Hull shape of personal watercraft

Details Hull shape of personal watercraft Hull shape of personal watercraft

2000-02-04

2001-11-20

Morano, S. Joseph (Department: 3617)

Ships

Hull or hull adjunct employing fluid dynamic forces to...

C114S055500, C114S056100, C114S061330

Reexamination Certificate

active

06318286

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to a hull shape of a personal watercraft which can enhance speed performance and can reduce rolling of the watercraft.
2. Description of the Related Art
FIG. 7
shows an example of a hull shape of a conventional personal watercraft. The personal watercraft has a hull bottom
50
having a substantially V-shaped cross section. The hull bottom
50
is provided with a plurality of longitudinal strips
51
. A rear portion of the hull bottom
50
, which forms a planing face, is a smooth plane in a longitudinal direction.
With the above-mentioned shape of the hull bottom
50
, however, an angle of planing trim might become smaller than an angle of design trim, or rolling might be generate at a specific speed, depending on a balance of weight and center of gravity or a distribution of an inclination angle (dead rise) of the cross section of the hull bottom in the longitudinal direction.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a hull shape of a personal watercraft which can enhance speed performance, and still more, can reduce rolling of the watercraft.
In order to attain the above-mentioned object, the present invention provides a hull shape of a personal watercraft comprising, a hull bottom having a substantially V-shaped cross section; and a bulging face formed on an outside part of a rear portion of said hull bottom, and protruding downward from an outside front face positioned in front of the outside part; wherein said bulging face comprises, a fore part inclined downward in the rearward direction, and a rear part positioned above a virtual face extended rearwardly from the fore part.
According to the above-mentioned structure, when the watercraft planes on a water, a water flow is turned downward by the fore part of the bulging face which is inclined downward in the rearward direction. Consequently, separation of the water flow is caused in the rear part provided above the virtual face rearwardly extended from the fore part so that a negative pressure is correspondingly generated. Thus, an attracting force is generated in the rear part, thereby lifting a stem. Consequently, an angle of planing trim of the watercraft is increased to approximate to an optimal angle of trim so that speed performance can be enhanced. The bulging face protrudes downward on the outside part of the hull bottom. Therefore, the negative pressure generated in this portion acts partly as a roll damping force, thus the rolling of the watercraft can be reduced. Since the area of the bulging face is restricted to the vicinity of a stern end, course stability is not impeded.
According to a preferred embodiment of the present invention, the front face in the vicinity of the bulging face and the rear part of the bulging face have a respective buttock line which is in parallel with a keel line as seen in a side view. The rear part of the bulging face is formed as a continuous plane which is bent from the fore part. Furthermore, the bulging face is formed between the longitudinal strip provided on the hull bottom to extend in longitudinal direction and a chine, i.e. the outer edge of the hull bottom.
These objects as well as order objects, features and advantages of the present invention will become more apparent to those skilled in the art from the following description with reference to the accompanying drawings.


REFERENCES:
patent: 3216389 (1965-11-01), Thorsen
patent: 3363598 (1968-01-01), Mortrude
patent: 4128072 (1978-12-01), Wood, Jr.
patent: 4492176 (1985-01-01), Arima
patent: 4760810 (1988-08-01), Kobayashi
patent: 4903626 (1990-02-01), Haines
patent: 5063868 (1991-11-01), Fink, Jr.
patent: 5170735 (1992-12-01), Kobayashi
patent: 5351642 (1994-10-01), Ackerbloom
patent: 5588388 (1996-12-01), Maruyama et al.
patent: 5983823 (1999-11-01), Allison
patent: 6000357 (1999-12-01), Allison
patent: 51-45892 (1976-04-01), None
patent: 55091480 A (1980-07-01), None
patent: 1-94097 (1989-04-01), None
patent: 7-215266 (1995-08-01), None
patent: 7-329874 (1995-12-01), None

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