Abstract: A turbine 400 has a central duct 410 which accelerates fluid passing through it and a blade configuration which retards the flow of fluid near the tips of the turbine. This structure results in a vortex having a higher fluid pressure behind the tips of the turbine blades 408 and a lower fluid pressure behind the duct. In the present invention, this vortex is enhanced by (1) an increased acceleration of the fluid passing through the duct 410 and a deceleration of the fluid passing through the blades 408; and/or (2) by a fluid redirection device 850 for directing the fluid passing through the duct towards the outer diameter of the turbine.

Abstract: An exhaust system for marine propulsion units passes engine exhaust gas out through lateral holes in the lower unit casing at the level of the propeller shaft that communicate between an exhaust passage in the propeller-shaft-support unit and the ambient water. This venting mechanism discharges gas at the level of the propeller hub when the vessel is moving slowly. The vented gas enables the engine to rapidly increase its RPM s without excessive engine loading. This allows for increased acceleration and less engine damage. The system may include venting gas though the hub and out the aft end of the propeller. The system may be used with outboard engines, inboard/outdrives, and full inboards. When used with full inboards, a valve mechanism may enable diversion of an adjustable fraction of the exhaust gas through the transom. A drain hole may also be provided to drain water from the gas passage when the lower unit is out of the water.

Abstract: A controllable-pitch propeller for a sport-type watercraft has a push rod eccentrically connected to each blade displaceable in a bore of the propeller hub. The push rod is sealed with respect to the end of that bore by a multifold bellows whose radial flange is clamped by a cap of an axial flange of the housing in which the bore is provided.

Abstract: A propeller device includes a shaft rotatably supported in a marine engine, and a hub secured to the shaft and having three or more axially extending keys. A propeller housing includes three or more pairs of lobes for forming keyways and for engaging with the keys of the hub. The keyways include a narrower outer end for preventing the housing from disengaging from the hub. Three or more stops are disposed between the pairs of lobes. A retainer disc includes a number of angularly spaced ears for engaging with the lobes and the stops and for preventing the propeller housing from being disengaged from the propeller shaft.

Abstract: A propeller device is provided with vent apertures and plugs which fit into the vent apertures to be retained in position during use of the propeller device. The vent plugs are provided with openings therethrough so that fluids can flow from a region within a hub of the propeller device to a region proximate the outer cylindrical surface of the hub. The fluids flowing from the internal portion of the hub flow towards regions of low pressure near the propellers. The plugs can be changed to modify the size of the ventilation aperture without having to change the propeller device itself. One embodiment of the plug is provided with a moveable cover that closes the opening progressively in response to increasing rotational speed of the propeller device.

Abstract: A propeller is made up of a propelling unit having a plurality of blades, a driving unit for driving the propelling unit, and a plurality of deformable transmission units located between the propelling unit and the driving unit such that the transmission units are retained in the retaining slots of the propelling unit and the driving unit. The transmission units are tubular in shape and capable of deforming to absorb an impact force exerting on the transmission units in a direction perpendicular to the longitudinal axis of the transmission units, so as to safeguard the structural integrity of the propeller at such time when the propeller in motion is impacted on by a foreign object.

Abstract: A propeller for a marine propulsion system that provides variable length exhaust paths depending upon the speed of the boat and motor. The propeller includes a propeller hub and an exhaust tube positioned within the propeller hub. The exhaust tube extends past the aft end of the propeller hub and defines a first exhaust passageway. A second exhaust passageway is positioned between the propeller hub and the exhaust tube. The second exhaust passageway is shorter than the first exhaust passageway. At low speeds, engine exhaust exits the longer first passageway, while at moderate speeds, engine exhaust exits the shorter second passageway. Therefore, the effective length of the exhaust path varies depending upon the speed of the motor, such that the length of the exhaust path is specifically tuned to several speeds of the motor.

