WO2001085538A1 - Anti-cavitation tunnel for marine propellers - Google Patents
Anti-cavitation tunnel for marine propellers Download PDFInfo
- Publication number
- WO2001085538A1 WO2001085538A1 PCT/AU2001/000509 AU0100509W WO0185538A1 WO 2001085538 A1 WO2001085538 A1 WO 2001085538A1 AU 0100509 W AU0100509 W AU 0100509W WO 0185538 A1 WO0185538 A1 WO 0185538A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- propellor
- tunnel
- cowling
- trailing edge
- cavitation
- Prior art date
Links
- 238000000034 method Methods 0.000 claims description 12
- 230000007704 transition Effects 0.000 claims description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 12
- 230000000694 effects Effects 0.000 description 6
- 230000001965 increasing effect Effects 0.000 description 6
- 230000002708 enhancing effect Effects 0.000 description 2
- 230000002093 peripheral effect Effects 0.000 description 2
- 238000004023 plastic welding Methods 0.000 description 2
- 230000001141 propulsive effect Effects 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 230000001133 acceleration Effects 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000003467 diminishing effect Effects 0.000 description 1
- 239000003623 enhancer Substances 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 230000036961 partial effect Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 230000002829 reductive effect Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 239000011435 rock Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63H—MARINE PROPULSION OR STEERING
- B63H5/00—Arrangements on vessels of propulsion elements directly acting on water
- B63H5/07—Arrangements on vessels of propulsion elements directly acting on water of propellers
- B63H5/14—Arrangements on vessels of propulsion elements directly acting on water of propellers characterised by being mounted in non-rotating ducts or rings, e.g. adjustable for steering purpose
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B61/00—Adaptations of engines for driving vehicles or for driving propellers; Combinations of engines with gearing
- F02B61/04—Adaptations of engines for driving vehicles or for driving propellers; Combinations of engines with gearing for driving propellers
- F02B61/045—Adaptations of engines for driving vehicles or for driving propellers; Combinations of engines with gearing for driving propellers for marine engines
Definitions
- TITLE "ANTI-CAVITATION TUNNEL FOR MARINE PROPELLERS" FIELD OF THE INVENTION
- Marine engineers and boat builders have devoted considerable energies to establishing principles for creating a range of propeller types for different tasks in vessels.
- various devices have been developed to enhance the efficiency of conversion from propeller rotation to thrust delivered to a vessel.
- US Patent No 5,906,522 to Hooper discloses a thrust enhancer for marine propellers.
- the device includes a peripheral ring with an exhaust ring concentrically supported within the peripheral ring by a series of struts.
- the struts may further support individual blades.
- the aim of the device is to cause the propulsive force of a marine propeller to be channelled more generally towards a single rearward direction. It is a relatively complex piece of equipment.
- An even more complex device is disclosed in US Patent No
- This duct has two coaxial cowlings which are staggered relative to each other. They are also.nozzled to create a venturi effect.
- the invention is particularly directed to increasing the towing efficiency of watercraft at low speeds, particularly at periods of high slip, such as takeoff.
- JP 58-126288A (MITSUI ZOSEN KK); (b) DE 4223570 C1 (SCHINEEKLUTH); and (c) JP 58-16981A (NIPPON KOKUM KK).
- JP 58-126288 A (MITSUI) provides a convergent ring (of aerofoil section) about a propellor with inclined tips to the vanes.
- DE 4223570 C1 (SCHNEEKLUTH) provides a ring "diffuser" (4) about the device shaft forwardly of, and of reduced diameter relative to, the propellor (1)
- JP 58-126288A (NIPPON) provides a convergent ring (2) about the propellor (1 ), the ring (2) having an aerofoil section, where respective aerofoil sections (21 , 22) are separated by a slot.
- the above devices are, in general, directed towards increased efficiency at low speed and vessel takeoff.
- the device could protect the propellor against damage, eg., due to striking the sea/river bed, rocks, reefs, etc.; and/or to protect marine creatures against propellor strikes.
