IMPROVEMENTS IN PROPELLING AND STEERING SHIPS OR VESSELS, AND OF A NEW OR IMPROVED CONSTRUCTION OF PROPELLER AND FITTINGS OR MECHANISM THEREFOR.
Year: 1879

page_text: PROVISIONAL SPECIFICATION left by John Lorimer Corbett, William
Lochhead, and David Hosie at the Office of the Commissioners of Patents
on the 5th November 1879.
JOHN LORIMER CORBETT, WILLIAM LOCHHEAD, and DAVID HOSIE, all of Glasgow,
in the County of Lanark, North Britain. "IMPROVEMENTS IN PROPELLING AND
STEERING SHIPS OR VESSELS, AND OF A NEW OR IMPROVED CONSTRUCTION OF
PROPELLER AND FITTINGS OR MECHANISM THEREFOR.'
"
This Invention has reference to a new or improved construction of horizontal
feathering propeller and its fittings, for the propulsion and steering of steam ships
or vessels.
This propeller is susceptible of various modifications or combinations of its parts,
and of being fitted in various positions in the lower part of the ship, and which
it is considered will have important advantages over all other horizontal propellers
and screw propellers heretofore tried or used, namely:-More direct and greatly
increased propelling effect; simplicity of featbering gear; prevention of all racing
by complete and deep immersion; great power of steadying and manoeuvering the
ship by the propeller without interfering with the speed or reversing of the steam
engines.
The nature and novelty of this said Invention or improved construction of
propeller consist as follows:-In the simplest modification, the propeller consists of
two propelling feathering blades formed or secured on the outer ends of an
oscillating horizontal radial arm or spindle, which swivels by journals and collars
near its centre in bearings on a large, strong, hollow boss, or eye on the lower end
of its main vertical driving shaft. This vertical shaft may be driven direct, as the
crank shaft of the steam engine or cylinders, which would preferably be ranged
horizontally and radially round it on a bed plate on one of the upper decks, and
having the connecting-rods from each piston coupled direct to a single crank on
the upper part of the shaft, which works preferably down through the centre of a
hollow projecting water-tight pipe, or wide tube with a water-tight joint or stuffing
box in it, or below at the neck of the shaft and boss of the propeller blades, which
thus revolve horizontally below the hull of the ship, either in a recess cut for it in
the keel or on each side of it when desired as with "twin" propellers.
The propelling vanes or blades are placed or fixed at right angles to each other
(or vertically and horizontally in their propelling, turning, or feathering plane), and

page_text: preferably all to one side on the outer ends of their radial spindle opposite each
other, so that when this propeller is fitted with its driving vertical shaft in the
vertical centre line of the keel in the centre of the ship, either towards the stem or
stern as desired, and is propelling the ship a-head, the one blade would be feathered
horizontally behind its spindle while revolving forward on the "starboard" side of
the keel, and the blade on the opposite arm would be in the vertical propelling
position, while revolving aft on the port side of the keel, so as to force the water
aft on that side, and thus by the displacement of the water and reaction on the
shaft and ship, propel the vessel forward, as a horizontal paddle wheel with radial
feathering paddles or blades at right angles to their driving shaft, instead of parallel
to this, as has been usual in feathering paddles whether placed vertically or
horizontally. But when the vertical driving shaft and blades are turned in the
same direction as the sun, for propelling the ship a-head, then the blades would
each feather horizontally on the port side, and propel in a vertical plane or position
while turning back on the "starboard" side, but vice versa, they would be feathered
in the reverse direction for backing or propelling astern, all without reversing or
interfering with the motion of the steam engines or propeller shaft. The angular
position of thus feathering the blades within the circle of their motion determines
the direction of propulsion, and as a consequence, also the steering or manoeuvring
of the ship to "port" or "starboard as desired.