Abstract: An apparatus for tensioning a subsurface float line and the like during doyment of the line and thereafter includes a capstan rotatably mounted and located in a liquid medium, the capstan having a bore extending from one end of the capstan to the other end, the bore including a plurality of pump blades for moving the liquid through the bore when the capstan is rotated, the capstan also including turbine blades located around the circumference of the capstan and adjacent both ends of the capstan, the capstan also including a circular surface interposed between the turbine blades for communicating with the line to be tensioned. The pump and turbine blades do work when the capstan is rotated thereby creating a counter rotational (drag) force that tensions the line during and after deployment.

Abstract: A duct fixed to a vehicle propelled through an ambient fluid medium is innally provided with spaced channel passages from which the fluid medium is ejected under pressure tangentially of local duct surfaces through Coanda affected slots at the trailing edge of the duct from which only the ejection of the fluid medium occurs. The supply of the pressurized fluid medium under selective control is limited to different angular segments of the channel passages in order to modify the flow stream through the duct so as to perform certain functions such as thrust control and steerage control effects enhancing vehicle maneuverability.

Abstract: A shock absorbing drive sleeve (402, FIGS. 28+) mounts a marine drive propeller (12) to a propeller shaft (22) and has an asymmetric spring rate such that the sleeve has a higher spring rate and greater torque bearing capability for the forward boat direction, and a softer spring rate and greater shock absorption for the reverse boat direction, to protect the weaker reverse drive components of the gear train.

Abstract: In a propeller for a boat, a plurality of stationary blades and a plurality of variable blades are alternately disposed around an outer periphery of a propeller boss. Exhaust passages are formed in the propeller boss to axially pass through the propeller boss at location corresponding to the stationary blades. Despite the provision of the variable blade which is variable in diameter or pitch, the exhaust passage can be formed into a large sectional area in the blade boss without being obstructed by a blade shaft for the variable blade.

Abstract: Disclosed is an apparatus for emergency enablement of a boat propeller. The apparatus includes a central mounting plate having an aperture for engagement with one end of the propeller shaft to which the propeller is attached. A drive plate is affixed to the central mounting plate for drive engagement with the propeller. Upon striking an underwater object, bolts connecting the drive and mounting plate will shear to protect the boat's engine from damage. One or more cantilevered members, the proximal ends of which are fixed around the periphery of the central mounting plate, extend from the mounting plate for disposal within longitudinal spaces of the boat propeller.

Abstract: A plurality of blade shafts spline-connected to bosses of a plurality of propeller blades are rotatably carried on a propeller boss parallel to the axis of the boss, the propeller blades being rotated so as to increase the propeller-diameter D according to an increase in the centrifugal force, and all the blade shafts are mutually connected through a synchronizer including cranks integrally continuously provided on the blade shafts and a single common synchronizing ring. With this arrangement, it is possible to always equally control opening angles of all the propeller blades despite any partial conditional change.

Abstract: This invention provides a variable pitch marine propeller which is replaceable onto the drive shaft of a marine engine and which provides an exhaust channel through the propeller. To improve and increase the flow of exhaust gas through the propeller the propeller is provided with a blade shank having a cross-sectional area perpendicular to the direction of exhaust gas flow which is less than the cross-sectional area parallel to such flow in the region of the shank arm attachment. There are also provided, within the interior of the propeller, internal surfaces formed within the blade arm adjacent the shank and defining at least one channel to allow exhaust gases to flow through the arm and counterweight assembly. In addition, the propeller is formed such that the connecting region between the blade arm and the counterweight on each blade has a reduced radial width, smaller than that of the counterweight mass along an axis parallel to the drive shaft axis and parallel to the flow of exhaust gases.

