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Title:
WATERCRAFT WITH SPONSON
Document Type and Number:
WIPO Patent Application WO/2011/012895
Kind Code:
A1
Abstract:
A watercraft (1) comprising a hull (3), a deck (5) covering at least part of the hull, a member (7, 8) attached to at least part of the periphery of the deck or at least part of the topside of the watercraft, extending away from the hull, the member connecting to or forming a sponson (9, 10), and a means to deploy and retract the sponson. Preferably, the member is rotatably attached to the periphery of the deck, such that the means to deploy and retract the sponson comprises rotating the member between deployed and retracted positions.

Inventors:
ALDISS, William (Christmas Wood Thursford Road,Hindringham,Fakenham, Norfolk NR21 0DP, GB)
Application Number:
GB2010/051240
Publication Date:
February 03, 2011
Filing Date:
July 28, 2010
Export Citation:
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Assignee:
ALDISS, William (Christmas Wood Thursford Road,Hindringham,Fakenham, Norfolk NR21 0DP, GB)
International Classes:
B63B19/08; B63B27/14; B63B39/06; B63B43/14
Domestic Patent References:
WO1991006467A1
Foreign References:
US4320713A
GB1557539A
US20080072811A1
US5937777A
US7644674B1
FR2598670A1
FR2760716A1
JPH0811780A
Other References:
None
Attorney, Agent or Firm:
MIDGLEY, Jonathan et al. (45 Grosvenor Road, St Albans, Hertfordshire AL1 3AW, GB)
Download PDF:
Claims:
CLAIMS

1. A watercraft comprising:

at least one sponson, movable between a retracted position and a fully deployed position, wherein the sponson is above a waterline of the watercraft when in the retracted position; and

means to move the sponson between the retracted position and the fully deployed position. 2. A watercraft as claimed in Claim 1 , wherein the watercraft comprises a deck and the sponson is attached to the deck of the watercraft.

3. A watercraft as claimed in Claim 1 , wherein the watercraft comprises a topside and the sponson is attached to the topside of the watercraft.

4. A watercraft as claimed in any one of Claims 2 to 3, wherein the sponson is rotatably attached to the watercraft.

5. A watercraft as claimed in Claim 1 , wherein the watercraft comprises a hull, and the sponson retracts into a recess in the hull.

6. A watercraft as claimed in Claim 1 , wherein the watercraft comprises a deckhouse, and the sponson retracts into the deckhouse.

7. A watercraft as claimed in any one of the preceding claims, wherein the sponson is also moveable to a deployed position, the deployed position being any position between the retracted position and the fully deployed position, wherein the means to move the sponson can maintain the sponson in the deployed position.

8. A watercraft as claimed in any one of the preceding claims, wherein the watercraft comprises a sponson on each side of the watercraft.

9. A watercraft as claimed in Claim 8, wherein each sponson is moveable independently.

10. A watercraft as claimed in any one of the preceding claims, further comprising a controller, wherein the controller controls the means to move the sponson. 1 1. A watercraft as claimed in Claim 10, wherein the controller further comprises a roll sensor, and the controller controls movement of the sponson based on the roll of the watercraft.

12. A watercraft as claimed in any one of Claims 10 to 1 1 , wherein the controller further comprises a pitch sensor, and the controller controls movement of the sponson based on the pitch of the watercraft.

13. A watercraft as claimed in any one of the preceding claims, wherein the sponson is constructed out of buoyant material.

14. A watercraft as claimed in any one of the preceding claims, wherein the watercraft is a monohull watercraft.

15. A sponson, for use on a watercraft, comprising,

a member arranged to attach the sponson to the watercraft; and

a means to move the sponson, adapted to move the sponson between a retracted position, wherein the sponson is above the waterline of the watercraft, and a fully deployed position. 16. A sponson as claimed in Claim 15, wherein the sponson is adapted to be attached to a deck of the watercraft.

