_text: Date of Application, 19th July, 1897
Complete Specification Left, 4th Feb., 1898-Accepted, 16th July, 1898.
Improvements in Screw Propellers..
THOMAS MAKEPEACE, of Hawthorn Villa, Pellhurst Road, Ryde, Engineer, and
ARTHUR STRATTON FOWLES, Gentleman, of Cartrons, West Cowes, Isle of Wight,
do hereby declare the nature of this invention to be as follows:-
The propeller is made of cast, or wrought metal, it consists of a hollow -boss,
and blade in one piece, the boss is bored to fit "tail shaft" and fixed either
by feathers, keys nuts, or otherwise. The propeller is of spiral shape, forming
one complete turn, or screw, the leading and outside edges are perfectly fine
tapering from the base of the blade.
This propeller has been designed to secure a greater speed in steam vessels, as:
also to acquire more comfort for passengers, by greatly reducing the vibration.
A propeller of this type is considerably smaller in diameter than the ordinary
one of the same pitch and therefore immersed deeper, which is a very great.
advantage in a merchant steamer when "light," as there would be no part of the
screw above the water, as is often the case which means power wasted.
This propeller is totally immersed and has a better hold in the water, and that
hold maintained, because the screw is continued on to a perfect thread, and is not.
a section of screw only, as in other propellers.
The pitch is the same in every part, and not finer the farther you go.from the-
centre.
The vibration is reduced to a minimum there being no blades to lash the water,.
but a continual, steady all round pressure.
66
It is just as easy to go astern as ahead, the screw being the same on both.
sides.
Dated this 19th day of July 1807
THOMAS MAKEPEACE,
ARTHUR S. FOWLES.
We, THOMAS MAKEPEACE, Engineer, of Hawthorn Villa, Pellhurst Road, Ryde,
Isle of Wight, and ARTHUR STRATTON FOWLES, Gentleman, Cartrons, - West
Cowes, Isle of Wight, 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:-
This invention for improvements in screw propellers, has for its object to
provide a propeller having a higher efficiency that is possible with screw propellers
I Price Q77'

page_text: as at present constructed and also to reduce the vibration of the vessel, due to the
motion of the propeller, and thereby increase the comfort of passengers; and
consists essentially of a screw blade of constant pitch formed integral with a
central boss or sleeve and making one complete.revolution about it, the said boss
or sleeve being symmetrically formed and so secured to the screw shaft that either
end of the screw blade may be made, to lead as desired.
In the accompanying drawings, Fig. 1 shows a side elevation of a screw pro-
peller constructed according to this invention, Fig. 2 is an end elevation, and
Fig. 3 a longitudinal section of the same. Figs. 4 and 5 are end elevation and
section respectively of a bush for securing the screw to the screw shaft. Fig. 6
is an elevation of the stern end of a vessel fitted with a single screw, and Fig. 7
1s a similar view arranged for twin screw propellers. Fig. 8 shows a cross section
of screw blade.
A screw blade a of constant pitch is formed integral with a central boss or
sleeve band makes a complete revolution, about it. The said boss, or sleeve is
symmetrically formed each end being bored conical to fit the corresponding
conical part c of the screw shaft d. The propeller is maintained axially on its
shaft d by means of a conical bush e liáving a feather corresponding to the
feather or other key on the part of the shaft and is finally secured thereon by
means of a nut g. As both ends of the boss or sleeve b are similarly coned the
propeller can be easily reversed on its shaft if desired as will be readily under-
.stood.
In practice we prefer to proportion the cross section of screw blade as shown
in Fig. 8, that is to say to divide the blade into three parts measured radially from
the root to the edge in the proportions of -7, 8 and 6 the relative thickness of the
blade at those parts being as 4, 6 and 5 respectively as shown..
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim is:
1. A screw propeller comprising a screw blade of constant pitch formed integral
with a central boss or sleeve and making one complete revolution about it, the
said boss or sleeve being symmetrically formed substantially as described for the
purpose set forth.
2. In a screw propeller the combination of a screw blade formed with a boss or
sleeve having internal conical ends, a shaft having a conical part fitting in one
end of the said boss or sleeve and a conical bush secured on the said shaft and
fitting in the other end of the said boss or sleeve substantially as described.
3. A screw propeller blade proportioned as described and shown in Fig. 8 of
the drawings.
Dated this 4th day of February 1898