WO2001096177A1

WO2001096177A1 - Unit for protecting a propeller of a boat

Info

Publication number: WO2001096177A1
Application number: PCT/CA2001/000906
Authority: WO
Inventors: Claude Marois
Original assignee: Claude Marois
Priority date: 2000-06-15
Filing date: 2001-06-14
Publication date: 2001-12-20
Also published as: AU2001270379A1; CA2312253A1

Abstract

A unit for protecting a propeller of a boat from underwater hazards like shoals, reefs and algae. The unit comprises a frame (10) which may have a floating structure, a supporting arrangement (14) for holding the propeller (8) below a bottom line of the floating frame, a mounting assembly (16) for pivotally attaching the floating frame (10) behind the boat (6) with a pivot axis (18) transverse to the boat (6), and a protective fin assembly (22) downwardly projecting from the frame (10) in front of and under the propeller (8). The protective fin assembly (22) has a transverse cutting blade (24) extending near the propeller. A spring arrangement (46) can be provided between the boat (6) and the floating frame (10) for exerting a pressure against pivotal motion of the floating frame (10) with respect to the boat (6).

Description

UNIT FOR PROTECTING A PROPELLER OF A BOAT

FIELD OF THE INVENTION

The present invention relates to a unit for protecting a propeller of a boat, and more particularly to a unit pivotally attachable behind a boat and provided with a protective fin assembly' for safe and undamaging practice of boating in shallow waters and even in rapids hiding underwater hazards.

BACKGROUND Boaters and other persons practising boating, like fishermen and hunters, are all susceptible to cross shoals or other navigation hazards like algae one day, which are likely to cause expensive damages to the propeller of the boat, notwithstanding the possible danger to the safety of the boaters in such instances.

Known in the art are US patents 5,470,262 (Bustillo, Sr.), 5,664,977 (Dinkowitz et al . ) , and 5,759,075 (Steep et al.), which show protective devices in the form of an enclosure, a sled and a guard attached to the propeller shaft structure and arranged to surround or guard the propeller. In many cases, protection is limited to algae as a shock caused by. an obstacle would be taken by the propeller shaft structure instead of the propeller, which is not necessarily better.

Also known in the art are US patents 5,322,030 (Brehmer) and 5,350,327 (Self et al.), which show support devices attachable behind a boat for adjusting the height of an outboard motor. The adjustment requires user intervention each time a change of height is desired and the devices are not adapted to protect the propeller in the event of a collision with an underwater obstacle. Also known in the art is US patent 5,238,432 (Renner) , which shows an impact avoidance system having arms attachable behind and under the boat and arranged to lift the motor by a lever effect produced by contact of an underwater obstruction with the arm extending under the boat. The boat underside attachment of the lower arm of the system increases the underwater depth of the boat and the water drag. It must be leak-proof, and provides no protection of the propeller against algae jamming. Also known in the art are US patents 3,877,667 (Monckton) , 4,239,013 (Haynes), 5,205,764 (Thiger) , 5,259,331 (Hagan) , 5,293,832 (Potter, Jr.), 5,667,415 (Arneson) , 5,673,643 (Poppa), and 5,741,165 (Saito et al.), which illustrate the state of the art relating to boat motor equipment .

The protective devices found in some of the above- mentioned patent documents are all unsatisfactory in one or many aspects, for example the safety of the boaters, the reliability and/or manufacturing cost and/or practical applicability of the devices, the compatibility with boat and motor models (e.g. inboard and outboard motors), the real protection level and/or kind of protection provided by the devices, to name only those.

Furthermore, people would most certainly enjoy being capable of riding with their boats in rapids without damaging the propeller, even if just for the thrill.

SUMMARY

An object of the invention is to provide protection to a propeller and related parts against underwater hazards like shoals, reefs and algae in an efficient and convenient manner. Another object of the invention is to propose a unit providing such a protection, which is simple in construction and secure for boating.

Another object of the invention is to provide such a unit which is compatible with a large number of boat models and is usable for inboard and outboard motors.