17. A sponson as claimed in Claim 15, wherein the sponson is adapted to be attached to a topside of the watercraft.

18. A sponson as claimed in any one of Claims 16 to 17, wherein the member is adapted to be rotationally attached to the watercraft.

19. A sponson as claimed in Claim 15, wherein the sponson is adapted to retract into a recess in a hull of the watercraft.

20. A sponson as claimed in Claim 15, wherein the sponson is adapted to retract into a deckhouse of the watercraft.

21. A sponson as claimed in any one of Claims 15 to 20, wherein the means to move the sponson is also adapted to move the sponson to a deployed position, the deployed position being any position between the retracted position and the fully deployed position, wherein the means to move the sponson can maintain the sponson in the deployed position.

22. A sponson as claimed in any one of Claims 15 to 21 , wherein the sponson is constructed out of buoyant material.

23. A method of connecting a sponson to a watercraft, the sponson comprising an attachment member arranged to attach the sponson to the watercraft, and a means to move the sponson between a retracted position, wherein the sponson is above a waterline of the watercraft, and a fully deployed position, the method comprising the step of,

attaching the sponson to the watercraft by the attachment member. 24. A method as claimed in Claim 23, wherein the sponson is attached to a deck of the watercraft.

25. A method as claimed in Claim 23, wherein the sponson is attached to a topside of the watercraft.

26. A method as claimed in any one of Claims 24 to 25, wherein the sponson is rotationally attached to the watercraft.

27. A method as claimed in Claim 23, wherein the sponson is retracted into a recess in a hull of the watercraft.

28. A method as claimed in Claim 23, wherein the sponson is retracted into a deckhouse of the watercraft. 29. A method as claimed in any one of Claims 23 to 28, wherein the means to move the sponson can also move the sponson to a deployed position, the deployed position being any position between the retracted position and the fully deployed position, wherein the means to move the sponson can maintain the sponson in the deployed position. 30. A method of deploying a sponson from a watercraft, the sponson comprising a member arranged to attach the sponson to the watercraft, and a means to move the sponson between a retracted position, wherein the sponson is above a waterline of the watercraft, and a fully deployed position, the method comprising the step of,

moving the sponson from the retracted position to the fully deployed position by the means to move the sponson.

31. A method as claimed in Claim 30, wherein the sponson is attached to a deck of the watercraft. 32. A method as claimed in Claim 30, wherein the sponson is attached to a topside of the watercraft.

33. A method as claimed in any one of Claims 31 to 32, wherein the sponson is rotationally attached to the watercraft.

34. A method as claimed in Claim 30, wherein the sponson is retracted into a recess in a hull of the watercraft.

35. A method as claimed in Claim 30, wherein the sponson is retracted into a deckhouse of the watercraft.

36. A method as claimed in any one of Claims 30 to 35, wherein the means to move the sponson can also move the sponson to a deployed position, the deployed position being any position between the retracted position and the fully deployed position, wherein the means to move the sponson can maintain the sponson in the deployed position.

37. A watercraft, sponson and methods substantially as herein described with reference to and as shown in any one of Figures 2-23.

Description:
Watercraft with Sponson

This invention relates to a watercraft. In recent years, there has been increasing demand for renewable energy, such as that derived from the wind. Power generation from the wind utilizes a wind turbine, commonly part of a larger wind farm, which is a large and unsightly structure. As communities do not want their landscape encroached upon with unsightly wind turbines, they are commonly located at sea. Such wind farms are known as offshore wind farms.

The wind turbines in offshore wind farms require maintenance; therefore a crew has to travel to the offshore wind farms, via watercraft, to carry out the maintenance work. Upon arrival at the wind turbine, the crew must be transferred from the watercraft to the wind turbine. Watercraft can comprise either a single hull (monohull) or multiple hulls (multihull). There are advantages and disadvantages associated with both monohull and multihull designs. An example of a monohull watercraft is shown in Figs 1 a to 1 d.

