The present invention relates to a water craft and more particularly, to a hull arrangement for a multihull water craft whereby the hull length of the water craft can be varied. Due to it's slow speed, particularly compared with air and road transport, water transport has hitherto been unpopular for passenger services. However, recent developments in vessel design has seen the introduction of multihull wave- piercing catamarans which are capable of travelling at over 30 knots. This has seen the popularity of water transport services steadily increasing. In order to increase the speed at which vessels may travel it is preferable for the hulls to be made narrow and to have considerable length. However, as the length of the hull increases, the manoeuvrability of the vessel decreases. A further consequence of increased hull length is that such vessels are not able to service all ports.

It is an object of the present invention to provide a water craft wherein the hull length of the water craft can be varied. According to the present invention there is provided a water craft comprising a plurality of hulls, each hull including a number of hull sections, said hull sections being connected to the water craft in such a manner that said hull sections can be moved out of, and into, longitudinal alignment whereby the length of the hulls of said water craft can be varied.

Preferably said hull sections of each hull are moveable between a first configuration wherein at least two said hull sections are out of longitudinal alignment so that the length of the hull is at a minimum and a second configuration wherein all of said hull sections are in longitudinal alignment thereby forming said hull.

Preferably when in said first configuration said hull sections are disposed side by side. Preferably when in said second configuration each

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hull section abuts a longitudinally adjacent hull section.

Preferably at least one of said hull sections .is divided longitudinally to form a plurality of divided hulls, said divided hulls being movable between a third configuration wherein said divided hulls are positioned apart .and a fourth configuration wherein said divided hulls are positioned together to form said at least one hull section.

Preferably when in said third configuration respective divided hulls are disposed on opposite sides of one of said hull section.

Preferably each hull includes at least one propulsion unit.

Preferably at least one hull section includes at least one propulsion unit, - Preferably the propulsion units forward of a rear most propulsion unit are arranged so that a corresponding propulsion means extends from a side or bottom wall of said hull section.

Preferably said hull section is provided with a cavity, recess or cutout for accommodating the propulsion means of said propulsion units in a manner so that said propulsion means is contained within the exterior surface of said hull section.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a bottom view of a first embodiment of the water craft in which hull sections for forming two hulls are shown in a first configuration side by side; Figure 2 illustrates the water craft of Figure 1 wherein the hull sections are shown in an intermediate position;

Figure 3 illustrates the water craft in Figures 1 and

2 wherein the hull sections of each hull are shown in a second configuration in longitudinal alignment to form the two hulls;

Figure 4 is a side view of the water craft illustrated in Figure 1;

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Figure 5 is a side view of the water craft illustrated in Figure 3;

Figure 6 is a bottom view of one hull of a second embodiment in which the hull sections are in a first configuration;

Figure 7 illustrates the hull of Figure 6 wherein the hull sections are in longitudinal alignment;

Figure 8 is a front end view of the water craft illustrated in Figures 1; Figure 9 is a front end view of the water craft illustrated in Figures 3, 5 and 7;

Figure 10 is a bottom view of a third embodiment of the water craft in which two hull sections are divided longitudinally and disposed in a third position on opposite sides of other hull sections;

Figure 11 illustrates the water craft of Figure 10 in which the divided hull sections of each hull are arranged together in a fourth position and in longitudinal alignment with other hull sections of the respective hulls; Figure 12 is a bottom view of a fourth embodiment of the water craft in which each hull comprises two hull sections, one of each hull section being divided longitudinally and disposed in a third position on opposite sides of the other hull section of the hull; Figure 13 illustrates the water craft of Figure 12 in which the divided hull sections are shown together in a fourth position in longitudinal alignment with respective hull sections;

Figure 14 is a view from a side of a hull section incorporating two propulsion units;

Figure 15 is a view from the side of an alternate hull section incorporating two propulsion units;

Figure 16 is a view from the side of a further hull section incorporating two propulsion units; Figure 17 is a view from a rear end of the hull section'illustrated in Figure 16; and,

Figure 18 is a view from a rear end of the hull

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section illustrated in Figure 16.