"
Various mechanical motions or arrangements may be adopted for so feathering
the propeller blades as they come round to the proper positions (or the parts of
their revolution found best) for so propelling a-head or a-stern, or steering by
them also to "port" or "starboard" or broadside on, as before stated. One
arrangement of the direct connections of the duplex blades on a single spindle as
stated, consists in forming or fixing on to the central part of the spindle of the
two propelling blades inside its bearings and hollow central boss and tube, a short
crank or lever, having the lower end of a strong connecting rod jointed to it and
carried up to or above the hollow tube, so as to be jointed at its top end to a lever
direct, or other equivalent of the feathering mechanism proper, and which it will be
seen requires to raise or push down this connecting-rod, and the crank below and
spindle of the feathering propelling blades to the extent of a fourth of a revolution
at the proper times each half revolution of the propeller shaft, and maintain the
blades in their feathered and propelling position while passing round the greater
part of their half revolution. A simple construction or arrangement of this
feathering mechanism consists of a ring or hollow disc cam with a stepped cam
surface or groove in it mounted to revolve loose in a stationary ring collar or other
bearing concentric to the vertical shaft, and with the cam groove in the revolving
plane of motion of one end of the said moving upper lever of the connecting rod
which would have a small anti-friction pulley on it, running on or in the stepped
cam surface or groove. The lever is mounted on a fulcrum or joint pin in the
vertical crank shaft, or otherwise, so as to revolve with it and the connecting-rod,
which it would thus move in accordance with the path of the cam groove, which
would be made to glide in a gentle inclined or curvelineal manner from the one
stepped plane to the other of the stepped groove of the cam, which would keep the
lever steady in shifting on the incline, and while passing round the upper and
lower planes or steps of the cam, during nearly half the revolution of the shaft,
while the one blade was propelling, and the other blade was feathering back to its
reversing and propelling position. The turning of this cam half round would thus
reverse the feathering action, by raising the feathering lever, and connecting-rod
connected to it, direct or through another lever to increase its motion and so propel
a-head or a-stern, while a gradual turning of the cam to a fourth of a revolution to
the "port"
or "starboard," would propel or steer the vessel proportionately to
"starboard " or "port" as desired, to the full extent of broadside on. And this
turning of the cam might be effected on deck by a hand spoke steering wheel on a
vertical shaft led down to reducing wheel gear, or a screw and screw wheel or other
equivalent connected or geared to the cam.
"

page_text: When it is desired to work or feather the blades only by a pulling action, the
said feathering levers and connecting-rods could be duplicated on opposite sides of
the vertical shaft, one connecting rod would always be acting in the pulling
direction, thus reducing all chance of breaking down by the one connecting-rod
having all the strain of steering or feathering the blades by both pressing and
drawing alternately. When four such radial feathering blades are desired on the
same propeller this would be obtained by mounting a second horizontal propeller
spindle with two blades on its outer ends the same as the first in bearings in the
same driving boss and vertical shaft, but at right angles to the first, and in a
horizontal plane sufficiently above or below the first as to cross it, and be oscillated
by a lever and connecting rod of its own, to feather its blades by a separate lever
above at right angles to the the first, actuated by the same feathering mechanism
through the same cam or an equivalent cam in a different vertical plane.
Instead of the said ring cam an angled groove ring or boss might be used mounted
and turned in a similar manner to effect the same feathering purpose either with a
ring working in the groove with or without anti-friction rollers connected by ball
joint arms direct to the upper ends of the rods of the cranks on the propeller spindles,
or through upper levers; or ball rollers on the upper ends of the rods might work
into the curved incline groove of the ring or boss before stated. Or by another
arrangement this angle disc ring or boss either with or without a groove might be
mounted to swivel on a spherical joint on the vertical shaft below its driving crank
(instead of the rocking levers and stepped cam) and have the upper ends of the
connecting rods all jointed by ball or other equivalent joints to its under or outer
edge or groove, and have the angular or eccentric cam action given to the disc by a
hollow sleeve with one or more anti-friction rollers in its lower edge working on a
rim or groove ring on the upper plain side of the disc, and when this sleeve was
turned by the steering screw and screw wheel or reducing wheels before stated, it
would tilt the disc ring towards the "bow," "stern," or "port," or
" starboard," to
give the desired feathering and propelling action to the blades through the cranks
on their spindles.