According to the present invention, there is provided a unit for protecting a propeller of a boat, comprising: a frame; supporting means attached to the frame, for holding the propeller below a bottom line of the frame; mounting means for pivotally attaching the frame behind the boat with a pivot axis transverse to the boat; and a protective fin assembly downwardly projecting from the frame in front of and under the propeller, the protective fin assembly having a transverse cutting blade extending near the propeller.

Preferably, the frame has a floating structure and the transverse cutting blade extends substantially in front of the propeller. According to a preferred embodiment, the unit further comprises spring means mountable between the boat and the frame, for exerting a pressure against pivotal motion of the frame with respect to the boat;

Preferably, the protective fin assembly has an elongated bar having a rearward declining front portion having a front end connected under the floating frame and a rear end extending below a lowermost level of the propeller, and a rear portion projecting rearward from to the rear end of the front bar and extending under the propeller, the cutting blade being attached on the front portion of the elongated bar. Preferably, an additional transverse cutting blade is also provided on the elongated bar for improved cutting action. A detailed description of preferred embodiments will be given herein below with reference to the following drawings, in which like numbers refer to like elements.

BRIEF DESCRIPTION OF THE DRAWINGS

Figures 1, 2 and 3 are side elevation, rear elevation and perspective views of an embodiment of the unit according to the invention, for an outboard motor;

Figures 4 and 5 are side elevation and rear elevation views of another embodiment of the unit according to the invention, for an inboard motor housed in the unit;

Figures 6 and 7 are side elevation and rear elevation views of another embodiment of the unit according to the invention, for an inboard motor housed in the boat; and

Figure 8 is a side elevation view of another embodiment of the unit according to the invention, in particular for a small outboard motor.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to Figures 1, 2 and 3, there is shown an embodiment of the unit 2 according to the invention, particularly adapted for supporting an outboard motor 4 behind a boat 6 and protecting its propeller 8. The unit 2 has a floating frame 10 and a supporting arrangement, e.g. a rear transom wall 14 of the floating frame 10 in the illustrated case, to hold the propeller 8 below a bottom line 12 of the floating frame 10. A mounting assembly 16 is provided to pivotally attach the floating frame 10 behind the boat 6 with a pivot axis 18 transverse to the boat. A spring arrangement 20 ountable between the boat 6 and the floating frame 10, is provided for exerting a stabilizing pressure against pivotal motion of the floating frame 10 with respect to the boat 6. A protective fin assembly 22 downwardly projects from the floating frame 10 in front of and under the propeller 8, thereby protecting it from possible collisions with underwater shoals and reefs. The protective fin assembly 22 has a transverse cutting blade 24 extending substantially in front of the propeller 8 to cut possible algae.

Thus, in use, any shoal or reef colliding with the fin assembly 22 will lift the whole unit 2 with the propeller 8 without any risk of damaging the motor 4 and other related parts as the shock is entirely absorbed by the unit 2 which then pivots about the axis 18. The only part of the boat 6 which may be slightly stressed in the process is its rear transom wall 26 to which is pivotally attached the unit 2. However, rear transom walls are generally built strong to support the motor, so the aforesaid stress should even be negligible .

Any algae in the path of the propeller is likely to be trimmed by the blade 24 as it is pulled by the propeller, preventing its jam.

The protective fin assembly 22 is preferably made of an elongated bar 28 having a rearward declining front portion and a rear portion projecting rearward from a rear end of the front portion and extending under the propeller 8. The front end of the bar 28 can be connected under the floating frame 10 by means of a bracket 30 or any other suitable fastener. The rear end of the front portion preferably extends below a lowermost level of the propeller 8. A strengthening bar 32 preferably extends between the floating frame 10 and the elongated bar 28 at a predetermined distance behind the front end of the elongated bar 28 to provide appropriate support to the bar 28 against shocks from obstacles and preventing it from deflecting upwardly. In the illustrated case, the strengthening bar 32 is affixed to the rear transom wall 14 of the floating frame 10 by means of a bracket 34 and downwardly projects and is fastened to the elongated bar 28 by welding or other suitable fastening way. Other types of strengthening can be implemented if desired, e.g. V-arranged arms (not shown in the Figures) extending between the floating frame 10 and the bar 28.

