GB2036651A - Outboard-engined boats - Google Patents

Abstract

Outboard-engined boats have one or more wheels located at either side of the propeller and extending below it so that the wheels act to support the outboard engine and the rear of the boat and stop the propeller from coming into contact with the bottom when the motor is in its driving position. The wheels are sufficiently strong and of appropriate dimension to enable them to act as the two rear wheels of a three wheel under-carriage for supporting the boat. A nose wheel is preferably provided to constitute the third wheel. <IMAGE>

Description

SPECIFICATION Outboard-engined boats This invention relates to outboard-engined boats.

Many small size motor boats are driven by means of one or more outboard engines mounted at the rear. The engine is usually mounted on a transom extending across the stern of the boat. The outboard engine consists of an internal combustion engine located a short distance above the water-line, a vertical drive shaft in a suitable housing and a propeller connected to the drive shaft and arranged to lie below the water-line and below the level of the bottom of the boat at its stern, in order that the propeller functions in clear water.

Clearly an exposed propeller on the lower end of a drive shaft and housing is very vulnerable to damage and it is conventional to extend the drive shaft housing so that it extends to below the propeller and then as a rearwardly directed base portion called a skeg. The propeller is normally connected to the drive shaft by means of a so-called shear pin connection, so that if the propeller does become slowed down, e.g. by impact with the bottom or by becoming tangled in a piece of rope or vegetation, the shear pin shears and no substantial damage results.

However, once the shear pin has sheared, it is necessary to disassemble parts of the outboard engine, and replace the shear pin which is time consuming.

In order to facilitate landing and to preserve the propeller from damage, it is also customary to mount the outboard engine so that it may be swivelled about a generally horizontal axis which is transverse to the longitudinal axis of the boat, so as to enable the propeller and skeg to be lifted clear of the water or at least to a level above the bottom of the boat at its rear end. Such swivelling mechanisms are prone to malfunction leading to damage to propeller and/or skeg.

Particularly when a boat driven by an outboard engine approaches land, e.g. a beach, there is a risk of damage to the propeller or at least of a sheared shear pin since the skeg does not usually have sufficient strength or an appropriate shape to keep the propeller from touching the bottom. Rather the skeg tends to dig into a sloping beach or the like allowing the propeller to come in contact with the beach.

In order to facilitate landing and handling small outboard-engined boats, particularly inflatables, it is known to fit wheels to a rear transom, the wheels being movable from a raised position in which they do not interfere with the boat's performance to a lowered position in which they act to hold up the stern of the boat and allow it to be pulled along by one or more persons on the ground adjacent the bow, who lift the bow and pull forwards. Such an arrangement is disclosed in French Patent Specification No. 2351856.

I have now discovered that if such wheels are made low enough to be, in the lowered position, lower than the base ofthe outboard motor also when in its lowered position, and made sufficiently strong, landing or beaching under power is possible without damage to the outboard motor.

According to the present invention there is provided a boat having a rear transom, an outboard engine attached to the transom and projecting, in a lowered position, below the-stern of the boat, and, located on each side of the outboard engine at least one wheel movable from a lower position in which the wheel extends lower than the lowermost part of the outboard engine to a raised position in which the wheel does not adversely affect the performance of the boat.

Preferably a pair of wheels are located each side of the outboard engine.

Preferably each wheel or pair of wheels is mounted on a strut which is essentially vertical when the wheels are lowered, and which can be swung about a horizontal axis transverse to the longitudinal axis of the boat and adjacent the upper end of the strut, to raisethewheel or wheel pair to its raised position. Any suitable mechanical means may be used to effect such movement. A suitable locking device may be provided to hold the wheels securely in their lower position when launching or landing the boat. Preferably, the wheel or wheel pair when raised can be secured in a position vertically above the lowered position of the wheel or wheel pair.

Preferably the wheels are lightweight wheels, for example, wheels having plastics e.g. nylon or polypropylene hubs with synthetic rubber e.g. neoprene tyres.