While by another arrangement the bearing bush itself at the lower end of
the driving shaft might have this angular grooved or cam rim formed on it
so as to be turned in a water-tight stuffing box or cup leather fluid pressure
joint by the said steering gear, in this case fitted inside the ship all so as to feather
the spindle and blades otherwise as before stated. By another arrangement this
angled or cam groove disc or boss might be fitted on the extreme lower end of the
driving shaft, or on the part of the keel below it and be swivelled or made to
oscillate by the action of a reciprocating spindle passed up through a hole in the
lower axial end of the driving shaft actuated by a reciprocating cotter and collar
fitted in and on the shaft inside actuated by the screw or wheel steering gear as
before stated to turn or tilt the groove disc to feather the spindles, in this case
mounted below the large arm disc wheel carrying all the feathering blades or
radial paddles. Another arrangement for actuating the tilting lever or the cam or
angled groove ring or disc for feathering the propelling blades but only suitable for
being fitted above or below the extreme axial end of the driving vertical shaft
consists of a steering or revolving wheel with an eccentric ball or socket pin on or
in it, to which is jointed thereto the outer end of an eccentric revolving connecting
rod having the inner end connected by a ball and socket joint to the revolving said
feathering lever or the groove or cam ring so as to tilt it up and down each half
revolution of itself and the vertical shaft carrying it; the throw of the respective
eccentric pins or joints to which the eccentric revolving connecting rod is attached
being made proportional to give the distance or length of rising and falling motion
required to feather the blades.
While the feathering and propelling spindles and blades or paddles have been
described as formed and fitted to swivel radially on the bearings of their large eye
disc or paddle wheel it is to be understood that they might be fitted to lie at an
angle forwards at their outer end or have the axial line of their inner end set

page_text: tangential to a circle with a radius of from a half to the whole length of their
feathering crank so that its ball pin or roller would work more radially and
tangentially to the feathering cam or angled groove boss or ring; and that the
blades or paddles might be curved forwards scoop-wise as the oars of racing boats
and skiffs are. And further that this new or improved horizontal feathering
propeller or wheel with radially swivelling and feathering paddles might also be
fitted to work as a vertical paddle wheel immersed to any depth according as
desired at any part of the ship found most convenient, that is, at the sides or at
or under the fore or aft quarters as well as under or at the sides of the keel
horizontally, as before described. Although only two and four feathering propelling
blades have been described mounted on two spindles crossing each other in different
planes in their driving boss, it will be understood that three, five, or any desired
number of single radial feathering blades and spindles could be so mounted on a
large boss, disc, or open framed wheel, each worked by a feathering crank on its
end near the eye or centre connected by a ball crank pin working direct into the
curved angular groove of a boss or ring as before stated, but in this case mounted
on the outside of the bearing below the keel of the ship, and turned by or through
the same or equivalent feathering and steering wheel gearing on deck; the lower
end of the shaft working in this case out through a stuffing box at the one side
of the keel to turn the angled groove ring by reducing speed wheels, or a screw
and screw wheel, or edge ring or groove surface cam, as has been described, worked
by hand for feathering the propeller and for steering. It will be evident that this
steering mechanism might be worked by motive power, as by a small rotative
engine or gearing from the main engine under the control of the steersman. While
without the cam motion this feathering of the blades is obtained by the direct
action of a water, steam, or air pressure cylinder having its piston rod or connecting-
rod directly connected to a strong lever, or connecting-rod which would move a
sliding groove collar boss on the main vertical propeller shaft having the upper
end of the feathering connecting-rods of the propeller blades jointed to it. And
. the slide or other inlet pressure and exhaust valve of this cylinder night be moved
automatically by a revolving angled or stepped groove cam on the said vertical
shaft (analogous to the stationary one before described) shifted by the steering
gear to admit the pressure fluid on one side of the piston, and end of the cylinder,
while relieving it on the other so as to cause the piston to feather the blades and
maintain them in proper propelling position during the desired parts of their
revolution. A great part of the pressure fluid being only reserved from the one
side of the piston and end of the cylinder to the other at each change to equalize
the pressure only allowing the portion of fluid to escape required to feather the
blades to their maximum extent beyond the mien or half feathering position which
they would assume as stated by equalizing the pressure in both ends of the cylinder
during the change.
Although only one wheel or set of radial propellers has been described as actuated
on one vertical axis, or solid, or hollow shaft, it will be understood that two such
wheels or sets of feathering paddles might be so actuated in the same axial line,
the one set over the other, the lower boss or wheel carrying its radial arms being
secured on the lower end of a central solid shaft; while the upper wheel or set of
propellers would be secured on a hollow shaft revolving on or outside the inner
solid shaft. The upper set of blades would be feathered by a swivelling disc or
cam above it, while the lower set would be actuated by a similar cam mounted at
the extreme lower end of the solid shaft, the construction and fittings being
substantially as described in reference to the other modifications.