Abstract: A marine propeller (10) has an integral aft skirt portion (30, 74) with a plurality of slots (34, 36, 38, 40, 42, 44) extending forwardly from the trailing end (32, 72) and dividing the skirt portion into a plurality of circumferentially spaced segments (46, 48, 50, 52, 54, 56) separated from each other at the trailing end by respective slots therebetween and integrally joined to each other at the outer hub (14) forwardly of the slots. Aft trailing blade tips (28e) of the propeller blades (24, 26, 28) meet the outer hub at points (60) offset from the slots to prevent engine exhaust in the through hub exhaust passage (22) from seeking the negative pressure backside surfaces (28b) of the propeller blades through the slots.

Abstract: A propulsion system for a marine outboard drive includes a seal between adjacent ends of a pair of counter-rotating propellers. The seal inhibits fluid flow through a joint between the propellers, while minimizing frictional contact between the counter-rotating propellers. In at least one embodiment, the seal contacts only one of the propellers.

Abstract: A propeller for a boat having a plurality of recesses and a plurality of land portions arranged circumferentially alternately around an outer periphery of a propeller boss which is fitted over and connected to a propeller shaft. A boss of each of propeller blades and each of blade shafts disposed parallel to an axis of the propeller boss to rotatably support such propeller blade are accommodated in each of the recesses, and each of the land portions is provided with an exhaust passage extending axially through the land portion to permit an exhaust outlet in a body of a propelling device to be opened at a rear end face of the propeller boss. Thus, it is possible to discharge an exhaust gas from an engine through the inside of the propeller boss into water.

Abstract: A marine drive having a drive sleeve and a drive sleeve adapter between the propeller shaft and the propeller hub where the drive sleeve absorbs the shock of the propeller striking an object by torsionally twisting a forward end of the drive sleeve which is keyed to the propeller hub and where the adapter is keyed to the propeller shaft and the drive sleeve is keyed to the adapter. The combination provides both high load capability and shock protection.

Abstract: A marine propeller using the circulation control principle of blowing tantially over a Coanda surface at the trailing edge of each blade to develop high blade lift (thrust). Each blade has internal chambers and two blowing slots so that blowing is controllable for forward and for reverse thrust without reversing rotational direction of the propeller. This propeller is capable of generating much greater thrust and ship speed at lower RPM and noise levels than conventional propellers.

Abstract: A double propeller arrangement for a marine propulsion unit, for example of the type which includes a so-called stern-drive. Each propeller has a hub consisting of an inner sleeve with splines for attachment to a propeller shaft, an outer sleeve with propeller blades, and an elastic bushing between the sleeves. Particular to the propeller arrangement is that the inner sleeve of respective propeller hubs is provided with an axial passage for the discharge of exhaust gases from an internal combustion engine connected to the propeller drive.

Abstract: The present invention provides an exhaust gas discharge system for a watercraft. The system has a first discharge path, including a first outlet, primarily for use during high speed vessel operation and a second discharge path, including a second outlet, for use during both low and high speed vessel operation. The first outlet is arranged to constantly remain below a water surface level of a body of water within which the watercraft is operated, while the second outlet is arranged to locate above the water level surface during high speed vessel operation and to locate below the body of water, at a level higher than the first outlet, during idle and low speed vessel operation. Additionally, the second discharge path has an exhaust flow sectional area of a size at least as large as the exhaust flow sectional area of the first discharge path. The system is capable of discharging exhaust gases in a smooth, efficient manner, and is comprised of a relatively simple structure.

Abstract: A propeller for use on low power motors, such as two-horsepower or less electric trolling motors, is provided with three or more blades on a hub wherein the hub diameter to the blade length (i.e. the length of the blade from the hub to the outermost tip) is in the ratio of at least 1.250 to 1. The hub diameter to blade length ration is such as to produce a propeller having increased performance and is substantially weedless. The width of each blade at its root is equal to or greater than the blade length and the ratio of the sum of the widths of the blades to the circumference of the hub is approximately 1.2 to 1. The true or actual pitch of the blades is measured at 0.7 the radius of the propeller and produces the best results as far as performance and weedlessness is concerned within the range of 2" to 7". The leading edge of one blade forms a junction with the hub in close proximity to a plane containing both the longitudinal axis of the hub and the junction of the trailing edge of the next adjacent blade.

