Improvements in the Feathering and Sheathing of Steam Ship Propellers, also in Means for Altering the Angle of Propeller Blades.
Year: 1895

page_text: Date of Application, 21st Nov., 1895
Complete Specification Left, 21st Aug., 1836-Accepted, 3rd Oct., 1896
PROVISIONAL SPECIFICATION.
Improvements in the Feathering and Sheathing of Steam Ship
Propellers, also in Means for Altering the Angle of Propeller
Blades.
I, JOHN FERGUSON, of West Pier, Leith, N.B. and 14 St. George's Square,
London, S.W., Engineer and Shipbuilder, do hereby declare the nature of this
invention to be as follows:-
This invention relates to improvements in the feathering and sheathing of steam
ship propellers; also in means for altering the angle of propeller blades and my
improvements are applicable to propellers with two, three or more blades.
In the carrying out of my invention I mount or pivot the blades on pins at a
distance from the centre of the boss and by a rack and pinion, operated from
inboard by a shaft within the main shaft. I cause the blades to fold down from a
vertical or outspread position to a fore and aft or feathered position the tips of the
blades being drawn closely together. The said shaft within the main shaft may
be operated by any suitable screw gear; or by any equivalent mechanical arrange-
ment for operating the inner shaft. Also instead of a rack and pinion within the
boss may employ levers or cams. When in this position the blades are so
arranged that they occupy little more space than the boss of the propeller in a fore
and aft direction. This being so a recess is constructed in the stern post of the
vessel (or at the sides if more convenient or for twin screws) with an orifice large
enough to easily take in the propeller boss and of a fore and aft length to take
in the length of the blades when feathered. By a screw lever or other arrange-
ment, the engine or other motive power with shafting attached, can then be moved
forward a sufficient length to bring the complete propeller blades into the ship and
out of sight.
An alternative arrangement is where the engine would be fixed in the ship when
it would work into a geared wheel sliding on a keyway on the shaft which would
be moved fore and aft by screw, lever or otherwise.
If an alteration in the pitch of the blades was required, this would be effected
by a worm or screw motion or projection or cam on the end of the inner sliding
shaft in the boss whereby the blades could be turned to vary the angle.
Dated this 20th day of November 1895.
JOHNSONS,
115 St. Vincent Street, Glasgow, Applicant's Agents.
COMPLETE SPECIFICATION.
Improvements in the Feathering and Sheathing of Steam Ship
Propellers, also in Means for Altering the Angle of Propeller
Blades.
I, JOHN FERGUSON, of West Pier, Leith, N.B. and 14 St. George's Square,
London S.W. Engineer and Shipbuilder, 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 relates to improvements in the feathering and sheathing of steam

page_text: ship propellers, and also in the means for altering the angle of the propeller blades,
and has for its object to provide a vessel with a propeller which, instead of being
immovably fixed in one position at a set distance from the rudder or stern post cau
be drawn into or towards the body of the ship, so that when the vessel is sailing,
moving among ropes, nets etc. or in any position where an exposed propeller might
be disadvantageous, it is entirely out of sight, offers no hindrance to the progress
of the vessel and shews no projection that would catch any object floating or passing
alongside.
But in order that my invention may be more readily understood and easily carried
into effect I will proceed to describe the same with reference to the accompanying
drawings in which
Figure 1 is an elevation.
Figure 2 a plan.
Figure 3 an end view and
Figure 4 a detail view shewing one method of carrying out my invention.
Figure 5 is an elevation and
Figure
an end view of a modified form.
Figure 7 is an elevation.
Figure 8 an end view and
Figures 9 and 10 detail views shewing method of altering the pitch of propeller
blades
Referring to Figures 1, 2, 3, & 4 of the drawings I mount or pivot the propeller
blades A on pins a at a distance from the centre of the boss B, the inner ends of
the blades being formed with teeth a' which engage with a rack a' formed upon the
end of the shaft C which works within the outer shaft whereby upon the
pulling forward of the shaft C the blades change from a vertical or outspread
position as shewn in Figure 4 to a fore and aft or feathered position as shewn
in Figure 1.
The shaft after the blades have been feathered is free to be drawn forward
within the vessel and thus cause the propeller to enter the aperture D in the stern
post of the vessel which in this case is circular, or in the case of twin screws or
where deemed advisable corresponding apertures on each side of the ship.
In order to operate the inner shaft C which has the rack a' formed thereon, I
provide the outer shaft b within which the shaft C works, with a nut c into which
the end of the inner shaft C, which is screwed, engages; the said nut c is formed
with a collar c¹ which works in a recess in the outer shaft band is held in position
by a plate so that it is free to be revolved and operate the shaft 6 in either
direction as required.
For the purpose of drawing the propeller within the aperture in the stern post
I employ a sole plate E upon which are mounted two bearings e within which the
shaft b revolves; the shaft being operated by means of a spur or sprocket wheel e
which is secured to the shaft by means of two keys which work in slotted
keyways in such a manner that the shaft is capable of being moved longitudinally
while at the same time being revolved by the said wheel e¹.
by
The end of the said outer shaft is also mounted within a bearing F which is
capable of sliding within guides E' upon the sole plate E, and is secured therein
by means of two collars f. The said bearing F is moved backwards and forwards
a screwed shaft G the one end of which is mounted within the bearing e the
other end being mounted and secured within the bearing by a collar g¹ and
retained by a plate g; the said screw being operated by a hand wheel g³. The
bearing F when the propeller is in its exposed position is secured by means of two
pinching pins E³.
It will be readily seen from the foregoing that after the blades have been
feathered through the medium of the nut c, by operating the hand wheel g³ the
whole propeller can be easily drawn into the aperture D and vice versa.
Or in place of pivotting the propeller blades I may employ a solid propeller A