As shown in Figures 1 to 7, a first embodiment of the water craft 2 comprises two hulls 4 disposed side by side beneath a superstructure 6. Each hull 4 comprises two hull sections 8a, 8b (referred to in general as "hull sections 8") . The hull sections 8 can be moved between a first configuration wherein the hull sections 8 of each hull 4 are out of longitudinal alignment in a side by side disposition, as shown in Figure 1, and a second configuration wherein the hull sections 8a and 8b of each hull 4 are in longitudinal alignment thereby forming the hulls 4 as shown in Figure 3. By moving the hull sections 8 between the first and second configurations, the overall hull length of the water craft 2

■ can be varied. In order to allow movement of the hull sections 8, a plurality of longitudinal and transverse rails 10 and 12 respectively are connected to the superstructure 6 of the craft 2. The hull sections 8 are connected with the rails 10 and 12 so as to allow them to move parallel to their length via rails 10 and laterally of their length via rails 12. When in the first configuration, the hull sections 8 are arranged side by side underlying the longitudinal rails 10. To move the hull sections 8 to the second position, the inner most hull sections 8a are moved along the rails 10 in a direction towards the front of the superstructure 6 and the outer two hull sections 8b are moved along other rails 10 in a direction rearward of the superstructure 6. The rearward and forward movement of respective hull sections 8 continues until a rear most position 14 of the forward moving hull sections 8a are longitudinally spaced from a forward most portion 16 of the rearward moving hull sections 8b, as illustrated in Figure 2. The forward moving hull sections 8a are now transported laterally of their length along the transverse rails 12 until they are in longitudinal alignment with the hull section 8b of a corresponding hull 4. The hull sections 8a and 8b of each hull 4 are then moved towards each other so as to abut. In this regard, the forward most portion 16 is arrow shaped and the

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rear most portion 14 is formed with an arrow shaped recess so as to receive the forward most portion 16. The rigidity of the hulls 4 is increased by a support beam 18 which is connected between rear portions of hull sections 8b. A second support beam 20 is connected between forward portions of the hull sections 8a. To allow the lateral movement of hull sections 8a the support beam 20 is in the form of a telescopic elongate element. In order for the hull sections 8 to revert to the first portion illustrated in Figure 1, the above described movement of the hull sections 8 is performed in reverse. From the above, it is apparent that the hull length of the water craft 2 can be varied from a minimum of the length of one hull section 8 to a maximum of approximately twice the length of a hull section P, (refer to Figs. 4 and 5). In a second embodiment of the water craft 2 each hull

4 comprises three hull sections 8a, 8b, 8c (refer Figures 6 and 7) . In the first configuration (Figure 6) hull sections 8a and 8b are located in board of hull section 8c and staggered with hull section 8a forward of hull section 8b. To move hull sections 8a, 8b into the second configuration where they are in longitudinal alignment with hull section 8c, hull sections 8a and 8b are simultaneously and respectively moved forward and rearward longitudinally of hull section 8c. Upon reaching the end of their travel hull sections 8a and 8b are moved transversely of and toward hull section 8c so that all hull sections 8a, 8b and 8c are in longitudinal alignment. Hull sections 8a and 8b can then be moved longitudinal toward each other so as to abut opposite ends of hull section 8c, as shown in Figure 7. A third embodiment of the water craft 2 is illustrated in Figures 10 and 11 wherein each hull 4 comprises three hull sections 8a, 8b and 8c. In a first configuration where the hull length of the water craft 2 is at a minimum, hull sections 8a and 8b of each hull 4 are longitudinally aligned with an arrow shaped forward portion 16 of hull section 8b received in an arrow shaped recess 14 formed at a rear most portion 14 of hull section 8a. The hull section 8c is divided

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longitudinally into divided hull sections 8cl and 8c2, (hereinafter referred to in general as "divided hull sections 8cx") .

When the hull sections 8 are in the first configuration, the divided hulls 8cx are in a third configuration being positioned apart from each other and disposed on opposite sides of hull sections 8a and 8b. Longitudinal rails 10, connected with superstructure 6 and on which hull sections 8a and 8b, are movably mounted allow the hull sections 8a and 8b to move parallel to their length. Divided hulls 8cx are movably mounted on transverse rails 12 which are also provided on the superstructure 6. The transverse rails 12 allow the divided hull sections 8cx to move toward or away from each other. In order to move the hull sections 8a, 8b and 8c into a second configuration wherein the hull length 4 is at a maximum, hull sections 8a and 8b are transported along longitudinal rails 10 away from each other leaving a gap therebetween for accommodating hull section 8c. In this connection, divided hull sections 8cx are transported along the transverse rails 12 to a fourth configuration wherein the divided hulls are positioned together forming hull section 8c. A forward end 21 of hull section 8c is formed in the shape of an arrow and a rear end 22 of hull section 8c formed with an arrow shaped recess. Upon divided hulls 8cl and 8c2 being moved to the fourth configuration, hull sections 8a -and 8b are transported along longitudinal rails 10 in a direction toward each other so that forward end 21 of hull section 8c is received within the rear portion 14 of hull section 8a and the forward portion 16 of hull section 8b is received within the rear end 22 of hull section 8c. In order for the hull sections 8 to revert to the first configuration illustrated in Figure 10 the above described movement of hull sections 8 is performed in reverse. A further variation of the above embodiment is illustrated with reference to Figures 12 and 13 wherein each hull 4 comprises hull portions 8b and 8c wherein hull portion