Abstract: A marine drive (10) has a spool (36) positioned in the lower horizonal bore (28) and supporting a dual propeller shaft assembly (38, 40). An exhaust passage (130) includes a passage (132) in the drive housing (26) communicating with the horizontal bore (28) at the spool (36), and a spool exhaust passage (134) passing exhaust rearwardly through the spool to the propeller through-hub exhaust passages (136, 138), providing through-hub exhaust through dual propellers (12, 14). An oil passage (152) in the housing (26) communicates with the horizontal bore (28) forwardly of the exhaust passage (132) and lubricates the dual propeller shaft assembly.

Abstract: An exhaust-through-the-hub system described herein includes an apparatus for discharge of exhaust gases from a marine outboard motor to the outer perimeter of an attached pump jet. Exhaust gas is ducted downwardly through the central body of the motor and rearwardly into a plenum cavity positioned in the pump jet. At least one hollow stator vane receives the exhaust gas and discharges the exhaust gas through the stator housing at a substantial depth below the water line, thereby resulting in a quieter running engine. The exhaust-through-the-hub system provides forward thrust when the motor is in forward gear and reverse thrust when the motor is in reverse gear.

Abstract: In a marine drive (10), a drive sleeve (50) between the propeller shaft (22) and the propeller hub (34) absorbs shock after the propeller (12) strikes an object by torsionally twisting between a forward end keyed to the propeller hub and a rearward end keyed to the propeller shaft. The drive sleeve is composed of a plastic material providing torsional twisting angular rotation at a first spring rate less than 100 lb. ft. per degree from 0.degree. to 5.degree. rotation, a second higher spring rate beyond 5.degree. rotation, and supporting over 1,000 lb. ft. torque before failure.

Abstract: A shock absorbing hub for a marine propeller assembly includes an inner spindle telescoped onto the splined drive shaft of the engine, an outer sleeve spaced radially outwardly of the spindle, and a molded-in-place core of elastomeric material filling the space between the spindle and the sleeve to transmit torque between the two while cushioning torsional shock. A housing carrying propeller blades is keyed to the outer sleeve and may be removed therefrom for repair or replacement without taking any retaining components off of the drive shaft.

Abstract: A shock absorbing drive sleeve (50) is provided by a molded plastic member directly mounting the propeller hub (14) to the propeller shaft (22). The sleeve has a rearward inner diameter portion (52) engaging the propeller shaft in splined relation, and a forward inner diameter portion (56) spaced radially outwardly of and disengaged from the propeller shaft. The drive sleeve has a rearward outer diameter portion (58), and a forward outer diameter portion (60) engaging the propeller hub. The drive sleeve and the propeller hub are tapered relative to each other such that a forward outer diameter portion (60) of the drive sleeve snugly engages the propeller hub, and a rearward outer diameter portion (58) is spaced slightly radially inwardly of the hub by a small gap (62) and may partially rotate relative to the propeller hub in response to rotation of the propeller shaft drivingly engaging the rearward inner diameter portion.

Abstract: There is provided a self-actuating variable pitch marine propeller which incorporates two or more blades, each independently rotatable, relative to the propeller hub, between a first lower and a second higher pitch. The blades are preferably mechanically linked by coordinating means and are caused to move preferably by a combination of centrifugal force effect resulting from inertial mass means and the hydrodynamic forces acting upon the blade hydrodynamic surface. The rotation of the blades relative to the propeller hub is limited primarily as to speed of rotation by restricted viscous fluid flow damping means operably connected to the blades. In one preferred embodiment, the viscous flow means further acts as an initial restraint against all motion by closing off the viscous flow orifice until a certain minimum propeller rotational speed is achieved.

Abstract: A propeller vane or blade construction wherein cavitation is precluded at the base of the blade where they join the hub on their leading side by introducing a source of pressurized fluid in this area. The fluid may be pressurized either from the dynamic flow through the unit or by the static flow generated by the operation of the unit.