Monohull watercraft create less drag than multihull watercraft. Therefore, less effective horsepower (i.e. the power necessary to overcome the resistive forces) is needed for monohull designs so less fuel is required to power a monohull watercraft (compared to a multihull watercraft). However, monohull watercraft are relatively unstable at rest, and vulnerable to rolling, compared to multihull watercraft. In this context, rolling refers to rotational movement about the longitudinal axis of the watercraft. Accordingly, multihull watercraft create more drag than monohull watercraft and are therefore less fuel efficient than monohull watercraft, but are relatively more stable and less vulnerable to rolling than monohull watercraft. It is therefore an aim of the present invention to provide a watercraft which is fuel efficient and yet suitable for the transfer of crew, for example at a wind turbine.

According to a first aspect of the invention there is provided a watercraft comprising at least one sponson, movable between a retracted position and a fully deployed position, wherein the sponson is above a waterline of the watercraft when in the retracted position, and means to move the sponson between the retracted position and the fully deployed position.

The watercraft therefore has either a deployed or retracted sponson. When the watercraft is travelling to its destination, it is desirable for the watercraft to have a low drag, such that the effective horsepower is reduced and the fuel efficiency of the watercraft is increased. Therefore, when the watercraft is travelling to its destination, the watercraft has a retracted sponson.

When the watercraft requires extra stability, the watercraft can deploy the sponson. The sponson increases the stability of the watercraft. This is advantageous when transferring a person from the watercraft to the wind turbine, as the person will have a more stable platform to move from. This transfer is therefore safer.

Furthermore, when travelling to the wind turbine, or when transferring the person to the wind turbine, it is possible for the person to fall 'overboard' into the surrounding water. In such a situation, it is imperative to retrieve the person as quickly and safely as possible. Retrieval can be effected using the deployed sponson, as the overboard person can hold on to the deployed sponson. Crew on the watercraft can assist in recovering the person holding onto the sponson by retracting it .

Alternatively, if a person has fallen overboard, the sponson can be deployed and a stretcher can be slid down the sponson. Then the person can slide onto the stretcher, and the stretcher can be retrieved from the surrounding water. Preferably, the sponson is attached to the deck of the watercraft. Preferably, the sponson is attached to the topside of the watercraft.

Preferably, the sponson is rotatably attached to the watercraft.

Optionally, the sponson retracts into a recess in a hull, or into a deckhouse of the watercraft. This may be a recess in the hull or a hole in the hull above the waterline.

Advantageously, the member connecting to the sponson is part of the watercraft, and the watercraft can deploy and retract the sponson by rotating the member between deployed and retracted positions. In the retracted position, the sponson is not in contact with the water and therefore the drag of the watercraft is decreased. Furthermore, by retracting the member such that it is substantially perpendicular to the deck, the member can act as a barrier at the periphery of the deck, preventing crew from falling out of the watercraft and water splashing onto the deck. In the deployed position, the sponson is deployed to the water, which increases the stability of the watercraft. In this position, the sponson dampens the motion of the watercraft due to the motion of the water.

Furthermore, with the member in the deployed position, the watercraft has a further stabilizing effect due to water coming onto the top of the deployed member and sponson, thereby forcing the sponson into the water and increasing the damping effect of the sponson.

Preferably, the sponson is also moveable to a deployed position, the deployed position being any position between the retracted position and the fully deployed position, wherein the means to move the sponson can maintain the sponson in the deployed position.

Preferably, the watercraft comprises a sponson on each side of the watercraft.

Preferably, each sponson is moveable independently.

In one embodiment, the first deployed position can be a different position to the second deployed position. Therefore, the first and second sponsons can be deployed to different positions, which may be preferable in turbulent conditions, or when the watercraft is unevenly loaded.

Preferably, the watercraft further comprises a controller, wherein the controller controls the means to move the sponson.