The cutting blade 24 may be formed of V-arranged deviating wings as best shown in Figure 3, projecting rearward on opposite sides of the front portion of the bar 28 and extending aside to cover an operating diameter of the propeller 8. The front part of the blade 24 can be bevelled and provided with teeth (not shown in the Figures) to improve the cutting of algae or other undesirable submerged bodies. However, a not too cutting edge may be preferred when safety and environment preservation are of concern while still obtaining the desired cutting results to prevent propeller jamming.

An additional transverse cutting blade 36 preferably extending in front of the propeller 8 may do the trick, with the cutting blades 24, 36 being spaced from each other and possibly having different sizes. As best shown in Figures 1 and 2, the bottom 12 of the floating frame 10 preferably matches a stern bottom 38 of the boat 6, for smooth flow of water between the boat 6 and the unit 2. Other shapes can however be used if desired.

The mounting assembly 16 may be formed of a wedge-shaped mounting frame 40 attachable to the rear transom wall 26 of the boat 6 for example by means of bolts and brackets 42 as best shown in Figure 2. The mounting frame 40 preferably forms a projection of the rear transom wall 26 adapted to receive the front hull wall 44 of the floating frame 10 in a hanging flap arrangement. Thus, in ordinary state, the front hull wall 44 stands inside the mounting frame 40 and the bottom 12 of the floating frame 10 is level or almost level with the bottom of the mounting frame 40 and the bottom 38 of the boat 6. When a collision occurs, the floating frame 10 pivotally lifts about the pivot axis 18 and the shape of the mounting frame 40 reduces the amount of water hitting the front hull wall 44 while the spring arrangement 20 urges the floating frame 10 to return back to its ordinary position.

The spring arrangement 20 may conveniently be formed of one or more inflatable balloons 46 coupled between the mounting frame 40 (on the side of the boat 6) and the front hull wall 44 of the floating frame 10 at low positions of it. Other kind of spring elements can be used if desired. A pneumatic system (not shown in the Figures) can be provided to adjust the pressure of the balloon 20 so as to change the normal operating angle of the unit 2 with respect to the boat 6, e.g. in a lifted position for boating in shallow waters.

The bottom, side and top walls of the floating frame 10 may be arranged to form a lower closed compartment 48 and an upper open compartment 50 above the lower closed compartment 48, with the side wall at a rear of the floating frame forming the rear transom wall 14. The floating frame 10 may be made of aluminum or fiberglass or other suitable material if desired.

The elongated bar 28 (and other similar bar pieces of the unit 2) is preferably made in stainless steel, although other material like galvanize steel can be used if desired. Typically, the cross-sectional size of the bar 28 can be half an inch (width) by 2 inches (height) for 20 to 100 hp motors. For larger motors, e.g. 200 hp, the height may be increased to 3 inches. The cutting blades 24, 36 may typically have a thickness around a sixteenth of an inch. Other sizes may be used depending on the material used and the desired strength of the bar 28 and the blades 24, 36.

Referring to Figures 4-5, the floating frame 10 can be arranged to house an inboard motor 52 in an accommodating inner compartment 56. In such configuration, the supporting arrangement may be embodied by a propeller shaft support 54 extending across the strengthening bar 32, supporting a propeller shaft 58 passing through an opening 62 made in the bottom 12 of the floating frame 10 in alignment with the support 54.- The shaft 58 can be coupled to the motor 52 through a gearbox 60. The stern, e.g. the rear wall 14 of the floating frame 10 may be provided with a rudder support 64 directed behind the propeller 8. The rear portion of the elongated bar 28 may be provided with a rudder end receiving support 66 aligned with the rudder support 64 on the stern. The floating frame 10 may be provided with a cover panel 68 extending over the inner compartment 56, and having front and rear facing air vents 70, 72 for air circulation inside the inner compartment .56.