- protective devices are disclosed in (a) EPO 433510 A1 (TABRAT); (b) US 5,176,550 (HOOPER); (c) US 2,983,246 (MANLEY); and (d) WO 93/17907 (TAYLOR).
- the invention lies in an anti-cavitation tunnel for a propeller of a watercraft, said anti-cavitation tunnel comprising: a cowling having a leading edge and a trailing edge; wherein the maximum distance between the leading edge and the trailing edge of the cowling is less than the maximum depth of a vane of the propeller.
- the invention resides in an anti-cavitation tunnel for use with a propeller of a watercraft, said anti-cavitation tunnel comprising: a cowling having a leading edge and a trailing edge; and attachment means for securing the cowling in an operating position in relation to the propeller; wherein the maximum distance between the leading edge and the trailing edge of the cowling is less than the maximum depth of a vane of the propeller.
- the cowling is non-convergent along its length and is of plain (ie., non-aerofoil) section.
- the trailing edge may be planar or describe at least one rearward projection.
- the trailing edge may describe a series of continuous curved rearward projections.
- the projections are in diametrically opposed pairs.
- the trailing edge may describe a continuous sine or wave pattern.
- the attachment means comprises at least one bracket engageable with an outboard motor.
- the operating position is such that the leading edge of the cowling is located in the vicinity of a plane including an anterior surface of the propeller.
- the attachment means may be in the form of integral moulding.
- the attachment means may be plastic welding.
- the leading edge is substantially located at, or rearwardly of, the plane including the anterior surface of the propeller.
- the maximum distance between the leading edge and the trailing edge of the cowling is in the range of to 3 / 4 of the depth of a vane of the propeller. Most preferably, the maximum distance between the leading and trailing edge is % of the depth of a vane of the propeller.
- the lower portion of the cowling encloses approximately one-half to three-quarters of the length of the propellor and an upper portion of the cowling encloses substantially all of the top of the propellor and tapers down to enclose approximately one-half to three- quarters of the propellor.
- the anti-cavitation tunnel may further comprise a fin located in an upper region of the cowling.
- the anti-cavitation tunnel may also comprise a transition zone between the trailing edge and an upper bracket.
- the invention resides in a method of improving the efficiency of a propeller of a watercraft, said method include the step of: installing an anti-cavitation tunnel according to any one of the above described embodiments in an operative position in relation to the propeller.
- the method may further include the step of installing the anti-cavitation tunnel so that a leading edge of the tunnel is substantially in the same plane as an anterior surface of the propeller.
- the invention may reside in a method of improving the efficiency of a propeller of a watercraft, said method including the step of: locating an anti-cavitation tunnel so that it shrouds an anterior portion of the propeller and exposes a rearward portion of the propeller. .
- the shrouded anterior portion is equal to or larger than the exposed rearward portion when calculated on the depth of the propeller.
- the anterior portion is twice as large as the exposed rearward portion when calculated on the depth of a vane of the propeller.
- FIG. 1 is a perspective view of a first embodiment of an anti- cavitation tunnel according to the present invention
- FIG. 2 is a side view of the anti-cavitation tunnel of FIG. 1 attached to an outboard motor;
- FIG. 3 is a perspective view of the anti-cavitation tunnel and outboard motor of FIG. 2;
- FIG. 4 is a schematic side view of the anti-cavitation tunnel of the present invention showing water flow during use
- FIG. 5 is a schematic top view of the anti-cavitation tunnel of FIG. 4 showing water flow during use
- FIG. 6 is a rear view of a second embodiment of the anti- cavitation tunnel
- FIG. 7 is a side view of the anti-cavitation tunnel of FIG. 6 attached to an outboard motor;
- FIG. 8 is a rear view of a third embodiment of the anti- cavitation tunnel.
