Field of Invention

This invention relates to water craft and particularly to the hulls of water craft such as small boats and in particular dinghies or sailing dinghies that have pram hulls.

Background

Pram hulls are very well known and are frequently used in small boat construction. The blunt bow of a pram hull means that the hull construction as a whole is simple, quick and therefore inexpensive to construct. As such, pram hulls are well known for use in small water craft such as dinghies.

One particularly popular small sailing dingy which has a pram hull construction is the Optimist class sailing dinghy. These dinghies are used by small children throughout the world to introduce them to sailing, and the class is very popular and highly competitive.

The Optimist class dinghy's have some disadvantages. One is that there is still considerable expense involved in purchasing a boat which is essentially a children's' boat and which children tend to quickly grow out of. This is particularly the case because the Optimist class dinghy is a small dinghy, which although good for an introduction to sailing, is quickly outgrown. Moving up to another class involves another considerable investment, and as such is a disincentive to continue with the sport.

Another disadvantage with the pram hold construction is its lack of speed which is partly due to the blunt bow. Yet another disadvantage is that the relatively open construction means that as the blunt bow pushes through waves, these tend to fall over the bow and the result is extensive encroachment of water into the hull. This in turn means that the sailor tends to need to bail constantly while on the water, and again results in reduced boat speed. Object

As an object to the present invention to at least go some way toward overcoming one or more of the above disadvantages. Alternatively, it is the object of the invention to at least provide public with a useful choice. Summary of the Invention

In one aspect of the invention broadly consists in a hull component adapted to engage with the bow of a pram hull. In a preferred embodiment the component comprises a bow extension formed to stream line the bow of a pram hull.

In a preferred embodiment, the bow extension prolongates the waterline length of the pram hull. The bow extension may further be enclosed and buoyant. In embodiments of the invention, the bow extension comprises an acuate bow section and a transition section to transform the bow of the pram hull into an acuate bow.

In one embodiment the component includes a deck portion which is adapted to extend over the bow of the pram hull. The deck portion may further include a water guidance means such as a coaming which assists in prevention of ingressive water into hull in use.

Preferably, force transferring portions along an edge of the deck portion distal to the bow extension are configured to transfer forces between the hull extension and the pram hull. In certain embodiments, the water guidance means is located along the force transferring portions and is shaped to provide stiffness to the force transferring portions.

Preferably, the water guidance means is V-shaped, a tip of the V pointing at the acuate bow section, and two flanges of the V extending to both sides of a plane of symmetry of the hull component. In one embodiment the component include engagement means to engage it with the pram hull. The engagement means preferably releasable so that the bow component can be released from engagement with the pram hull as required i.e. the wall component may be removeable. The engagement means are bolts in some embodiments.

Preferably, the hull component comprises a skirt surrounding a peripheral edge of the deck portion to protect the hull.

Preferably, the hull component comprises a stiffener member extending along the deck portion and along the plane of symmetry of the hull component. The stiffener member may extend from the acuate bow section of the bow extension to the deck portion, wherein the stiffener member is adapted to extend over the bow of the pram hull.

Furthermore, the stiffener member and the V-shaped water guidance may merge at the tip of the V-shaped water guidance. In some embodiments, the deck portion includes a through-hole in a portion of the stiffener member above the bow of the pram hull, the through-hole being adapted to receive a fastening member to fasten the hull extension to the pram hull.

Preferably, the hull component comprises a support member extending from the deck portion along the plane of symmetry of the hull component, the support member being configured to engage with a corresponding feature of the pram hull to transfer forces between the hull component and the pram hull.

The support member may extend from a region of the deck portion adjacent the tip of the V- shaped water guidance in a direction opposite the acuate bow section.

In certain embodiments, the stiffener member and the support member extend from the deck portion at opposite sides thereof.

In another aspect, the invention broadly consists in a boat assembly including

a boat hull having a blunt bow;

at least one hull component as set out above; and

at least one fastening member to removably connect the boat hull and the at least one hull component.

In embodiments of the invention, the boat assembly is a sailing boat. Preferably, the at least hull component is removably interconnected to the boat hull.

In preferred embodiments, the boat assembly can be transformed between two classes of boats by attaching or detaching one of the hull component to or from the boat hull. Preferably, the boat assembly comprises multiple hull components with various bow shapes. Preferably, the hull component comprises a deck portion extending over the boat hull, the deck portion comprising a first through-hole located to be aligned with a corresponding second through-hole in a deck of the boat hull when the hull component is attached to the boat hull, such as to allow for the insertion of the fastening member through the first and second trough- holes.

