US3745964A - Racing lower unit - Google Patents

Racing lower unit Download PDF

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Publication number
US3745964A
US3745964A US00173065A US3745964DA US3745964A US 3745964 A US3745964 A US 3745964A US 00173065 A US00173065 A US 00173065A US 3745964D A US3745964D A US 3745964DA US 3745964 A US3745964 A US 3745964A
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United States
Prior art keywords
lower unit
propeller
shaft
marine propulsion
propulsion device
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00173065A
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English (en)
Inventor
D Henrich
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Outboard Marine Corp
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Outboard Marine Corp
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Filing date
Publication date
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Publication of US3745964A publication Critical patent/US3745964A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H20/00—Outboard propulsion units, e.g. outboard motors or Z-drives; Arrangements thereof on vessels
    • B63H20/24—Arrangements, apparatus and methods for handling exhaust gas in outboard drives, e.g. exhaust gas outlets
    • B63H20/245—Exhaust gas outlets

Definitions

  • ABSTRACT I [52] US. 115/34 R, 115/17, 115/.5 [51] Int. B63h 19/06 Dlsclosed harem a manna PTOIPUISIO devce 5/34, 35 17, 18, prising a lower unit including exhaust gas discharge means located in the lower unit for discharging gas, during forward travel, into the area in front of the [58] Field of Search upper half of the path of the blades of a propeller rotatably carried by the lower unit.
  • the invention relates generally to marine propulsion devices. More particularly, the invention relates to marine propulsion lower units which drive racing propellers and which are adapted for racing. Still more particularly, the invention relates to arrangements for discharging exhaust gases from marine propulsion lower units.
  • Racing propellers are commonly designed to operate at least partially out of the water so as to facilitate operation at relatively high rotational speeds and so as to provide lift to the stern of the supporting boat hull.
  • a relatively slow speed as for instance, during starting or turning
  • Such submergence tends to disadvantageously reduce the rotational speed of the propeller.
  • Such reduction in rotational speed is believed to occur when the propeller is more or less fully submerged because the propeller is then rotating in more or less solid water.
  • the invention is directed to reducing the solidity of the water in the area above the propeller shaft or in the upper half of the path of the propeller blades by introducing from the lower unit, a gas, such as air or exhaust gas into the area in the front of the top half of the path of the propeller blades.
  • the invention provides a marine propulsion lower unit including means operating during forward travel for discharging exhaust or other gas from the lower unit forwardly of the propeller blades and into the area above the propeller shaft and adjacent to the top half of the path of the propeller blades.
  • exhaust gases or air can be introduced.
  • exhaust gas is discharged through a series of vertically spaced ports located in a transversely flat aft margin of the lower unit above the propeller shaft and below the cavitation plate.
  • the gases exiting from the ports are discharged to the atmosphere.
  • the gas discharged through the ports reduces the solidity" of the water and permits faster propeller rotation.
  • One of the principal objects of the invention is the provision of a racing marine propulsion lower unit including means for discharging gases forwardly of the upper half of the path of the propeller blades so that, when the propeller is more or less fully submerged, the
  • a racing lower unit which is capable of providing superior forward thrust for a given engine output and therefor capable of driving a boat at a faster speed for a given engine operating condition.
  • Another of the principal objects of the invention is the provision of a racing lower unit arrangement which provides more effective forward thrust and which can be readily obtained by modifying a conventional lower unit.
  • FIG. 1 is a perspective view, partially broken away and in section, of a marine propulsion lower unit including various of the features of the invention.
  • FIG. 2 is a fragmentary view, in section, taken along line 22 of FIG. 1.
  • a marine propulsion lower unit 11 which embodies various of the features of the invention and which can be a part of either an outboard motor or a stern drive unit.
  • the lower unit 11 includes a drive shaft housing portion 13 which, at its lower end, is joined to a gearcase portion 17.
  • a drive shaft 19 which is powered by an engine (not shown) and which extends into the gearcase portion 17 and is connected by suitable gearing 21 with a propeller shaft 23 carrying a racing propeller 27. While various propellers can be employed,'the illustrated propeller 27 includes two blades 29. Single bladed propellers and propellers with more than two blades can also be employed. i
  • the gearcase portion 17 is also formed with a cavitation plate 31 which is located slightly above the top of the path of the propeller blades 29.