Preferably, the controller further comprises a roll sensor, and the controller controls movement of the sponson based on the roll of the watercraft. Preferably, controller further comprises a pitch sensor, and the controller controls movement of the sponson based on the pitch of the watercraft. Advantageously, the controller can automatically control the deployment and retraction of the sponsons. This saves time and manpower to operate the watercraft. By using roll and pitch sensors, the controller can compute the optimum position to deploy the first and second sponsons in order to achieve maximum stability. The sponson is preferably highly buoyant. The sponson may be formed as a hollow member containing air or some other buoyant material, such as closed cell foam. The sponson may have a combination of materials such as an outer layer of closed cell foam around a hollow inner section. Preferably, the watercraft is a monohull watercraft.

Advantageously, the monohull watercraft will create less drag than a multihull watercraft. As described above, the less drag the watercraft creates, the less effective horsepower is required to power the watercraft. Therefore the monohull watercraft will have improved fuel efficiency with respect to multihull watercraft.

According to a second aspect of the invention, there is provided a sponson, for use on a watercraft, comprising, a member arranged to attach the sponson to the watercraft, and a means to move the sponson, adapted to move the sponson between a retracted position, wherein the sponson is above the waterline of the watercraft, and a fully deployed position. Preferably, the sponson is adapted to be attached to a deck of the watercraft.

Preferably, the sponson is adapted to be attached to a topside of the watercraft.

Preferably, the member is adapted to be rotationally attached to the watercraft.

Optionally, the sponson is adapted to retract into a recess in a hull or into a deckhouse of the watercraft. This may be a recess in the hull or a hole in the hull above the waterline.

Preferably, the means to move the sponson is also adapted to move the sponson to a deployed position, the deployed position being any position between the retracted position and the fully deployed position, wherein the means to move the sponson can maintain the sponson in the deployed position.

The sponson is preferably highly buoyant. The sponson may be formed as a hollow member containing air or some other buoyant material, such as closed cell foam. The sponson may have a combination of materials such as an outer layer of closed cell foam around a hollow inner section.

According to a third aspect of the invention, there is provided a method of connecting a sponson to a watercraft, the sponson comprising an attachment member arranged to attach the sponson to the watercraft, and a means to move the sponson between a retracted position, wherein the sponson is above a waterline of the watercraft, and a fully deployed position, the method comprising the step of, attaching the sponson to the watercraft by the attachment member.

Preferably, the sponson is attached to a deck of the watercraft.

Preferably, the sponson is attached to a topside of the watercraft.

Preferably, the sponson is rotationally attached to the watercraft. Optionally, the sponson is retracted into a recess in a hull or into a deckhouse of the watercraft. This may be a recess in the hull or a hole in the hull above the waterline.

Preferably, the means to move the sponson can also move the sponson to a deployed position, the deployed position being any position between the retracted position and the fully deployed position, wherein the means to move the sponson can maintain the sponson in the deployed position.

According to a fourth aspect of the invention, there is provided a method of deploying a sponson from a watercraft, the sponson comprising a member arranged to attach the sponson to the watercraft, and a means to move the sponson between a retracted position, wherein the sponson is above a waterline of the watercraft, and a fully deployed position, the method comprising the step of, moving the sponson from the retracted position to the fully deployed position by the means to move the sponson. Preferably, the sponson is attached to a periphery of a deck of the watercraft. Preferably, the sponson is attached to a topside of the watercraft.

Preferably, the sponson is rotationally attached to the watercraft.

Optionally, the sponson is retracted into a recess in a hull or into a deckhouse of the watercraft. This may be a recess in the hull or a hole in the hull above the waterline.

Preferably, the means to move the sponson can also move the sponson to a deployed position, the deployed position being any position between the retracted position and the fully deployed position, wherein the means to move the sponson can maintain the sponson in the deployed position.