I preferred embodiments, the hull component comprises a support member configured to engage with a corresponding component of the boat hull to transfer forces between the hull component and the boat hull.

It is preferred that the corresponding component of the boat hull is a seat integrated in the boat hull.

Furthermore, the fastening member and the support member may be spaced apart on a symmetry plane of the hull component to cooperate to resist bending moments acting to tilt the hull component relative to the boat hull.

In another aspect, the invention broadly consists in an extension kit for a sailing boat having a pram hull construction and a mast, the extension kit including a hull component as set out above, and a mast prolongation to attach to the mast of the sailing boat.

Further aspects of the invention will become apparent from the description which will be considered in all its novel aspects.

Drawing Description

Figure 1 A is a sketch of a known pram hull construction

Figure 1 B is a perspective sketch of a pram hull construction which additionally includes a hull component in accordance with the present invention.

Figure 1 is a perspective view of a hull component according to the invention

Figure 2 is a plan view from above of Figure 1

Figure 3 is a plan view from below of the construction of Figure 1

Figure 4 and 5 are front views and rear views respectively of the apparatus of Figure 1 Figure 6 & 7 are side views from the right hand side and left hand side respectively of the construction of Figure 1

Figure 8 is a side elevation and cross section of the construction of Figure 1 .

Figure 9A shows an exemplary load case and force components acting on a hull component Figures 9B and 9C show perspective views of an embodiment of a hull component

Figure 10 shows a side view of an embodiment of a hull component Figure 1 1 shows a side view of an embodiment of a hull component connected to a pram hull construction.

Detailed Description of the Drawings

Referring to Figure 1 A a known pram hull construction 1 is shown. As can be seen, this construction includes a blunt or "transom" bow 2. This general form of construction is well known as it was used in a number of small boats and dinghy's and sailing dinghy's. As discussed earlier in this document, one particular example is the Optimist class sailing dingy. Turning now to Figure 1 B, a construction which includes the pram hull 1 of Figure 1 A together with a hull component 3 in accordance with the present invention. The hull component 3, as can be seen in Figure 1 B, is shaped so as to form a conventional boat bow or prow. As discussed further below, the hull component 3 may optionally include a deck section 4 or portion as is shown in the drawings which partly encloses the bow area of the pram hull construction. Advantages of the invention include the fact that the pram hull is effectively streamlined and therefore can attain greater boat speed. The construction that is proposed in the invention is enclosed and buoyant, and may be made from lightweight materials. The provision of a deck section enables more water to be shed than is otherwise the case with the pram hull construction. Additionally, and significantly, the provision of the hull component according to the invention allows the sailing experience of a pram hull sailing dinghy such as the Optimist to be effectively extended to a new class that has improved performance and can be sailed by larger sailors. In this way, the utility of the Optimist class can effectively be extended. For example this means that a child who owns an Optimist can, at relatively little cost, extend his or her effective sailing lifespan within the Optimist rather than incurring the expense of moving to a whole new class and having to buy a complete new boat.

As another example, a family with two sailing children is able, with the present invention, to allow one child to sail in the Optimist class, and then using the same boat later in the day having the other child sail the same boat as a different class. Hence the invention effectively allows an Optimist class boat to be effectively transformed as required into a different boat.

Turning to Figure 1 , the hull component according to the present invention is shown in perspective view, generally referenced 3. The apparatus 3 has a deck portion 4 and a bow portion 5, which can also be referred to as bow extension 5. As shown, the deck portion 4 may optionally extend rearwardly beyond the bow portion 5 so as to provide in use additional protection from ingress of water into the pram hull to which it is to be attached. Optionally, a coaming 6 shown in dashed outline can be provided on the deck portion to further assist with shedding water which may come over the bow of the whole component 3. Figures 2 and 3 show plan views of the whole component 3 from above and below respectively and Figures 4 and 5 show front and rear views. Further features of the invention can be seen in Figures 6 to 8. As can be seen from the Figures, the bow portion 5 has outer contours in order to provide a streamed hull shape which merges with the hull of the pram construction. Those skilled in the art will understand the various bows shapes and fairing may be used in order to achieve the required object of improved overall hull performance. The preferred embodiment of the drawings is merely one possible example of an appropriate construction.