page_text: as shewn in Figures 5 and 6 fixed immovably upon the shaft b so that when desired
to sheath this propeller the shaft (which in this case is solid) is simply drawn into
the ship by means of the same apparatus as first described thereby causing the
propeller to enter the aperture D.
As this last form of propeller however necessitates a somewhat clumsy form of
stern post and aperture I may mount the blades A as shewn in Figs. 7, 8, 9 & 10
within the boss B in such a manner that their inner ends project to nearly the
centre of the boss and provide them with teeth a' which engage with teeth a²
formed upon the end of the inner shaft C whereby a rotatory motion is given to
the root of each blade which enables the blades, when the propeller is not required,
to be placed in a fore & aft position, in which position they can be drawn within
the aperture D.
The arrangement of the teeth a³ upon the end of the shaft C is such that each
blade is operated in the opposite direction to the other thereby enabling the pitch
of the blades to be altered as required, and may be employed in cases where the
propeller is not required to be drawn in but is always in an exposed position.
In place of forming the end of the shaft with teeth I may employ cams, levers
or any other equivalent, both in this case & in the propeller described in
Figures 1, 2, 3 & 4.
Also in place of the apparatus shewn for drawing in the propeller I may
employ a clutch, lever, ratchet, hydraulic or any other appliance; or I may mount
the engine or other motive power with shafting attached that it can be moved
forward a sufficient length to bring the propeller blades into the ship and thus
out of sight.
An object to which this propeller is particularly applicable is the assistance that
may be given by their being used as steering engines, in which case one might be
placed on each quarter of an ironclad or other unwieldy vessel and with an
engine applicable to both, be of the greatest service in pushing round the
vessel's stern or bow when manœuvring in confined spaces, especially at slow.
speeds.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what
claim is:
1st. The means for feathering and sheathing steam ship propellers and for
altering the angle of propeller blades, substantially as hereinbefore described and
shown in the accompanying drawings.
2nd. In means for feathering and sheathing steam ship propellers, pivotting
the propeller blades within the boss whereby they can be feathered by means of a
shaft within the outer shaft having a rack which engages with teeth upon the inner
ends of the blades and operated by a nut at the end of the shaft, or any other
mechanical equivalent, substantially as herein before described and shewn in the
accompanying drawings.
3rd. In means for feathering and sheathing steam ship propellers, the apparatus
for sheathing the propeller after the blades have been feathered substantially as
bereinbefore described and shewn in Figures 1 & 2 of the drawings.
4th. In means for sheathing steam ship propellers, the employment of a solid
propeller fixed immovably upon a solid shaft in combination with the apparatus
for sheathing propellers, shewn in Figures 1 & 2 or any other mechanical
equivalent of the same, substantially as hereinbefore described and shewn in the
accompanying drawings.
5th. In means for feathering and sheathing propellers mounting the blades
within the boss in such a manner that their pitch can be readily altered by means
of a shaft within the cuter shaft through the medium of a double ratchet engaging
with teeth upon the inuer ends of the blades, in combination or not with the
apparatus for sheathing the propeller described and shewn in Figures 1 & 2 of

page_text: the drawings or any mechanical equivalent of the same, substantially as herein-
before described and shewn in the accompanying drawings.
Dated this 20th day of August 1896.
JOHNSONS,
115 St. Vincent Street, Glasgow, Applicant's Agents.