  • the gearcase portion 17 is formed with an exhaust gas passage or conduit 33 which communicates with the hollow interior of the drive shaft housing portion or other suitable exhaust gas passageway 37in the drive shaft housing portion 13 and which includes an exhaust gas discharge outlet 39 rearwardly of the path of rotation of the propeller blades 29.
  • the discharge outlet 39 can be either above or below the cavitation plate 31.
  • the lower unit 11 is generally conventionally constructed.
  • the gearcase portion 17 of the lower unit 11 there is provided in the gearcase portion 17 of the lower unit 11 a bore 41 which extends vertically downwardly from the exhaust gas conduit 33 and which communicates with a series of vertically spaced fore and aft bores 43 which terminate in ports 47 located in a transversely flat rearward trailing edge 49.
  • the trailing edge 49 has a width of about 56 inch and there are seven vertically spaced bores 43, each with a diameter of about /32 inch and each communicating with the generally vertical bore 41 which has a diameter of about inch.
  • the disclosed ports 47 of the vertically spaced bores 43 are evenly spaced at distances of about '75 inch from centerline to centerline and thus extended over a vertical range of about 3% inch.
  • the discharge ports 47 are all located below the cavitation plate 31 and above a boss 51 formed on the gearcase portion 17 around the propeller shaft 23. It is believed that at least some of the advantages of the invention can be obtained when using a discharge configuration which is located, at least in part, as high as about 2 inches above the path of the propeller blades 29.
  • a portion of the exhaust gas exits through the discharge outlet 39 rearwardly of the propeller 27 and, when the propeller 27 is operating partially out of the water, another portion of the exhaust gases is discharged through the ports 47 to the atmosphere.
  • a portion of the exhaust gas exits from the ports 47 and serves to desolidify the water in the area of the upper half of the path of the propeller blades 29 and in front of the propeller 27.
  • the transverse flat or edge 49 serves to assists in aspirating exhaust gas out through the discharge ports 47 as the transverse flat 49 produces a trailing void during passage of the lower unit 11 through the water. Introduction of gases into the void also serves to reduce the drag on forward movement of the lower unit through the water.
  • the area behind the flat 49 is also ventilated, when the cavitation plate 31 is above water by travel of atmoshperic air into the void behind the flat 47.
  • a marine propulsion device comprising a lower unit including a propeller shaft, means rotatably supporting said propeller shaft on said lower unit, a transversely flat rearward surface at the rear of said lower unit above said propeller shaft, a propeller mounted on said shaft rearwardly of said flat surface and for com- .mon rotation with said shaft and having at least one propeller blade, and a bore terminating in a port in said flat surface at the rear of said lower unit and communieating with a source of gas to provide for discharge of gas, during forward travel, into the area in front of the upper half of the path of said propeller blade.
  • a marine propulsion device in accordance with claim 1 and including a plurality of said bores in vertically spaced relation.
  • a marine propulsion device including a lower unit including an exhaust gas passage system, a cavitation plate, and a transversely flat rearward surface below said cavitation plate, a propeller shaft, means rotatably supporting said propeller shaft in said lower unit below said surface, a propeller mounted on said shaft rearwardly of said surface and for common rotation with said shaft and having at least one propeller blade and a plurality of vertically spaced bores respectively terminating in ports at said surface and communicating with said exhaust gas passage system.
  • a marine propulsion device comprising a lower unit including a cavitation plate, a propeller shaft, means rotatably supporting said propeller shaft on said lower unit below said cavitation plate, a propeller mounted on said shaft for common rotation therewith and having at least one propeller blade, and a bore extending in said lower unit, communicating with a source of gas and terminating in a port located at the rear of said lower unit in front of said propeller and below said cavitation plate and above said propeller shaft.
  • a marine propulsion device in accordance with claim 6 including a plurality of said bores located in vertically spaced relation between said cavitation plate and said propeller shaft at the rear of said lower unit.
  • a marine propulsion device comprising a lower unit including a propeller shaft, means rotatably supporting said propeller shaft on said lower unit, a propeller'mounted on said shaft for common rotation therewith and having at least one propeller blade, and a plurality of bores extending in said lower unit and communicating with a source of gas and terminating in vertically spaced ports located at the rear of said lower unit and in front of the upper half of the path of said propeller blade.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Ocean & Marine Engineering (AREA)
  • Exhaust Silencers (AREA)
US00173065A 1971-08-19 1971-08-19 Racing lower unit Expired - Lifetime US3745964A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US17306571A 1971-08-19 1971-08-19

