IMPROVEMENTS IN MACHINERY FOR PROPELLING VESSELS
Year: 1877

page_text: LETTERS PATENT to John Moysey, of Leytonstone, in the County of Essex,
for the Invention of "IMPROVEMENTS IN MACHINERY FOR PROPELLING
VESSELS."
Sealed the 6th October 1877, and dated the 23rd July 1877.
PROVISIONAL SPECIFICATION left by the said John Moysey at the Office
of the Commissioners of Patents on the 23rd July 1877.
JOHN MOYSEY, of Leytonstone, in the County of Essex.
MACHINERY FOR PROPELLING VESSELS."
"IMPROVEMENTS IN
This Invention has for its object improvements in machinery for propelling
vessels.
Where the screw is employed as an auxiliary in vessels which mainly depend on
sails for their propulsion, it is of much importance to reduce, as far as possible, the
resistance offered to the progress of the vessel under sail by the screw and parts in
connection therewith. For this purpose I form a cavity or chamber to receive the
screw when it is out of use. This cavity or chamber I arrange immediately in
front of the working position of the screw behind the stern post. The screw shaft
is made to slide longitudinally for the purpose of drawing the screw forward into
this chamber or cavity when it is not required for use. The blades of the screw are
able to be feathered, or turned on edge, which reduces the size requisite in the
chamber or cavity in which the screw is to be housed.
I sometimes employ a shutter or filling piece to close the screw opening when it
This shutter
is left vacant by the screw having been drawn forward out of use.
or filling piece may be arranged to work in a vertical trunk in the stern of
the vessel, or in other ways, it may be placed in the screw opening or removed
when necessary.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Moysey in the Great Seal Patent Office on the 22nd January
1878.
JOHN MOYSEY, of Leytonstone, in the County of Essex.
MACHINERY FOR PROPELLING VESSELS."
"IMPROVEMENTS IN
This Invention has for its object improvements in machinery for propelling vessels.
Where the screw is employed as an auxiliary in vessels which mainly depend on
sails for their propulsion, it is of much importance to reduce, as far as possible, the
resistance offered to the progress of the vessel under sail by the screw and parts in
connection therewith. For this purpose I form a cavity or chamber to receive the
screw when it is out of use. This cavity or chamber I arrange immediately in
front of the working position of the screw, behind the stern post. The screw shaft
is made to slide longitudinally for the purpose of drawing the screw forward into
this chamber or cavity when it is not required for use.
The blades of the screw are
able to be feathered, or turned on edge, which reduces the size requisite in the
chamber or cavity in which the screw is to be housed.
I sometimes employ a shutter or filling piece to close the screw opening when it
is left vacant by the screw having been drawn forward out of use. This shutter
or filling piece may be arranged to work in a vertical trunk in the stern of
the vessel, or in other ways, it may be placed in the screw opening or removed
when necessary.
The annexed sketches show the stern of a ship fitted according to my Invention.
In Figure 1 the screw is represented in position for propelling; and in
Figure 2, it is represented feathered and drawn back into the chamber prepared to
receive it.
It is unnecessary that I should describe any special means of feathering the
screw, for feathering screws are well known and in public use, neither is it
necessary that I should describe the means for moving the screw shaft in a longitu-
dinal direction, for this has been commonly done where ships have been fitted with
lifting screws.
In the construction of the ship itself there is but little deviation from the ordinary
practice, the screw opening is made larger in the fore-and-aft direction, and the front
part of it is enclosed by plating being carried over it on the two sides, but it is left
open in rear for the propeller when feathered to enter and to leave the chamber or
cavity.
If desired a bearing may be provided upon the rudder post to receive the end of
the screw shaft; if such a bearing be employed, it should be made somewhat conical,
and the end of the screw shaft should be of a corresponding form. The shaft when
drawn forward leaves this bearing, but in consequence of the conical form given
to the parts enters it again when the shaft is thrust back to bring the screw to its
working position.
As already mentioned shutters may be provided completely to close the screw
aperture when the feathered screw has been drawn forward into the chamber or
cavity.
Having thus described the nature of my said Invention, and the manner of
performing the same, I would have it understood that I claim the arrangement of
machinery for propelling vessels, substantially as described, consisting of a feathering
screw propellor mounted upon a screw shaft capable of being drawn forward, and
of a chamber immediately in rear of the stern post to receive the feathered screw,
substantially as described.
In witness whereof, I, the said John Moysey, have hereunto set my hand
and seal, this Twelfth day of January, in the year of our Lord One thousand
eight hundred and seventy-eight.
JOHN MOYSEY. (L.S.)