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

Figure 1 a illustrates a side view of a monohull watercraft of the prior art;

Figure 1 b illustrates a top view of a monohull watercraft of the prior art;

Figure 1c illustrates a front view of a monohull watercraft of the prior art;

Figure 1d illustrates an isometric view of a monohull watercraft of the prior art;

Figure 2 illustrates a side view of a watercraft with retracted sponsons of the first embodiment of the present invention;

Figure 3 illustrates a top view of a watercraft with retracted sponsons of the first embodiment of the present invention; Figure 4 illustrates a front view of a watercraft with retracted sponsons of the first embodiment of the present invention;

Figure 5 illustrates an isometric view of a watercraft with retracted sponsons of the first embodiment of the present invention;

Figure 6 illustrates a side view of a watercraft with deployed sponsons of the first embodiment of the present invention;

Figure 7 illustrates a top view of a watercraft with deployed sponsons of the first embodiment of the present invention;

Figure 8 illustrates a front view of a watercraft with deployed sponsons of the first embodiment of the present invention;

Figure 9 illustrates an isometric view of a watercraft with deployed sponsons of the first embodiment of the present invention;

Figure 10 illustrates a side view of a watercraft with retracted sponsons of the second embodiment of the present invention;

Figure 1 1 illustrates a top view of a watercraft with retracted sponsons of the second embodiment of the present invention;

Figure 12 illustrates a front view of a watercraft with retracted sponsons of the second embodiment of the present invention;

Figure 13 illustrates an isometric view of a watercraft with retracted sponsons of the second embodiment of the present invention;

Figure 14 illustrates a side view of a watercraft with deployed sponsons of the second embodiment of the present invention;

Figure 15 illustrates a top view of a watercraft with deployed sponsons of the second embodiment of the present invention; Figure 16 illustrates a front view of a watercraft with deployed sponsons of the second embodiment of the present invention;

Figure 17 illustrates an isometric view of a watercraft with deployed sponsons of the second embodiment of the present invention;

Figure 18 illustrates a top view of a watercraft with deployed sponsons of the first embodiment of the present invention, showing the wheelhouse;

Figure 19 illustrates a front view of a watercraft with deployed sponsons of the first embodiment of the present invention, showing the wheelhouse;

Figure 20 illustrates a front cross-sectional view of a watercraft with retracted sponsons of the third embodiment of the present invention;

Figure 21 illustrates a front cross-sectional view of a watercraft with deployed sponsons of the third embodiment of the present invention;

Figure 22 illustrates a front cross-sectional view of a watercraft with retracted sponsons of the fourth embodiment of the present invention; and

Figure 23 illustrates a front cross-sectional view of a watercraft with deployed sponsons of the fourth embodiment of the present invention.

Figures 1 a-d illustrate the prior art of a monohull watercraft 1. The watercraft 1 comprises a hull 3, and a deck 5 covering the hull 3.

A first embodiment of the present invention will be described with reference to Figures 2-5. A watercraft 2 is provided in a monohull design. The watercraft 2 comprises a hull 3, including a deck 5 covering the hull 3. References to waterline herein refer to an imaginary line where the surface of the water meets the watercraft 2 when it is stationary in a body of water. The actual water level will change, in use, due to loading of the watercraft 2, movement of the watercraft 2, and movement of the water (e.g. waves).

The part of the hull 3 between the waterline 15a, 15b and the deck 5 is the topside of the watercraft 2.

The skilled reader will understand that when the monohull watercraft 2 is in turbulent waters, or when there is varying distribution of weight on the watercraft 2, the waterline 15a, 15b will vary around the watercraft 2. For example, there is a first waterline 15a on a first side of the watercraft 2 and a second waterline 15b on a second side of the watercraft 2, wherein the waterlines 15a, 15b can be at different levels on the hull 3 of the watercraft 2. The waterlines 15a, 15b can be at the same level around the hull 3 of the watercraft 2, for example, if the watercraft 2 is in calm waters.