When a boat is fitted with an outboard engine according to the present invention, the risk to damage to the propeller or of a sheared shear pin. is much diminished since the wheels keep the propeller out of harm's way. In addition, the wheels act to support the outboard engine and the weight of the rear end of the boat and accordingly the landing (and the launching) of the boat is very considerably facilitated, not only in terms of speed but in terms of the effort required.

In order yet further to ease landing, a boat having an outboard engine according to the present invention may also have a nose wheel so that the boat is effectively capable of being moved on an undercarriage formed by the nose wheel and the wheels at the stern of the boat. Such a nose wheel may be permanently fitted or removable, and may be of a castor type or may be a double-conical roller such as used on boat trailers to support the keel. Alternatively, it may simply be a ball set r.ollably in a suitable socket with part of its circumference projecting.

Landing boats with outboard engines according to the present invention is accordingly extremely simple since the boat is merely directed towards the shore or a concrete ramp and allowed to run up it until the cavitation plate is out of the water. At this point the person controlling the boat can cut the engine off and step out onto dry land. Difficulties associated with finally judging when to cut out the engine and tilt it up are entirely eliminated.

The invention is illustrated by way of example with reference to the accompanying drawings in which: Figure 1 shows schematically a boat in accordance with the invention from the stern with its wheels raised, Figure 2 shows schematically a boat in accordance with the invention from the stern with its wheels lowered, Figure 3 shows in detail the fixings to one side of the stern of a boat in accordance with the invention, and Figure 4 shows a section through the stern to one side of a boat in accordance with the invention.

Referring to the drawings, the stern of the boat has a transom 11 on which are mounted an outboard engine and housing 12, having a vertical drive shaft housing 13, a propeller 14 and cavitation plate 15.

The engine and housing 12 is mounted so that it can be rotated by means of a handle (not shown) around the vertical drive shaft axis. The mounting may also be such that the propeller 14 may be raised to a level higher than that of the bottom 16 of the boat.

Also mounted on the transom 11 is a pair of struts 17 each having at one end a transverse axle 18 each end of which bears a wheel 19. The diameter of the wheels 19 is sufficient so that as shown in Figure 2 the stern of the boat, with the outboard engine in its lowered position, is supported on a surface 20 such as a beach or launching ramp with the drive shaft housing 13 and propeller 14 held well clear of that surface.

As shown in Figures 3 and 4 each strut 17 has at one end a slot 22 through which a pin 23 held in a U-shaped bracket 24 projects. The pin 23 holds the strut 17 mounted on the transom 11 while allowing rotation in the direction of arrow X when the pin is at end 22a of the slot 22.

Each strut 17 carries a pair of studs 25 one on each side of the strut and a wedge shaped projecting spar 26. In its lowered position the strut rests in bracket 24 and in another U-shaped bracket 27, with spar 26 positioned beneath the stern of the boat. Each arm of each bracket 27 has a nose portion 28 between which and the transom 11 is defined a notch 29 for receiving a stud 25.

The transom 11 also carries a "Fairlead" plate 31 positioned between brackets 24 and 27 having an aperture 32 connecting with a hole 33 through the transom. The hole 33 has flared ends and a constricted centre portion as shown and carried through the hole is a cord 34, preferably of gun elastic. The dimensions of the centre portion of hole 33 relative to cord 34 should be such that the cord plugs the hole to make it relatively watertight. At its end projecting rearward of the boat the cord 34 carries a threaded plug 35 e.g. of plastics material, which is threaded into a threaded hole 36 in the back face of strut 17. Each bracket 24 and 27, and each plate 31 can be held in place by screws 37,38,39 as shown.

In their raised position as shown in Figure 1 the wheels are held well clear of the water such that they should never under normal conditions adversely affect the performance of the boat by dragging in the water. The wheels may be held firm by clips, ties or the like, not shown.