- FIG. 9 is a side view of the anti-cavitation tunnel attached to an outboard motor;
- FIG. 0 is a rear view of a fourth embodiment of the anti- cavitation tunnel;
- FIGS. 11 and 12 are respective side and top plan views of the anti-cavitation tunnel of FIG. 10 attached to an outboard motor;
- FIG. 13 is a rear view of an adjustable fin which may be used with the anti-cavitation tunnels of FIGS. 1 to 12;
- FIGS. 14 and 15 are respective side and top plan views of the adjustable fin of FIG. 13 attached to an outboard motor.
- DETAILED DESCRIPTION OF THE DRAWINGS Referring to FIG. 1 , there is shown a first embodiment of the anti-cavitation tunnel 11 comprising a substantially circular cowling 12 with a leading edge 13 and trailing edge 14.
- the cowling 11 is non- convergent along its length and is of plain (ie., non-aerofoil) section.
- the cowling 12 has an upper attachment bracket 15 and lower attachment bracket 16.
- the anti-cavitation tunnel 11 also includes a fin 17 located just aft of upper attachment bracket 15 in an upper region of the cowling 12.
- FIG. 2 there is shown the anti-cavitation tunnel 11 affixed to an outboard motor 18 which, in turn, is attached to the stern 19 of a boat 20.
- the anti-cavitation tunnel 11 is attached by a bolt 21 passing through an aperture in lower attachment bracket 16 and through the guide skeg 22.
- the anti-cavitation tunnel 11 is also attached to the cavitation plate 23 of the outboard motor 18 by bolts 24 passing through apertures drilled in the cavitation plate 23 and into upper attachment bracket 15.
- the cowling 12 does not completely cover the propeller 25 in a fore and aft direction.
- the leading edge 13 is located level with or around a plane including the propeller leading edge or anterior surface 26.
- the trailing edge 14, however, is forward of the rearmost points 27 of the propeller vanes 28.
- the attachment means may be any suitable means known to a skilled addressee.
- the cowling 12 may be integrally moulded with the outer casing of the outboard leg.
- plastic welding may be used to attach the cowling.
- a frame may be used to hold the cowling 11 in position relative to the propeller 25.
- the cowling may be formed or continuous with any appropriate surrounding structure, for example, the hull of a vessel with a fixed propeller.
- the propeller vanes 28 are supported by a central hub 29 which, in turn, is engaged with a drive shaft (not shown).
- the maximum distance between the leading edge 13 of the cowling and the trailing edge 14 of the cowling is the distance "a".
- the maximum depth of the propeller vanes 28 is "b" which is a fore and aft measurement of a vane of the propeller.
- the distance "a” must be less than the distance "b” for the anti-cavitation tunnel to work effectively.
- "a” is in the range of VT to 3 / 4 of "b”.
- "a” is in the range of V to % of "b”.
- the radial clearance between the cowling 12 and the blades 28 of the propellor 25 (for an outboard motor in the 10-140HP range) will be in the range of 10-30mm.
- the scalloped trailing edge 14 is shown as a regular sinusoidal curve around the edge.
- the trailing edge 14 may, in fact, have just a single rearward projection rather than multiple projections as shown. Preferably, however, there are at least two rearward projections creating a curved trailing edge and those projections are ideally located to balance the action of the cowling.
- a plurality of projections, as shown, may be used wherein the projections are arranged in diametrically opposed pairs, thereby creating balance in the function of the anti- cavitation tunnel 11.
- a regular curve is shown, it is clear to a skilled addressee that other geometric shapes will be suitable for the function of the anti-cavitation tunnel and any suitable configuration may be adopted including shapes that are angular. It is also clear to a skilled addressee that, in fact, the trailing edge 14 may be an even edge substantially parallel to leading edge 13 giving a ring effect to the cowling 12.
- This view also shows an upward arc 30 of cowling 12 to meet upper attachment bracket 15, thereby forming a transition zone between cowling 12 and bracket 15.
- This feature provides an additional advantage in that it creates lift during water flow through anti-cavitation tunnel 11 which increases the efficiency of thrust delivery by the outboard motor 18 leading to the boat 20 rising onto the plane quicker and more efficiently.
