Marine propulsion – Jet drive
Reexamination Certificate
1999-12-22
2001-05-29
Avila, Stephen (Department: 3617)
Marine propulsion
Jet drive
C440S046000
Reexamination Certificate
active
06238256
ABSTRACT:
FIELD OF THE INVENTION
This invention generally relates to water jet apparatus for propelling boats and other marine craft. In particular, the invention relates to means for mounting a water jet apparatus to the hull of a boat.
BACKGROUND OF THE INVENTION
It is known to propel a boat or other watercraft using a water jet apparatus mounted to the hull, with the powerhead being placed inside (inboard) the hull. The drive shaft of the water jet apparatus is coupled to the output shaft of the inboard motor. The impeller is mounted on the drive shaft and housed in a jet propulsion pipe or water tunnel.
To facilitate use of water jet-propelled boats in shallow water, it is known to mount the water jet at an elevation such that the water jet does not project below the bottom of the boat hull. This can be accomplished, for example, by installing a duct in the stern of the boat, the duct being arranged to connect one or more inlet holes formed in the bottom of the hull with an outlet hole formed in the transom. The water jet is then installed outside the hull in a position such that the water jet inlet is in flow communication with the duct outlet at the transom. Such a system is shown in Australian Patent Specification No. 262306, published in 1963. Alternatively, the water jet can be installed inside the duct built into the hull, as shown in U.S. Pat. No. 5,181,868.
In another type of design, a water jet apparatus is installed inside the hull and penetrates the transom. An inlet housing of the water jet has a horizontal opening and an inclined water tunnel for guiding water to the impeller. The horizontal opening of the inlet housing is mounted in a hole in the bottom or near the bottom of the hull. A similar design is disclosed in Swiss Patent No. 481788.
In many water jet units powered by inboard engines, the drive shafts and pump mountings (which must penetrate the hull) are placed below the waterline. This mounting system has the disadvantage that various gaskets and seals are required to ensure the integrity of the installation. Leakage at any of the mounting and shafting locations can be disastrous.
There is a need for a boat design which would allow a water jet apparatus to be mounted to a hull with penetrations for the drive shaft and shift and steering control system. The area of these penetrations through the hull should be minimized. In addition, the mounting arrangement should allow for easier installation than is the case with the above-described prior art mountings.
SUMMARY OF THE INVENTION
The present invention is directed to an arrangement for mounting a water jet apparatus to a hull of a boat or other marine craft. In accordance with the preferred embodiment, the hull has a cavity defined by a generally horizontal section, a generally vertical section connected to the horizontal section and a pair of side walls connected with the horizontal and vertical sections. An inlet housing of the water jet apparatus is installed in the cavity. The inlet housing has a bore in which the drive shaft is rotatably supported. The drive shaft is coupled to an output shaft of an inboard motor via an opening in the generally vertical hull section at the front of the cavity.
In the installed state, a top section of the inlet housing abuts an exterior surface of the horizontal hull section and a front section of the inlet housing abuts an exterior surface of the generally vertical hull section. The front section of the inlet housing is attached to the generally vertical hull section by means of a front plate which abuts the interior surface of the latter. The top section of the inlet housing is attached to the horizontal hull section by means of a top mounting plate which abuts an interior surface of the horizontal hull section. One set of fasteners hold the top mounting plate, the horizontal hull section and the top section of the inlet housing together. Another set of fasteners hold the front plate, the generally vertical hull section and the front section of the inlet housing together.
In accordance with the preferred embodiment of the invention, the front plate has an opening which communicates with a first cavity in the front section of the inlet housing via the aforementioned opening in the generally vertical hull section. The front end of the drive shaft resides in this first cavity in the inlet housing. The openings in the front plate and the generally vertical hull section allow the drive shaft to be coupled to the output shaft of the inboard motor. The front face of the front section of the inlet housing has an endless recess disposed along a closed curve which encompasses the first cavity. A seal is placed in this recess to minimize leakage of water through the opening in the generally vertical hull section. The fasteners for attaching the inlet housing to the generally vertical hull section reside within the ambit of the seal.
Further in accordance with the preferred embodiment of the invention, the top mounting plate is penetrated by the shift and steering control system. In particular, the top mounting plate has an opening which communicates with a second cavity in the top section of the inlet housing via an opening in the horizontal hull section. A shift and steering control housing, which rotatably supports the shift and steering shafts, is seated in the second cavity and penetrates the openings in the horizontal hull section and in the top mounting plate. The top face of the top section of the inlet housing has an endless recess located along a closed curve which encompasses the second cavity. A seal is placed in this recess to minimize leakage of water through the opening in the horizontal hull section.
In accordance with a further aspect of the preferred embodiment, the shift and steering cable assemblies, which are respectively connected to shift and steering shafts via upper shift and steering levers, are supported at respective heights above the top mounting plate by respective mounting brackets. These mounting brackets extend upward from and are integrally connected to the top mounting plate.
REFERENCES:
patent: 3109407 (1963-11-01), Dorst
patent: 3572281 (1971-03-01), Becker
patent: 5254024 (1993-10-01), Kobayashi et al.
patent: 5752864 (1998-05-01), Jones et al.
patent: 5967868 (1999-10-01), Ito et al.
patent: 262306 (1963-05-01), None
patent: 481788 (1970-01-01), None
patent: 1321564 (1963-02-01), None
patent: 724662 (1966-11-01), None
Avila Stephen
Bombardier Motor Corporation of America
Flaherty Dennis M.
LandOfFree
Arrangement for mounting propulsion unit to boat hull does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Arrangement for mounting propulsion unit to boat hull, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Arrangement for mounting propulsion unit to boat hull will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2445037