Publications (1)

Publication Number Publication Date
US3745964A true US3745964A (en) 1973-07-17

Family

ID=22630383

Family Applications (1)

Application Number Title Priority Date Filing Date
US00173065A Expired - Lifetime US3745964A (en) 1971-08-19 1971-08-19 Racing lower unit

Country Status (3)

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US (1) US3745964A (enrdf_load_stackoverflow)
JP (1) JPS4830294A (enrdf_load_stackoverflow)
CA (1) CA970225A (enrdf_load_stackoverflow)

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4036162A (en) * 1976-05-11 1977-07-19 Outboard Marine Corporation Marine propulsion device having increased reverse thrust
US4048939A (en) * 1976-03-10 1977-09-20 Jones Jr Allen Free-flooding chamber structuremountable on the underside of a watercraft
US4070983A (en) * 1976-12-23 1978-01-31 Randall Hubert E Reversible outboard motor with exhaust gas discharge control
DE3519599A1 (de) * 1984-06-01 1986-01-02 Steyr-Daimler-Puch Ag, Wien Bootsantrieb
EP0221443A1 (en) * 1985-10-25 1987-05-13 Aquamaster Rauma Oy Method and arrangement for decreasing the rotational resistance of a ship's propeller
US4871334A (en) * 1988-08-04 1989-10-03 Brunswick Corporation Marine propulsion device with improved exhaust discharge
US4891025A (en) * 1987-03-27 1990-01-02 Ab Volvo Penta Arrangement in boat propeller installations
US4897061A (en) * 1988-08-04 1990-01-30 Brunswick Corporation Gearcase exhaust vent for a marine propulsion system
US4911665A (en) * 1988-08-04 1990-03-27 Brunswick Corporation Gearcase exhaust relief for a marine propulsion system
EP0375403A1 (en) * 1988-12-22 1990-06-27 Vosper Thornycroft (Uk) Ltd. Apparatus for reducing propeller cavitation erosion
US5036781A (en) * 1987-04-24 1991-08-06 Jaervi Antti K H Method and the means for removing ice from a ship's channel
US5344349A (en) * 1992-05-27 1994-09-06 Brunswick Corporation Surfacing marine drive with contoured skeg
US5800224A (en) * 1995-09-06 1998-09-01 Sanshin Kogyo Kabushiki Kaisha Splash and anti-cavitation plate for marine drive
US5967866A (en) * 1997-12-02 1999-10-19 Brunswick Corporation Texture gearcase for a marine propulsion system
US6010380A (en) * 1999-08-09 2000-01-04 Wollard; Donald L. Marine exhaust vented forward of propeller hub
US6022251A (en) * 1995-09-06 2000-02-08 Sanshin Kogyo Kabushiki Kaisha Water inlet for marine drive
US9932099B1 (en) * 2017-01-25 2018-04-03 Brunswick Corporation Marine drives having exhaust systems that discharge exhaust gas through a gearcase housing
US10995648B1 (en) 2018-03-27 2021-05-04 Brunswick Corporation Marine drives having a muffler for tertiary exhaust outlet
US11008926B1 (en) 2018-09-28 2021-05-18 Brunswick Corporation System and method for controlling exhaust flow from an internal combustion engine

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS538079Y2 (enrdf_load_stackoverflow) * 1973-03-13 1978-03-01
JPS521894A (en) * 1975-06-23 1977-01-08 Kawasaki Heavy Ind Ltd Fluid thruster
JPS6038895U (ja) * 1983-08-25 1985-03-18 吉田　稔 水上走行装置

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1073920A (en) * 1912-10-28 1913-09-23 Milon Val Miller Under-water exhaust.
US1931075A (en) * 1928-04-04 1933-10-17 Johnson Brothers Engineering C Propeller drive for outboard motors
US3350879A (en) * 1964-09-01 1967-11-07 Kiekhaefer Corp Insulated outboard motor housing
US3431882A (en) * 1967-03-26 1969-03-11 Outboard Marine Corp Marine propulsion device