Referring to Figures 6-7, the inboard motor 52 can be located in the boat 6. In such configuration, the mounting arrangement 16 may be formed of a bracket 74 attachable to the rear transom wall 26 of the boat 6 and pivotally receiving the front portion of the floating frame 10, which may have a bevelled shape. The spring arrangement 20 may, in this case, be made of a middle plate 76 attachable to the rear transom wall 26 of the boat 6 above the bracket 74 to extend over the floating frame 10, and a pair of inflatable balloons 78, 80 projecting under and over the middle plate 76 and urging the floating frame 10 in level position with the boat 6. The balloon 80 projecting over the middle plate 76 is restrained by an arm 82 pivotally attached to the floating frame 10.

The front hull wall 44 of the floating frame 10 may have a bottom central recess 84 for accommodating a universal joint 86 coupling the propeller shaft to the inboard motor shaft 88. A propeller shaft passageway 90 is aligned with the propeller shaft support 54 and extends between the recess 84 and the underside 12 of the floating frame 10. Since the floating frame 10 does not bear the motor 52, it can have a reduced size in comparison with the other embodiments. A rear spoiler 92 can be installed on the floating frame 10 if desired.

The bracket 74 preferably extends at or close to a floating line level of the floating frame 10. The bottom 12 of the floating frame 10 may have a rear portion and an upraised front portion with respect to the rear portion for improved water flow behind the boat 6.

Referring to Figure 8, there is shown an embodiment of the unit according to the invention, particularly adapted for a small outboard motor 4. The frame is made in that case of a linkage fork 94 having a front end provided with the mounting assembly 16. The supporting arrangement is made of a transom structure 96 pivotally connected to the rear end of the linkage fork 94 and having an upwardly projecting outboard accommodating rear transom wall 14 and a downwardly projecting abutment fork 98 for abutment against the rear transom wall 26 of the boat 6 below the mounting assembly 6. The protective fin assembly 22 has an upper end adjustably fastened to the front end of the linkage fork 94 and an intermediary portion 100 adjustably fastened to the abutment fork 98 of the supporting arrangement. The adjustments can be achieved by selecting which ones of mounting holes 102, 104, 106 in the protective fin assembly 22 and the abutment fork 98 are used to fasten the parts together, for example by means of bolts (not shown in the Figure) .

The frame may be provided with a floating body 10 having a front portion detachably fastened with the abutment fork 98 of the supporting arrangement 96 and the intermediary portion 100 of the protective fin assembly 22, and an upper face provided with a bracket 108 detachably fastened to the abutment fork 98 of the supporting arrangement 96 at a distance from the protective fin assembly 22. In this embodiment, the transverse cutting blade 24 preferably extends under the propeller 8, although it may be positioned elsewhere as long as it helps preventing algae from jamming the propeller 8. Additional cutting blades (not shown in the Figure) may be fastened to the bar 28 in front of the propeller 8 if desired.

While embodiments of this invention have been illustrated in the accompanying drawings and described above, it will be evident to those skilled in the art that changes and modifications may be made therein without departing from the essence of this invention. All such modifications or variations are believed to be within the scope of the invention as defined by the claims appended hereto.

Claims

CLAIMS :

1. A unit for protecting a propeller of a boat, comprising: a frame; supporting means attached to the frame, for holding the propeller below a bottom line of the frame; mounting means for pivotally attaching the frame behind the boat with a pivot axis transverse to the boat; and a protective fin assembly downwardly projecting from the frame in front of and under the propeller, the protective fin assembly having a transverse cutting blade extending near the propeller.

2. The unit according to claim 1, wherein: the frame has a floating structure; and the transverse cutting blade extends substantially in front of the propeller.