The deck 5 comprises a first member 7 at the periphery of the deck 5, extending away from the hull 3. The first member 7 provides a barrier for the persons on the deck 5 from falling out of the watercraft 2, and prevents water splashing onto the deck 5.

Furthermore, the watercraft 2 comprises a second member 8 on the opposite side of the watercraft 2 to the first member 7. In the first embodiment, a part 9 of the first member 7 connects to a first sponson 11 , and a part 10 of the second member 8 connects to a second sponson 12. The sponsons 11 , 12 comprise elongate closed cell members having semi-circular cross sections. The sponsons 1 1 , 12 are moveable between retracted positions and fully deployed positions.

Figures 2-5 show the watercraft 2 with the part 9 of the first member 7 in its retracted position and the part 10 of the second member 8 in its retracted position, that is, such that the sponsons 11 , 12 are above a first waterline 15a and a second waterline 15b of the watercraft 2 respectively. The part 9 of the first member 7, and the part 10 of the second member 8, are rotatably attached to the deck 5 at the periphery of the deck 5, such that the part 9 of the first member 7, and the part 10 of the second member 8, can rotate about the periphery of the deck 5.

The watercraft 2 further comprises means to move the sponsons 1 1 , 12 between its retracted positions and fully deployed positions, preferably by rotating the part 9 of the first member 7 and the part 10 of the second member 8 about the periphery of the deck 5.

When the sponsons 11 , 12 are in their retracted positions, only the hull 3 of the watercraft 2 contributes to the drag of the watercraft 2, therefore the drag of the watercraft 2 is at a minimum.

Figures 6-9 show the first embodiment of the watercraft 2, with the first and second sponsons 1 1 , 12 in their fully deployed positions. The part 9 of the first member 7 rotatably moves from its retracted to its fully deployed position about the rotation point at the periphery of the deck 5. The fully deployed position is any position such that the first sponson 11 is at or below the first waterline 15a of the watercraft 2. The first sponson 11 is rotated from its retracted position to its fully deployed position by the means to move the first sponson 1 1 , such as hydraulic rams.

Likewise, the part 10 of the second member 8 rotatably moves from its retracted position to its fully deployed position about the rotation point at the periphery of the deck 5. The fully deployed position is any position such that the sponson 12 is at or below the second waterline 15b of the watercraft 2. The sponson 12 is rotated from its retracted position to its fully deployed position by the suitable means, such as hydraulic rams.

The means to move the first and second sponsons could also be chains or articulated arms. The means to move the first sponson 1 1 can also move the first sponson 1 1 to a deployed position, the deployed position being any position between the retracted position and the fully deployed position. The means for moving the first sponson 11 can maintain the first sponson 1 1 at its deployed position. Likewise, the means to move the second sponson 12 can also move the second sponson 12 to a deployed position, the deployed position being any position between the retracted position and the fully deployed position. The means for moving the second sponson 12 can maintain the second sponson 12 at the deployed position. The means to move the first and second sponsons 1 1 , 12 could be controlled either by manual control, such as manual operation of the hydraulic rams, or an automatic controller.

The automatic controller could further comprise roll and/or pitch sensors. Thus, the means to move the sponsons 1 1 ,12 reacts to a detected roll or pitch of the watercraft 2 to actuate the sponsons 1 1 ,12.

Furthermore, the controller can calculate the optimal position for the first and second deployed positions as a function of the roll and/or the pitch of the watercraft 2. The optimal position would be such that the stability of the watercraft 2 is maximised.

In the first embodiment, the first and second sponsons, when in their retracted positions, form part of a fender 25 of the watercraft 2, however, this is not essential to the invention. Figures 10-13 show a second embodiment of the present invention. As in the first embodiment, the watercraft 20 comprises a hull 3, a deck 5, a first member 7 and a second member 8, a part 9 of the first member 7 and a part 10 of the second member 8. However, in the second embodiment, the parts 9, 10 of the first member 7 and second member 8 connect to the first sponson 11 and the second sponson 12 respectively, wherein the sponsons 1 1 , 12 do not form part of the fender 25.