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3434447A (en) * 1968-01-04 1969-03-25 Richard E Christensen Propeller-driven watercraft

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1073920A (en) * 1912-10-28 1913-09-23 Milon Val Miller Under-water exhaust.
US1931075A (en) * 1928-04-04 1933-10-17 Johnson Brothers Engineering C Propeller drive for outboard motors
US3350879A (en) * 1964-09-01 1967-11-07 Kiekhaefer Corp Insulated outboard motor housing
US3431882A (en) * 1967-03-26 1969-03-11 Outboard Marine Corp Marine propulsion device

Cited By (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4048939A (en) * 1976-03-10 1977-09-20 Jones Jr Allen Free-flooding chamber structuremountable on the underside of a watercraft
US4036162A (en) * 1976-05-11 1977-07-19 Outboard Marine Corporation Marine propulsion device having increased reverse thrust
US4070983A (en) * 1976-12-23 1978-01-31 Randall Hubert E Reversible outboard motor with exhaust gas discharge control
DE3519599A1 (de) * 1984-06-01 1986-01-02 Steyr-Daimler-Puch Ag, Wien Bootsantrieb
EP0221443A1 (en) * 1985-10-25 1987-05-13 Aquamaster Rauma Oy Method and arrangement for decreasing the rotational resistance of a ship's propeller
US4891025A (en) * 1987-03-27 1990-01-02 Ab Volvo Penta Arrangement in boat propeller installations
AU615643B2 (en) * 1987-03-27 1991-10-10 Volvo Penta A.B. An arrangement in boat propeller installations
US5036781A (en) * 1987-04-24 1991-08-06 Jaervi Antti K H Method and the means for removing ice from a ship's channel
US4871334A (en) * 1988-08-04 1989-10-03 Brunswick Corporation Marine propulsion device with improved exhaust discharge
US4911665A (en) * 1988-08-04 1990-03-27 Brunswick Corporation Gearcase exhaust relief for a marine propulsion system
US4897061A (en) * 1988-08-04 1990-01-30 Brunswick Corporation Gearcase exhaust vent for a marine propulsion system
US5083950A (en) * 1988-12-22 1992-01-28 Vosper Thornycroft (Uk) Limited Apparatus for reducing cavitation erosion
EP0375403A1 (en) * 1988-12-22 1990-06-27 Vosper Thornycroft (Uk) Ltd. Apparatus for reducing propeller cavitation erosion
US5344349A (en) * 1992-05-27 1994-09-06 Brunswick Corporation Surfacing marine drive with contoured skeg
US6022251A (en) * 1995-09-06 2000-02-08 Sanshin Kogyo Kabushiki Kaisha Water inlet for marine drive
US5800224A (en) * 1995-09-06 1998-09-01 Sanshin Kogyo Kabushiki Kaisha Splash and anti-cavitation plate for marine drive
US5967866A (en) * 1997-12-02 1999-10-19 Brunswick Corporation Texture gearcase for a marine propulsion system
US6010380A (en) * 1999-08-09 2000-01-04 Wollard; Donald L. Marine exhaust vented forward of propeller hub
US9932099B1 (en) * 2017-01-25 2018-04-03 Brunswick Corporation Marine drives having exhaust systems that discharge exhaust gas through a gearcase housing
US10011341B1 (en) * 2017-01-25 2018-07-03 Brunswick Corporation Marine drives having exhaust systems that discharge exhaust gas through a gearcase housing
US10995648B1 (en) 2018-03-27 2021-05-04 Brunswick Corporation Marine drives having a muffler for tertiary exhaust outlet
US11795858B1 (en) 2018-03-27 2023-10-24 Brunswick Corporation Marine drives having a muffler for tertiary exhaust outlet
US11008926B1 (en) 2018-09-28 2021-05-18 Brunswick Corporation System and method for controlling exhaust flow from an internal combustion engine

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Publication number Publication date
CA970225A (en) 1975-07-01
JPS4830294A (enrdf_load_stackoverflow) 1973-04-21

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