- This action is enhanced by the presence of fin 17 which projects into the water flow through the cowling 12 and further increases the provision of lift to the motor 18 and efficiency of planing of the boat 20.
- FIG. 3 there is shown a perspective view of anti-cavitation tunnel 11 of the invention located on an outboard motor.
- the cowling 12 is attached via bolt 21 and upper bolts 24 to the skeg 22 and cavitation plate 23, respectively.
- the propeller vanes 28 are attached to central hub 29 which, in turn, is attached to a drive shaft (not shown) by retention nut 31.
- Leading edge 13 describes an intake opening 32 through which water enters in use.
- FIG. 4 there is shown a schematic vector diagram for water flow through the anti-cavitation tunnel 11 when viewed from the side.
- water flows in the direction of the intake arrows 33.
- the flow around fin 17 is shown by the arrows at 34 with a resultant lift to the anti-cavitation tunnel 11 and outboard motor.
- Circular, angular lateral propulsion is provided by the flow from arrows at 35, whereas outward rear lower propulsion is provided by arrows as shown at 36.
- FIG. 5 A further flow schematic is seen in top view in FIG. 5. Again, intake arrows are seen at 33. Circular angular lateral propulsion is seen at 35. Outward lower rear propulsion is shown as 36. An improved outward higher rear propulsion is shown at 37 formed by the combined circular angular lateral propulsion and outward rear lower propulsion.
- the invention may use the lateral forces to gain efficiency in a forward motion. By maximising the lateral forces to increase efficiency, the anti- cavitation tunnel is intended to channel the lateral thrust towards the rear of the propeller. This concentrates the lateral forces to the rear of the propeller but also requires a balancing percentage of the propeller to remain partially exposed, as this allows a more effective flow of lateral thrust.
- a pulsing action is created by the wave effect or scalloped shape of the trailing edge 14 of the cowling 12. It is believed this uses the maximum lateral force to create a pulsing effect which improves the lateral propulsion and helps to improve performance. As noted above, however, the cowling may be produced without the wave effect on the trailing edge. A smaller percentage of exposed propeller to a larger frontward percentage enclosed by the cowling is preferred.
- the anti-cavitation tunnel 111 again of non-convergent, plain (ie., non-aerofoil) section, has a leading edges 113 which is inclined at any angle in the range of 5° to 15° to the vertical (taken as a plane perpendicular to the axis of rotation of propellor 125); while the trailing edge 114 is substantially vertical but spaced forwardly of, the rearmost points 127 of the vanes of the propellor 125.
- the cowling 112 is attached to the cavitation plate 125.
- the cowling 112 is attached to the cavitation plate 123 of the guide skeg 122 by four fasteners (not shown) and to the lower end of the skeg 122 by a lower skeg bracket 150.
- the inclined leading edge 113 provides improved acceleration characteristics as the angle of inclination allows efficient intake flow of the water through the tunnel 111 due to the natural tilt position of the boat in the water.
- the angle in conjunction with the tilt position reduces drag or resistance.
- the trailing edge 114 is preferably spaced a distance C forwardly of the rearmost parts of the propellor 1256, where C is preferably % to VT of b, ie., approximately one-quarter to one-half of the lower portion of the propellor 125 is exposed. As shown in FIG.
- the cowling 1 12 is configured to cover all of the top of the propellor 125 and then cascades down to cover one-half to three-quarters of the propellor 125 in the upper half (ie., one-quarter to one-half of the propellor 125 is exposed).
- the cowling 212 of the anti-cavitation tunnel 211 of FIGS. 8 and 9 extends only over the upper portion of the propellor 225, the lower portion being surrounded by a (stainless steel)rod 212a, attached to the skeg by a lower skeg bracket 250.
- the rod 212a protects the propellor 225 against heavy impacts.
- the cowling 212 with its cascading surface area provides improved performance over a propellor without the tunnel 211 , including improved timing ability.