Abstract: A propeller assembly which includes a barrel with replaceable blade assemblies secured within slots formed in the exterior of the barrel. The slots include a first slot section and a second slot section with the first slot section extending radially deeper than the second slot section. The blade assemblies include L-shaped locking members which slide within the slots formed within the barrel. The shorter leg of the locking members are secured within the deeper first slot sections while the longer leg extends longitudinally within the second slot section. The locking member preferably includes a dovetail cross-section member fixing the shorter leg member to the barrel so as to prevent both longitudinal, torsional and radial movement of the blade assemblies. The barrel is preferably formed of an aluminum material or, more precisely, an aluminum alloy having 60% to 95% essentially pure aluminum while the blade assemblies and securement members are formed of stainless steel.

Abstract: A marine propeller including an inner hub to receive a driving connection to the engine and an outer hub is spaced outwardly from the inner hub to provide a passage therebetween for the discharge of exhaust gas from the engine. A plurality of blades extend outwardly from the outer hub. A propeller is die cast from an aluminum alloy and as cast the outer surface hub is cylindrical in configuration. After casting the trailing end of the outer hub is swaged outwardly by a tapered tool to provide an outwardly flared trailing end, which assists gas flow and enhances performance of the engine.

Abstract: A propeller assembly for mounting on the drive shaft of a motorized water vehicle. The propeller consists of a central hub having a hollow body of circular cross-sectional shape through which exhaust gas from the motor can flow. Integrally formed with the hub are a number of arcuate blades. Each blade has a generally fish-shaped axial cross-sectional shape. In particular, from the leading edge of the blade, the cross-sectional shape increases in thickness until reaching a local maximum at a point near the midchord of the blade and thereafter decreases in thickness until reaching a local minimum. The blade thereafter again increases in thickness along concave surfaces until terminating in a concave trailing edge. The trailing edge of the blades are in communication with the exhaust gas flowing through the hub.

Abstract: A controllable pitch propeller, particularly for a boat drive, has a driven rotating hub and adjustable propeller blades positioned thereon. An adjustment device is provided, having an adjustment ring that can move axially and which has adjustment bars attached to it for adjustment of the propeller blades. At least one continuous waste gas channel is positioned in the hub. In order to relieve the hub of external adjustment forces, the adjustment ring is constructed as a cylinder piston which is movably axially positioned in a cylinder chamber of the hub, and which can be acted upon hydraulically on both sides.

Abstract: Disclosed herein is a marine propulsion device comprising a lower unit including a gear case, a propeller shaft extending in the gear case, an annulus of greater dimension than the propeller shaft and of material weight, and a ring of elastomeric material resiliently connecting the annulus to the propeller shaft is co-axial relation thereto so as to provide for rotation of the annulus in common with rotation of the propeller shaft.

Abstract: A marine propulsion device comprising a propulsion unit including a gearcase having a cylindrical inner surface centered on an axis, a propeller shaft which is located inside the inner surface, which is supported by the gearcase for rotation about the axis, and which has a rearward end adapted to have mounted thereon a propeller, and an annular oil seal extending between the propeller shaft and the inner surface, and a mechanism for protecting the oil seal from foreign matter, the mechanism including an annular member fixed on the propeller shaft, located between the oil seal and the rearward end of the propeller shaft, and spaced from the oil seal, the member having a generally circular outer surface spaced closely adjacent the inner surface and having a beveled surface portion facing the rearward end of the propeller shaft.

Abstract: Each blade includes at its root a root portion that slides axially into a re-entrant cavity that extends axially in the hub. End caps prevent axial removal of the blade roots from the hub. Thus, it is possible to replace an individual damaged blade, and the hubs are interchangeable from ship to ship, although the blades may vary slightly. All of the parts are injection molded of a high-strength fiber-reinforced plastic. The entire assembly can be produced at approximately half the cost of conventional metal propellers. The propeller is intended for use with engines developing 90-250 HP, and the diameter of the propeller is 16-18 inches. The various parts includes apertures and passages so as not to interfere with the discharge of exhaust gases.