When it is desired to land, the wheels are released from any securing means and pushed to the rear of the boat. As the wheels fall into the water each strut 17 pivots about its pin 23 and falls to a position trailing behind the boat with pin 23 at end 22a of slot 22. To fix struts 17 in the position shown in Figure 4 the cord 34 is pulled until each stud 25 is wedged in its notch 29 and pin 23 is at end 22b of slot 22. The cord 34 is then secured within the boat by means of a clip, bracketorthe like.

In the lowered position shown in Figure 4the wheels are as shown in Figure 2, and as wheels 19 contact surface 20 the weight of the boat is taken by spars 26. Also, drag on the wheels tending to draw struts 17 away from transom 11 is counteracted by pins 23 and studs 25 held within brackets 24 and 27 respectively.

When a boat with lowered wheels is launched the above precedure is reversed. That is to say cord 34 is released and struts 17 pushed or allowed to drop so that pin 23 is at end 22a of slot 22 and studs 25 are released from notches 29. As the strut and wheel assembly rises in the water it is lifted clear of the water and secured in the position shown in Figure 1.

For a typical engine down clearance of from 9 to 12 inches from the keel of the boat the wheels may have a diameter of 14 inches and a clearance of 2 inches from the keel of the boat. This gives a minimum clearance of 4 inches between the lowermost portion of the housing 13 (typically the skeg - not shown) and the surface on which the wheels rest.

The wheels 19 may be made of plastics material e.g. ones having nylon or polypropylene hubs and neoprene tyres e.g. inflated to 20 p.s.i.

A basic aim of this invention is to provide outboard-engined boats with a retractable landing gear, similar to that used by an amphibian plane landing on a hard runway. The principle of twin wheel bogeys swinging up and down on either side of the engine is simple and the problem of weight bearing is solved by carrying the whole weight of the boat at the rear on spars projecting beneath the boat. Thus the only effective weight bearing members are the spars, the wheel struts, the wheel axles and the wheels. Even a 4 M boat will have the support of 4 wheels, 2 struts and 2 spars. Tested to destruction the first thing to go will be the transom, then the wheels, and then the struts.

As the average distance from cavitation plate to skeg does not vary much between 9" and 12" in engines ranging from 11/2 HP to 100 HP, one single unit will do for all boats of any size, purely multiplying the number of units as necessary.

Securing in the down position is ensured: a) by the studs 25 engaging in notches 29, b) by the pins 23 held in slots 22, and c) by the gun elastic cord 34.

Lowering and raising the wheels takes a matter of seconds and there are no pins, nuts etc. to undo. The process is simple and requires no skill.

If desired one single loop of elastic cord 34 can serve both struts 17.

Claims (8)

1. A boat having a rear transom, an outboard engine attached to the transom and projecting, in a lowered position, below the stern of the boat, and, located on each side of the outboard engine at least one wheel movable from a lower position in which the wheel extends lower than the lowermost part of the outboard engine to a raised position in which the wheel does not adversely affect the performance of the boat.

2. A boat according to claim 1, wherein a pair of wheels are located on each side of the outboard engine.

3. A boat according to claim 1 or claim 2, wherein the wheel or pair of wheels is mounted on a strut which is essentially vertical when the wheels are lowered, and which can be swung about a horizontal axis transverse to the longitudinal axis of the boat and adjacent the upper end of the strut, to raise the wheel or wheel pair to its raised position.

4. A boat according to claim 3, wherein each strut includes a spar which projects beneath the boat when the wheel or wheel pair on the strut is in its lowered position and on which the boat can rest.

5. A boat according to claim 3 or claim 4, wherein each strut is held in an upper and a lower bracket when the wheel or wheel pair on the strut is in its lowered position, the upper bracket including a pivot about which the strut can be swung.

6. A boat according to any one of the preceding claims, wherein the wheel or wheel pair when raised can be secured in a position vertically above the lowered position ofthewheel orwheel pair.

7. A boat according to any one of the preceding claims, wherein the boat has a nose wheel beneath the boat and towards the bow of the boat.

8. A boat according to claim 1 and substantially as hereinbefore described with reference to the accompanying drawings.