As the sponson does not form part of the fender 25, the parts 9,10 of the first member 7 and second member 8 can be a different distance from the deck 5 of the watercraft 20 to the remainder of the first member 7 and second member 8, therefore, the sponsons 1 1 ,12 can be at a greater distance from the watercraft 20. Therefore, the sponsons 1 1 ,12 can be deployed a greater distance from the watercraft 20, which increases stability.

Figures 14-17 show the second embodiment of the present invention, showing the first and second sponsons 1 1 ,12 in their fully deployed positions respectively.

Although the embodiments discussed above comprise two sponsons, a simpler version could comprise a single sponson, deployable to the side or rear of the watercraft. Alternatively, a more complex version could include three or more sponsons deployable variably around the watercraft, for increased stability.

Furthermore, in the embodiments discussed above, the first and second members 7,8 are positioned at the periphery of the deck 5, extending away from the hull 3. Alternatively, the first and second members 7,8 could extend out of the topside of the watercraft 2, away from the hull 3.

Either of the embodiments discussed above could further comprise a wheelhouse 13, for example located between the two sponsons. This feature is shown, in respect of the first embodiment, in Figures 18-19. The wheelhouse 13 reduces the likelihood of a person standing near the parts 9,10 of the first member 7 and second member 8. This reduces the likelihood of the person falling out of the watercraft 2 when the parts 9,10 of the first member 7 and second member 8 are deployed.

Furthermore, either of the embodiments discussed above could include a temporary member (not shown). When a part 9, 10 of a first or second member 7, 8 is deployed, it is possible for water to splash onto the deck 5 of a watercraft 2. This can decrease the stability of the watercraft 2. It is therefore desirable to position a temporary member across the parts 9,10 of the first or second members 7,8, when deployed, to prevent water splashing onto the watercraft 2. This also decreases the likelihood of a person falling out of the watercraft 2.

A third embodiment of the present invention is shown in Figures 20-21. As in the first and second embodiment, the watercraft 30 comprises a hull 3, and waterlines 15a, 15b. However, in the third embodiment, the first and second sponsons 11 ,12 retract into a recess in the hull 3.

Therefore, to deploy the sponsons 11 , 12, the sponsons 1 1 , 12 move from the retracted position to the fully deployed position, where the sponsons 1 1 , 12 are at least partially submerged. The movement can be achieved through extendable members, articulated arms or other suitable means.

A fourth embodiment is show in Figures 22-23. A watercraft comprises a hull 3 and waterlines 15a, 15b. The watercraft 30 further comprises a deckhouse 31 , such as a wheelhouse, and the sponsons 11 ,12 are retracted inside the deckhouse 31. Therefore, to deploy the sponsons 1 1 ,12, the sponsons 11 ,12 move from the retracted position to the fully deployed position, where the sponsons 1 1 ,12 are at least partially submerged.

Again, the movement can be achieved through extendable members, articulated arms, or other suitable means. In all of the embodiments discussed above, the sponsons 1 1 ,12 are constructed out of elongate semi-circular closed cell foam members. However, the sponsons 1 1 ,12 could be constructed out of any material such that they are highly buoyant. The sponsons 11 ,12 may be formed as hollow members containing air or some other buoyant material. The sponsons 1 1 ,12 may have a combination of an outer layer of closed cell foam around a hollow inner section.

The sponsons 11 ,12 could be circular, or any other shape.

Furthermore, the sponsons 11 ,12 may be formed of a plurality of modular sections. Therefore, if one modular section is damaged, then that section can be removed and replaced. This decreases the maintenance cost of the watercraft. The fender 25 of the watercraft may also be formed of modular sections of fender.

The skilled reader will understand that any combination of features of the previous embodiments is possible, without departing from the spirit of the invention.