- FIGS. 10 to 12 show a fourth embodiment of the anti- cavitation tunnel 311, which is protected by a cage 370 which totally protects the tunnel 311 (and propellor 325) without diminishing the performance advantages provided by the tunnel 311.
- the performance of the boat, fitted with any one of the anti- cavitation tunnels hereinbefore described, can be further improved by the fitting of an adjustable fin 480, hingedly mounted at the rear of the cavitation plate 423 ' on the skeg 422 and adjustable manually (via a turnbuckle) or mechanically (via a pneumatic or hydraulic ram 481 ).
- the fin 480 co-operates with the tunnel to improve lift generated by the propellor.
- the anti-cavitation tunnel may be manufactured in any suitable material, including stainless steel, aluminium or high density plastic.
- the inventor has found that the anti-cavitation tunnel increases the performance of marine craft, including increasing the thrust and fuel efficiency of the drive system and decreasing cavitation around the propeller (eg., enabling a 70HP motor to provide the same thrust as a standard 90HP motor without the tunnel).
- the invention has also provided increased stability in steering and, due to the channelling of the water, appears to quieten the exhaust note of an outboard motor.
- the top end speed of a boat may also be increased and the vessel will have better turning characteristics when the device is used with an outboard motor.
- Rubber gaskets may be used in the attachment of the invention to a motor to prevent water leakage into bolt holes and also minimise the effects of vibration.
- the cowling of the anti-cavitation tunnel may be formed by a truncated cylinder with a leading edge perpendicular to its longitudinal access and a trailing edge angled to that axis having the widest portion of the cowling at the bottom of the cowling.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- Ocean & Marine Engineering (AREA)
- Structures Of Non-Positive Displacement Pumps (AREA)
- Hydraulic Turbines (AREA)
- Prevention Of Electric Corrosion (AREA)
Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CA002407927A CA2407927A1 (en) | 2000-05-05 | 2001-05-04 | Anti-cavitation tunnel for marine propellers |
AU2001255979A AU2001255979B2 (en) | 2000-05-05 | 2001-05-04 | Anti-cavitation tunnel for marine propellers |
EP01929096A EP1286882A1 (en) | 2000-05-05 | 2001-05-04 | Anti-cavitation tunnel for marine propellers |
AU5597901A AU5597901A (en) | 2000-05-05 | 2001-05-04 | Anti-cavitation tunnel for marine propellers |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AUPQ7331A AUPQ733100A0 (en) | 2000-05-05 | 2000-05-05 | Anti-cavitation tunnel for marine propellers |
AUPQ7331 | 2000-05-05 | ||
AUPQ8255 | 2000-06-20 | ||
AUPQ8255A AUPQ825500A0 (en) | 2000-06-20 | 2000-06-20 | Anti-cavitation tunnel for marine propellers |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2001085538A1 true WO2001085538A1 (en) | 2001-11-15 |
Family
ID=25646323
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/AU2001/000509 WO2001085538A1 (en) | 2000-05-05 | 2001-05-04 | Anti-cavitation tunnel for marine propellers |
Country Status (5)
Country | Link |
---|---|
US (1) | US20030148675A1 (en) |
EP (1) | EP1286882A1 (en) |
CN (1) | CN1440346A (en) |
CA (1) | CA2407927A1 (en) |
WO (1) | WO2001085538A1 (en) |
Families Citing this family (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7958796B2 (en) * | 2008-11-12 | 2011-06-14 | Hiwin Technologies Corp. | Screw-driven fan device |
DE102012201539A1 (en) * | 2012-02-02 | 2013-08-08 | Siemens Aktiengesellschaft | Gaining data about a state of a liquid |