It can be seen at the rear surface 7 of the bow portion is angled or otherwise shaped so as to substantially conform to the transom bow of the pram hull. Removable interconnection between the hull component 3 and the pram hull can occur in a number of different ways. In the example provided, a number of bolts 8 are provided which can pass through apertures which are made in the transom bow of the pram hull in order to provide a secure attachment. In one embodiment two bolts 8 are provided at a lower portion of the face 7 and a single bolt may be provided at the upper portion of the face 7. Two bolts are provided near the base of face 7 since in use the component 3 is likely to experience upwardly directed forces as it rides through the water.

The hull component 3 may have a skirt 10 surrounding a peripheral edge of the deep portion in order to provide some protection against knocks, to assist with aesthetic appearance of the apparatus and to assist with providing a smooth transition, i.e. essentially match the gunwale area of the pram hull construction which is present in the Optimist class. Additionally, a recess 1 1 may be provided to accommodate the nose of the transom bow of the Optimist hull shape. As can be seen, the hull component 3 allows a seamless transition to be made with the bow of a pram hull craft. As can best be seen in Figure 1 1 , the bow extension 5 prolongates the waterline length w1 of the pram hull by an additional waterline length w2. A longer waterline length means, among other things, a higher theoretical hull speed and thus a more exciting sailing experience. In combination with the bow extension 5 being enclosed and buoyant, as discussed above, the longer waterline length also offers a better performance when the boat dives into waves, and a smoother overall behaviour of the boat. As indicated in the above, Figure 1 B shows that the bow extension 5 comprises an acuate bow section 12 and a transition section 13 to transform the bow 2 of the pram hull, shown in Figure 1 A, into an acuate bow.

In use, i.e. during sailing, a multitude of forces act on the pram hull 1 and on the hull component 3. Turning to Figure 9A, the governing load case of an uplifting force component Fu is shown that is, for example, exerted on the hull component 3 when the boat dives through a wave. This force component Fu effects a corresponding bending moment Mu that needs to be transferred from the hull component 3 to the pram hull 1 in order to prevent or minimise a deformation component δ at an interface 30 (see also Figures 10, 1 1 ) between the hull component 3 and the pram hull construction 1 .

One way to achieve this is to split this bending moment Mu into a pair of forces F1 and F2, separated by and interacting over a distance e. In the shown embodiment, F1 is a tensile force between the hull component 3 and the pram hull construction 1 , and F2 is a compressive force.

In order to transfer the compressive force F2, the hull component 3 includes force transferring portions 20 along an edge 14 of the deck portion 4 distal to the bow extension 5 which are configured to transfer the force F2 between the hull extension 3 and the pram hull 1 . Hence, the resulting force F2 is distributed across the load transferring portions 20 as a line load, as shown in Figure 9A by the respective symbol at f2.

Because the deck portion 4 and thus the force transferring portions 20 extend over the bow of the pram hull 1 , compressive force F2 can be transferred by contact pressure and directly into the pram hull construction 1 .

It is preferred that the water guidance means 6 is located along the force transferring portions 20 and is shaped to provide stiffness to the force transferring portions 20. In the embodiment of Figure 9, the water guidance means 6 is V-shaped, a tip 18 of the V pointing at the acuate bow section 12, and two flanges 16, 17 of the V extending to both sides of a plane of symmetry P1 of the hull component. The plane of symmetry P1 generally also includes the bow section 12, as shown in Figure 9C.

In order to link the forces Fu, F1 , and F2 to act as a bending moment, it is advantageous to provide a high stiffness of the hull extension 3. To this end, the hull component 3 comprises a stiffener member 40 extending along the deck portion 4 along the plane of symmetry P1 of the hull component 3. As will be appreciated by the representation of Figure 10, the stiffener member 40 extends from adjacent to the acuate bow section 12 of the bow extension 5 to a region of the deck portion 4, and is hence adapted to extend over the bow of the pram hull 1 .

To provide optimum stiffness, it is preferred that the stiffener member 40 and the V-shaped water guidance 6 merge at the tip 18 of the V-shaped water guidance 6.