Abstract: Vessel provided with at least one water jet propulsion unit consisting of a casing containing, between an intake (3) tangential to the hull (2) and a rear water outlet (4), a duct (5) upstream of the propulsion device, an impeller (6), fixed flow-correction guide vanes (7) and a tail cone (8) carried by the blades which with the casing (9) form the tail pipe (10). The cross section of the tail pipe (10) varies but within narrow limits between the vanes (7) and the outlet (4) by virtue of a number of gas injection slots situated in the area of the trailing edges of the vanes (7) and connected by a circuit to a supply of compressed gas (16). The gas supply circuit includes an external annular chamber (14) formed within the casing and the shroud surrounding the vanes (7) and connected to the injection slots (25, 26, 29). Of application to vessels requiring very high thrusts.

Abstract: Discussed herein is an arrangement for reducing migration of weeds into an area between the gearcase and the propeller hub of a marine propulsion device. The arrangement is intended to reduce the problem of weed migration when a small hub propeller is used.

Abstract: A marine propeller possessing several features; e.g., one-piece cast or molded construction which in one embodiment preferably of the invention is a plastic of the class including polyester; an improved center or core structure in the form of a nave or barrel having an annular wall concentrically surrounding a power-shaft-receiving hub joined to the annular wall by relatively thin spokes configured as vanes functioning as an interior turbine. Propeller blades are joined to and project radially from the exterior of the nave in typical fashion.

Abstract: A marine propulsion device (1) includes a drive housing (6) to which is attached a suitable engine (4), the exhaust of which is pumped downwardly through a suitable passage (20) in the drive housing to adjacent a torpedo housing (7) carrying at least one propeller (9,10). A generally horizontal antiventilation plate (8) is disposed above the torpedo housing, and a strut (22) extends between the plate and the torpedo housing, just forwardly of the upper portion of the propeller. Substantially all of the engine exhaust is forced by the engine from the drive housing passage for discharge into the path of the upper portion of the propeller. In one embodiment, substantially all of the exhaust passes through the strut and is discharged rearwardly therefrom into ventilating engagement with the forward face of the propeller. In another embodiment, a portion of the exhaust (31) is also discharged downwardly through the antiventilation plate onto the upper edge portion of the propeller.

Abstract: Disclosed is a marine propeller for inboard, outboard, or inboard/outboard motors. The propeller is made from a non-metallic composite material that will not deform or deflect even at very high horsepower or RPMs. At the same time, the propeller is substantially less expensive than traditional metallic propellers. An especially unique feature of the propeller is that, unlike metallic propellers, it will shatter when it strikes a solid object in the water, thereby avoiding the engine and drive line damage that occurs when rigid metallic propellers strike a solid object. Also disclosed is a coupling member that permits the propeller to be adapted for use with most inboard/outboard motor configurations.

Abstract: A device for increasing the efficiency of operation of an internal combustion engine used in outboard and inboard/outboard motors comprised of a generally cylindrical member having inner and outer peripheral shell members defining a cylindrical annular space therebetween, wherein are located a plurality of turbine vanes spanning the annular volume between said inner and outer shell members. Said inner and outer shell members and said plurality of vanes are drivingly connected to the propeller shaft of an outboard motor and are mounted coaxially with said propeller shaft. The device is located in the forward end of the inner propeller hub and rotatably mounted in association with the lower unit of said outboard or inboard/outboard motor so that exhaust gases flowing through said lower unit pass through said annular volume. Upon rotation of said propeller shaft, said plurality of vanes are caused to rotate at the same angular velocity thereof.