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8c is divided longitudinally into divided hulls 8cl and 8c2. In a first configuration where the hull length of the craft 2 is at a minimum, divided hulls 8cl and 8c2 are in a third configuration spaced apart from each other and on opposite sides of hull section 8b. In order to move the hull sections 8b, 8c into a second configuration wherein the hull length of the water craft 2 is at a maximum, hull sections 8b, 8c are simultaneously transported along longitudinal rails 10 rearward and forward of the superstructure 6 respectively. Then divided hulls 8c1 and 8c2 are transported in a direction toward each other along rails 12 so as to come together in longitudinal alignment with hull section 8b.

Propulsion units for propelling the water craft 2 can be provided in each hull 4. Spe ^c ifically, propulsion units may be provided in any one or more of hull sections 8a and 8b of the water craft 2. With reference to Figure 14, it can be seen that a hull section 8 includes two propulsion units in the form of water jets 24 and 26. A rear most water jet 24 is arranged so that a propulsion means 28 in the form of a water jet outlet extends from a rear wall 30 of hull section 8. The water jet 26 located forward of water jet 24 in hull section 8 has a corresponding water jet outlet 32 extending from a bottom wall 34 of hull section 8. It is preferable for water jet outlets of hull sections 8 forward of the rear most water jet, to extend from a side or bottom wall of hull sections 8. In alternate arrangement where two or more water jets are used the hull sections can be formed with recesses, cavities or cutouts 36 to accommodate the outlet 32 in a manner so that no drag producing element of the water jet extends beyond the external surface of the hull section, as illustrated in Figures 15 to 18.

In the arrangement shown in Figures 16 and 17 the recess 36 is formed at a rear corner of the hull section 8 with the water jet outlet 32 opening into the recess 36. In another arrangement shown in Figure 18 a recess 36 of Figure 16 is formed centrally of the bottom wall 34 to the rear of the hull section 8. The outlet 32 of water jet 26 opens into recess 36.

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It is apparent from the foregoing description that in a water craft in accordance with the above described embodiments, the hull length may be varied depending on the actual use of the water craft. During docking or port manoeuvring particularly where a craft must operate in a confined space the hull sections 8 can be moved out of longitudinal alignment into a first configuration so that the hull length can be reduced. During open water cruising the hull sections 8 of each hull 4 are moved into longitudinal alignment thereby providing a maximum hull length. Such hull arrangements allow the water craft to achieve higher speeds and/or bigger pay loads and/or decreased fuel consumption in varying degrees over that which would be available on fixed hull length water craft. . Now that preferred embodiments of the water craft 2 have been described in detail, it will be apparent to those skilled in the relevant arts that numerous modifications may be made to the water craft 2 without departing from the basic inventive concepts. For example, in the illustrated embodiments, when the hull sections 8 are in the second configuration in longitudinal alignment, the ends of adjacent hull sections are illustrated as being in abutment. However, a gap may exist between such ends. Furthermore, although the hulls 4 are illustrated as comprising two or three hull sections, each hull 4 may be comprised of any number of hull sections. In addition, the hull sections 8 are illustrated as being movable along longitudinal and transverse rails 10 and 12. However, any other means such as rollers or other guides may be used in order to facilitate the movement of the hull sections 8. With reference to propelling the water craft 2 it is further apparent that although.not illustrated, divided hull section 8cx may also be provided with such propulsion units. However, given the reduced volume of each divided hull section 8cx, the propulsion units which may be fitted thereto will necessarily be smaller than that which can be provided in hull sections 8a and 8b. Also, although the propulsion units are illustrated as being water jets, other propulsion systems may

be used. While the hull sections 8 are shown with arrowed shaped ends and arrow shaped recesses it is of course possible to form abutting adjacent ends of the hull section with any complementary shaped protrusions and recesses. Finally, the hull sections 8 need not be of the same length, so that in the first configuration the minimum hull length of the water craft 2 is the length of the longest hull section provided shorter hull sections are located within the length of the longest hull section. Although when in the first configuration the hull sections 8 are shown with a space between adjacent hull sections, the hull sections can be arranged so as to abut an adjacent hull section. All such variations and modifications are to be considered within the scope of-the invention, the nature of which is to be determined from the foregoing description and the appended claims.

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