3. The unit according to claim 2, further comprising: spring means mountable between the boat and the frame, for exerting a pressure against pivotal motion of the frame with respect to the boat;

4. The unit according to claim 3, wherein the protective fin assembly comprises an elongated bar having a rearward declining front portion having a front end connected under the frame and a rear end extending below a lowermost level of the propeller, and a rear portion projecting rearward from the rear end of the front portion and extending under the propeller.

5. The unit according to claim 4, wherein the cutting blade comprises V-arranged deviating wings projecting rearward on opposite sides of the front portion of the bar and extending aside to cover an operating diameter of the propeller.

6. The unit according to claim 5, wherein the protective fin assembly has an additional transverse cutting blade extending substantially in front of the propeller, the cutting blades being spaced from each other and having different sizes.

7. The unit according to claim 4, wherein the protective fin assembly comprises a strengthening bar extending between the frame and the elongated bar at a predetermined distance behind the front end of the elongated bar.

8. The unit according to claim 7, wherein the supporting means comprises a propeller shaft support extending across the strengthening bar.

9. The unit according to claim 8, wherein the frame comprises an inboard motor accommodating inner compartment, a bottom having a propeller shaft opening aligned onto the propeller shaft support, and a stern provided with a rudder support directed behind the propeller.

10. The unit according to claim 9, wherein the rear portion of the elongated bar has a rudder end receiving support aligned with the rudder support on the stern.

11. The unit according to claim 9, wherein the frame has a cover panel extending over the inner compartment, the cover panel being provided with front and rear facing air vents.

12. The unit according to claim 3, wherein the frame has a bottom substantially matching a stern bottom of the boat.

13. The unit according to claim 3, wherein: the frame has a front hull wall; the mounting means comprises a wedge-shaped mounting box attachable to a rear transom wall of the boat and forming a projection thereof receiving the front hull wall of the frame in a hanging flap arrangement; and the spring means comprises an inflatable balloon coupled between the mounting box and the front hull wall of the frame at low positions thereof.

14. The unit according to claim 3, wherein the frame has an outboard motor accommodating rear transom wall extending above the protective fin assembly.

15. The unit according to claim 12, wherein the frame has bottom, side and top walls forming a lower closed compartment and an upper open compartment above the lower closed compartment, the side wall at a rear of the frame forming the rear transom wall.

16. The unit according to claim 7, wherein: the frame has a front portion; the mounting means comprises a bracket attachable to a rear transom wall of the boat and pivotally receiving the front portion of the frame; and the spring means comprises a middle plate attachable to the rear transom wall of the boat above the bracket to extend over the frame, a first balloon projecting under the middle plate and pushing against the frame, and a second balloon projecting over the middle plate and being restrained by an arm pivotally attached to the frame.

17. The unit according to claim 16, wherein: the supporting means comprises a propeller shaft support extending across the strengthening bar; and the frame has a front hull wall having a bottom central recess, and a propeller shaft passageway aligned with the propeller shaft support and extending between the recess and an underside of the frame.

18. The unit according to claim 15, wherein the frame has a rear spoiler.

19. The unit according to claim 17, wherein the bracket extends substantially at a floating line level of the frame, and the frame has a bottom having a rear portion and an upraised front portion with respect to the rear portion.

20. The unit according to claim 2, wherein: the frame comprises a linkage fork having a front end provided with the mounting means, and a rear end; the supporting means comprises a transom structure pivotally connected to the rear end of the linkage fork and having an upwardly projecting outboard accommodating rear transom wall and a downwardly projecting abutment fork for abutment against a rear transom wall of the boat below the mounting means; and the protective fin assembly has an upper end adjustably fastened to the front end of the linkage fork and an intermediary portion adjustably fastened to the abutment fork of the supporting means.

21. The unit according to claim 20, wherein the frame comprises a floating body having a front portion detachably fastened with the abutment fork of the supporting means and the intermediary portion of the protective fin assembly, and an upper face provided with a bracket detachably fastened to the abutment fork of the supporting means at a distance from the protective fin assembly.

22. The unit according to claim 21, wherein the transverse cutting blade extends substantially under the propeller .