Abstract: A screw propeller (10) for boats includes two counter-rotating screws (12, 16) coaxial with an annular nozzle (20). The aft screw (16) has a smaller diameter than the forward screw (12) and the nozzle (20) has an annular duct (B) situated upstream of the rear screw (16) and arranged to discharge the exhaust gases from the engine.

Abstract: A hub assembly comprising a driver telescoped within a driven member is disclosed. A plurality of elastomeric members are disposed between the driving and driven members within mating parallel semi-circular grooves in the opposed surfaces of the driving and driven members of the hub.

Abstract: Aeration holes defined by an outer propeller hub include closure devices which seal the aeration holes during rotation of the propeller due to centrifugal forces in a predetermined speed of rotation range. The aeration holes provide high power at low boat speeds and are sealed at high boat speeds to avoid further aeration and loss of forward thrust. The speed of rotation at which the aeration hole are sealed is adjustable.

Abstract: This disclosure relates to a marine propulsion system including a double propeller. To obtain a forward thrust, the two propellers are driven in opposite directions while producing forward propulsion forces. To obtain a rearward thrust, only one propeller is driven in the direction to produce a rearward force. The two propellers are attached to coaxial inner and outer horizontal shafts. A single vertical shaft is coupled by bevel gears to the shafts, and movable clutches couple the driving force to the horizontal shafts.

Abstract: A marine propulsion device including a propeller shaft, a lower unit rotatably supporting the propeller shaft and including a lower unit exhaust passageway, and a propeller adapted to be submerged in water and including an inner hub connected to the propeller shaft. The propeller also includes an outer hub connected to and spaced from the inner hub and defining a propeller exhaust passageway having an inlet in communication with the lower unit exhaust passageway, a plurality of blades extending from the outer hub rearwardly of the inlet, an opening for communicating the lower unit exhaust passageway with water outside of the outer hub, and a member located adjacent and rearward of the opening, and extending forwardly and radially outwardly with respect to the propeller shaft.

Abstract: Improved screw propellers especially useful in the propulsion of small boats are constructed at low cost from cast iron characterized by rounded graphite in a ferritic, pearlitic and/or acicular matrix. The propeller is exceptionally strong and may be driven by a prime mover at a speed up to 9,000 revolutions per minute without the blades losing their pitch or being easily damaged when submerged objects are struck at high speed. The disclosure is also concerned with outboard motors provided with the ductile iron propeller of the invention, and with small power boats having a propulsion unit which includes the ductile iron propeller of the invention. The propeller has certain preferred dimensions and characteristics, and should be constructed from ductile iron having the composition disclosed herein. The disclosed ductile iron propeller improves the operation of propulsion units of the type normally provided with inexpensive light weight propellers for the reasons noted herein.

Abstract: A controllable pitch propeller assembly has an inner housing attached to a main drive shaft, the housing having rails on the outer surface thereof. Modules carrying the propeller blades are positively mounted on the rails, each module having a housing receiving a hub cylinder and bushings axially aligned at opposite sides thereof. Each pair of bushings receives an adjusting piston having an adjusting pin which engages a groove forming a control path in a propeller hub. Each blade is adjusted by a control lever which adjusts each adjusting piston through a mechanical linkage including an adjusting sleeve and a thrust bearing and flange. The hub is provided with open spaces formed between the inner and outer housings to create hub through exhaust ducts.

Abstract: An apparatus for a ship's propeller, whose fins, which may be pitch-controlled, are provided in the vicinity of the leading edges with air openings. These air openings are fed via air ducts in each propeller fin by a compressed air source located in the ship. The compressed air is fed from the ship's compressor to the propeller by an air coupling which is protected by a split covering sleeve. The coupling is fed by an air feed line laid outside the ship's hull along the stern post or propeller strut. The air feed line penetrates the covering sleeve between the propeller strut and the propeller. The air line is connected to a two-piece inlet feed fitting. Air is fed from the inlet fitting through a two-piece bypass ring which rotates with the propeller shaft, to a two-piece air discharge fitting connected to the propeller hub.