CN104015909B (en) * | 2014-05-29 | 2017-01-11 | 哈尔滨工程大学 | Agitating water jet propeller |
CN104015910B (en) * | 2014-05-29 | 2017-01-04 | 哈尔滨工程大学 | Peculiar to vessel being combined agitates hydraulic propeller |
CN107117277A (en) * | 2017-04-12 | 2017-09-01 | 哈尔滨工程大学 | PODDED PROPULSOR with bionical conduit |
CN107200111B (en) * | 2017-05-22 | 2019-03-05 | 哈尔滨工程大学 | A kind of cooling conduit |
CN107244379B (en) * | 2017-06-30 | 2019-10-15 | 哈尔滨工业大学 | A kind of flow control method inhibiting underwater sailing body and hydrofoil surface cavitation phenomenon |
TW202037535A (en) * | 2019-04-11 | 2020-10-16 | 般若科技股份有限公司 | Propelling system of powered ship including a support frame, an outboard motor, a diversion component, and a water introducing seat |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2983246A (en) * | 1960-08-04 | 1961-05-09 | Manley Audre Marie | Propeller guard for outboard motorboat |
JPS5816981A (en) * | 1981-07-18 | 1983-01-31 | Nippon Kokan Kk <Nkk> | Wring propeller with duct |
JPS58126288A (en) * | 1982-01-19 | 1983-07-27 | Mitsui Eng & Shipbuild Co Ltd | Propeller for ship |
EP0433510A1 (en) * | 1988-07-26 | 1991-06-26 | Paul Emile Camille Talvat | Protection device for outboard motor propellors |
US5176550A (en) * | 1989-09-29 | 1993-01-05 | Hooper Robert P | Engine propeller blade and lower unit protector |
WO1993017907A1 (en) * | 1990-09-21 | 1993-09-16 | Taylor Guy Jr | High performance boat prop guard and bracket |
DE4223570C1 (en) * | 1992-07-17 | 1993-09-16 | Herbert Prof. Dr.-Ing. 5100 Aachen De Schneekluth | Streamline control for variable pitch marine screw - has ring duct with smaller diameter than screw to reduce flow rate around hub and increase flow rate through propeller blades |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4637801A (en) * | 1984-07-12 | 1987-01-20 | William H. Flood | Thrust enhancing propeller duct assembly for water craft |
-
2001
- 2001-05-04 WO PCT/AU2001/000509 patent/WO2001085538A1/en not_active Application Discontinuation
- 2001-05-04 EP EP01929096A patent/EP1286882A1/en active Pending
- 2001-05-04 US US10/258,600 patent/US20030148675A1/en not_active Abandoned
- 2001-05-04 CN CN01812235.3A patent/CN1440346A/en active Pending
- 2001-05-04 CA CA002407927A patent/CA2407927A1/en not_active Abandoned
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2983246A (en) * | 1960-08-04 | 1961-05-09 | Manley Audre Marie | Propeller guard for outboard motorboat |
JPS5816981A (en) * | 1981-07-18 | 1983-01-31 | Nippon Kokan Kk <Nkk> | Wring propeller with duct |
JPS58126288A (en) * | 1982-01-19 | 1983-07-27 | Mitsui Eng & Shipbuild Co Ltd | Propeller for ship |
EP0433510A1 (en) * | 1988-07-26 | 1991-06-26 | Paul Emile Camille Talvat | Protection device for outboard motor propellors |
US5176550A (en) * | 1989-09-29 | 1993-01-05 | Hooper Robert P | Engine propeller blade and lower unit protector |
WO1993017907A1 (en) * | 1990-09-21 | 1993-09-16 | Taylor Guy Jr | High performance boat prop guard and bracket |
DE4223570C1 (en) * | 1992-07-17 | 1993-09-16 | Herbert Prof. Dr.-Ing. 5100 Aachen De Schneekluth | Streamline control for variable pitch marine screw - has ring duct with smaller diameter than screw to reduce flow rate around hub and increase flow rate through propeller blades |
Also Published As
Publication number | Publication date |
---|---|
CA2407927A1 (en) | 2001-11-15 |
EP1286882A1 (en) | 2003-03-05 |
US20030148675A1 (en) | 2003-08-07 |
CN1440346A (en) | 2003-09-03 |
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