AU2008202040A1 - Improved boat hull - Google Patents

Description

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P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990 0 t1oO 0

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Invention Title: IMPROVED BOAT HULL The following statement is a full description of this invention, including the best method of performing it known to me: 00

STITLE

SIMPROVED BOAT HULL 0 FIELD OF THE INVENTION 00 The present invention relates to an improved boat hull. In particular but not exclusively, the present invention relates to a boat hull made from N plastics material which may be made suitably from rotational moulding. The 00oO plastics material is preferably polyethylene.

BACKGROUND TO THE INVENTION Traditionally boats have been made from materials such as wood, metals and fibreglass. These materials each have drawbacks. For example, wood is difficult to maintain, metal is expensive and heavy and fibreglass can become brittle and be easily damaged.

By comparison boats made from plastics material have greater impact resistance than fibreglass boats, are easy to maintain, clean and repair and are less susceptible to marine growth than many other materials.

There remains a need to improve the ride and handling of boat hulls made from plastics material. Australian Patent Application 2004202095 describes a boat that features two spaced longitudinally extending ridges projecting outwardly from the bottom of the boat that have a prominent end adjacent the stern and an opposite end merging flush with the underside inwardly of the bow. These ridges are designed to give cushioned ride characteristics. These ridges only cushion the ride and do not improve the manner in which the boat moves through water.

00 Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or 0 forms part of the common general knowledge in the field.

0O In this specification, the terms "comprises", "comprising" or similar terms are intended to mean a non-exclusive inclusion, such that a method, N system or apparatus that comprises a list of elements does not include those 00 elements solely, but may well include other elements not listed.

OBJECT OF THE INVENTION It is a preferred object of the invention to overcome or at least alleviate one or more of the above problems and/or provide the consumer with a useful or commercial choice.

Further preferred objects will be evident from the following description.

SUMMARY OF THE INVENTION In one form, although it need not be the only, or indeed the broadest form, the invention resides in a boat hull comprising: a body formed of plastics material having a stern and a bow and a pair of opposed side walls and having a hull underside including a pair of generally symmetrical bottom sections separated by a keel characterized in that at the bow said pair of generally symmetrical bottom sections each form an inner substantially planar or flattened area and an outer concavity whereby as the boat hull moves the keel breaks through water which passes over each inner substantially planar or flattened area and each outer 00 0 O concavity to lift the boat out of the water.

The length of each outer concavity in a fore and aft direction may be 0 variable dependent on the size of the boat hull to give a predetermined 00 amount of lift. Thus, each outer concavity may extend to the stern or part way to the stern.

C The boat hull may be V-shaped in front view at the bow and may 00 extend to a stern of the boat hull but more preferably extends partway in a Sfore and aft direction to the stern for example, substantially half way if desired. In this latter embodiment there also may be provided a flat area of the hull underside adjacent the stern.

Each planar or flattened area on each side of the keel may form in totality a generally triangle shaped area with an apex of the triangle in bottom plan view at the bow having an angle of from 200 600 or more preferably 300400 Further features of the present invention will become apparent from the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS To assist in understanding the invention and to enable a person skilled in the art to put the invention into practical effect preferred embodiments of the invention will be described by way of example only with reference to the accompanying drawings, wherein: FIGURE 1 is a top plan view of a boat according to an embodiment of the invention; 00 O FIGURE 2 is rear side perspective view of the boat shown in Figure 1; oO FIGURE 3 is a bottom plan view of the boat shown in Figure 1; FIGURE 4 is a front side perspective view of the boat shown in Figure 1; (N FIGURE 5 is a side elevation view of the boat shown in Figure 1; 00oo FIGURE 6 is a front perspective view of the boat shown in Figure 1; N and FIGURE 7 is a rear plan view of the boat shown in Figure 1.

DETAILED DESCRIPTION OF THE INVENTION As shown in Figure 1, boat hull 100 has a single hull body comprising a bow 102, a stern 104 a port 106 and a starboard 108.

The side perspective view of boat hull 100 in Figure 2 shows that an internal compartment 110 is partially defined by stern wall 112, port wall or side wall 114 and starboard wall or side wall 116. Internal compartment 110 has a floor (not shown).

Turning to Figure 3 hull underside 128 is comprised of port bottom section 118 and starboard bottom section 120 which are joined at keel 122.

The port bottom section 118 is contiguous with port wall 114 and starboard bottom section 120 is contiguous with starboard wall 116.

There is also shown in Figure 2 stern pods 136, walkway 140 and recess 138 for mounting of a frame (not shown) for support of an outboard motor (not shown). Stern pods 136 include horizontal surface 137 and 00 Soblique surface 139.

SBottom sections 118, 120 are joined to the port and starboard walls 0 114, 116, at port chine 124 and starboard chine 126, respectively as best shown in Figure 3. Bottom sections 118, 120 are generally symmetrical and together define a central or inner upwardly extending planar or flattened area S130 on each side of keel 122. The planar or flattened area 130 is 00oo surrounded by an outer concavity 132 which extends substantially to chines N 124,126.