So as to transfer the concentrated load F1 , in preferred embodiments as shown in Figures 9B, 10 and 1 1 , the deck portion 4 includes a through-hole 50 in a portion 43 of the stiffener member 40 that extends over the bow of the pram hull 1 . This through-hole 50 is adapted to receive a fastening member 55 to fasten the hull extension 3 to the pram hull 1 . In preferred

embodiments, the fastening member 55 is a bolt that is received on the side of the pram hull 1 by a second through-hole 60 in a deck of the boat hull 1 . The second through-hole 60 is aligned with the first through-hole 50 when the hull component 3 is attached to the boat hull 1 , such as to allow for the insertion of the fastening member 55 through the first 50 and second trough-hole 60. On a side of the second through-hole 60 facing away from the deck portion 4, the fastening member 55 is locked by means of a washer and a nut (not depicted).

Because the force F2 is transferred by load transferring portions 20, i.e. by mere surface contact and without any additional fastening means, fastening member 55, is the only part of the assembly that requires actuation in the sense that a user, for example, tightens a bolt, and hence the assembly or disassembly of the hull component 3 and the pram hull 1 is quick and reliable.

In certain embodiments, as depicted in Figures 10 and 1 1 , the hull component 3 comprises a support member 70 extending from the deck portion 4 along the symmetry plane P1 of the hull component 3. The support member 70 is configured to engage with a corresponding feature 80 of the pram hull 1 , which is a seat stabilising a mast 81 in the depicted embodiment, to transfer forces between the hull component 3 and the pram hull 1 . Figure 10 shows a vertical component F2' of the forces transferred by the support member 70 which in the load case depicted in Figures 9A and 1 1 , respectively, assists the forces F2 transferred by the force transferring portions 20 in balancing the external bending moment Mu.

As will be appreciated, the support member 70 extends from a region 44 of the deck portion 4 adjacent the tip 18 of the V-shaped water guidance 6 in a direction opposite the acuate bow section 12. In the shown embodiment, the support member 70 has the shape of a knee or a lever. In the shown embodiment, the stiffener member 40 and the support member 70 extend from the deck portion 4 at opposite sides thereof. Figure 1 1 shows that the location where the force component F2' is transferred between the support member 70 and the corresponding feature 80 is spaced apart from the location where load F1 is transferred via the fastening member 55 by a distance h. Hence, any uplifting rotational movement of the hull component 3 caused by an external force Fu can be effectively counteracted by the pair of forces F1 and F2', linked over distance h to exert a stabilising bending moment on the hull component 3, thereby preventing the occurrence of any major gap at the interface 30.

In the embodiment of Figures 10 and 1 1 , it is advantageous that the supporting member 80, the stiffener 40 and the water guidance 6 all meet in a region of the deck portion 4 corresponding to the tip 18 of the V-shaped water guidance 6. In this way, a high stiffness of the hull component 3 is achieved and the parts involved in the force transfer undergo only minimal deformations.

Another aspect of the invention is an extension kit for a sailing boat. As discussed above, such an extension may be desirable when a beginner, having started on a boat with a pram hull construction such as an Optimist, wants to proceed to another class of sailing boat. An extension kit according to the invention includes a hull component as described above in context with Figures 1 to 10, and a mast prolongation to attach to the mast of the sailing boat. The mast extension may be mounted to the mast in several locations. In certain embodiments, the mast extension is a mast tip that is configured to be mounted on a tip of an existing mast of the sailing boat. In embodiments of the invention, the mast tip includes a sleeve portion at a lower end thereof that receives the tip of the existing mast when the mast extension is plugged on the existing mast.

In alternative embodiments, the mast extension is mounted on a foot portion of the existing mast and is hence configured to be mounted between the foot portion of the mast and a

corresponding mounting portion of the hull. In embodiments, the mast extension includes a sleeve similar to the embodiment described above to connect the mast extension to the mast.

According to a third embodiment, the mast extension comprises two sleeves on two distal ends thereof and is configured to be mounted as a section to an existing mast. In this embodiment the existing mast requires to be chopped to insert the mast extension. The mast extension may be made of any suitable material such as aluminium, carbon fibre, wood, or steel. Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like, are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, that is to say, in the sense of "including, but not limited to".

Where in the foregoing description, reference has been made to specific components or integers of the invention having known equivalents, then such equivalents are herein incorporated as if individually set forth. Although this invention has been described by way of example and with reference to possible embodiments thereof, it is to be understood that modifications or improvements may be made thereto without departing from the spirit or scope of the invention.