Each upwardly extending inner planar or flattened area 130 and each outer concavity 132 serve to direct water flow such that as boat hull 100 moves, keel 122 breaks the water which then passes over each planar or flattened area 130 before passing over each outer concavity 132. Each outer concavity 132 directs the water in an upward and outward direction which serves to lift boat hull 100 out of the water and improves ride comfort and stability. By lifting boat hull 100 the ride becomes smoother. Each planar or flattened area 130 and each outer concavity 132 do not simply cushion the ride by damping the effects of a rough ride.

As shown in Figure 3 each planar or flattened area 130 in totality has a substantially triangular shape with the apex of the triangle formed at the junction of chines 124 and 126 at bow 102. The base of the triangle may be formed by a straight line but more preferably is formed by lines 111 and 113.

The relative size of each planar or flattened area 130 and of each outer concavity 132 can be chosen depending on the size and weight of the boat and the amount of lift that is desired. The relative curve of each 00 O concavity 132 can also be chosen based on these same factors.

SFigure 3 also shows a plurality of lift strakes 134 which are longitudinal members that run fore and aft on the outside surface of bottom sections 118, oO 120. Lift strakes 134 may or may not extend into each planar or flattened area 130 or each outer concavity 132. The number of lift strakes 134, and N their relative length and width can be chosen based on boat size and weight

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00oo and the amount of lift and stability that is desired.

SFigures 4, 5 and 6 show that hull underside 128 is curved or V-shaped at the bow 102 and substantially planar or flat at stern 104. The transition from curved or V-shaped 146 to flat 148 is best shown in Figure Figure 6 shows a front view of boat hull 100 in which the V-shaped front section 146 of the hull underside 128 can be seen. Figure 6 also shows that lift strakes 134 of boat hull 100 terminate short of the chines 124, 126.

This is also shown in Figure 3.

Figure 7 shows a rear view of boat hull 100 in which area 142, which is a moulding artefact, is visible.

Conveniently, boat hull 100 also features a walkway 140 in the stern wall 112 through which a person can easily enter compartment 110 from the stern 104.

Although boat hull 100 is shown with a single compartment 110, in other embodiments boat hull 100 may have a plurality of compartments.

Boat hull 100 is preferably rotor-moulded from polyethylene. In other embodiments other plastics suitable materials may be used. A person of skill in the art is readily able to select other suitable materials such as, for 00 O example, other suitable plastics materials such as polypropylene.

By providing a boat hull 100 that has a pair of planar or flattened areas 130 and a pair of outer concavities 132 the inventors have provided a oo boat that gives a smooth and comfortable ride through water.

The size of the V-shaped region 146 is important in the boat 100.

1 With a smaller V-shaped region 146 boat 100 will go deeper into a wave, 00oO whereas with a bigger V-shaped region 146 boat 100 will go shallower into a C wave. The size of the V-shaped region 146 can be adjusted based on boat size and conditions in which boat 100 will be used.

Variations in relation to the size and shape of V-shaped area 130 and each concavity 132 can be achieved while still achieving the objective of the invention which is a higher lift out of the water as the boat hull 100 cuts into a wave compared to conventional boat hulls. The boat hull 100 of the invention also has increased comfort and stability. Thus for example, each concavity 132 may extend to the stern 104 if required or at least half-way to the stern.

There is also shown reverse chines or flattened or planar areas 144 which retain the passage of water while the boat hull 100 is in motion essentially in contact with the hull underside 128. The direction of water travel will initially be substantially parallel to keel 122 and due to concavity 132 the water will flow at an angle of about 1350 to the keel direction.

Claims (13)

1. A boat hull comprising: 0 a body formed of plastics material having a stern and a bow and a pair of opposed side walls and having a hull underside including a pair of generally symmetrical bottom sections separated by a keel characterized in (Ni that at the bow said pair of generally symmetrical bottom sections each form 00 an inner substantially planar or flattened area and an outer concavity whereby as the boat hull moves the keel breaks through water which passes over each inner substantially planar or flattened area and each outer concavity to lift the boat out of the water.

2. The boat hull of claim 1 wherein each outer concavity has a length fore and aft which is variable dependent on hull size to provide a predetermined amount of lift.

3. The boat hull of claim 1 or claim 2 wherein each planar or flattened area on each side of the hull forms an area which in totality has a generally triangular shape.

4. The boat hull of any one of the preceding claims wherein there is provided a chine which forms a junction between each side wall and an adjacent generally symmetrical bottom section and each outer concavity extends to an associated chine.

The boat hull of any one of claims 1 4 wherein in front view at the bow there is provided a generally V-shaped region.

6. The boat hull of claim 5 wherein in side view there is provided said generally V-shaped region followed by a flat region at the stern. 00 O

7. The boat hull of claims 5 or 6 wherein a length of the V-shaped region fore and aft is variable depending on boat hull size.

8. The boat hull of any one of claims 1 7 wherein the each inner 0 substantially flattened or planar area extends to the stern.

9. The boat hull of any one of claims 1 7 wherein the each inner Ssubstantially flattened or planar area extends part way to the stern. 00

10. The boat hull of claims 3, 4, 5, 6, 7, 8 or 9 wherein the included angle Sof the generally triangular shape is from 20° 60° at the apex of the triangle.

11. The boat hull of claim 11 wherein the included angle is 30°

12. A mould for producing the boat hull according to any preceding claim.

13. A boat hull substantially as herein described with reference to any one of the embodiments illustrated in the accompanying drawings.