WO2009074832A2

WO2009074832A2 - Sailing vessels

Info

Publication number: WO2009074832A2
Application number: PCT/GB2008/051178
Authority: WO
Inventors: Richard James Brain
Original assignee: Richard James Brain
Priority date: 2007-12-12
Filing date: 2008-12-11
Publication date: 2009-06-18
Also published as: GB0724224D0; GB2455534A; WO2009074832A3; GB2455534B

Abstract

This invention generally relates to sailing vessels and to methods of providing sail-assist to a vessel. A sailing vessel having a biped mast, said biped mast being hingeably attached to said vessel such that the mast is able to be raised and lowered, said mast having a fore stay and an back stay both attached to said vessel, the vessel further having at least two sails, one said sail being supported by said fore stay and one said sail being supported by said back stay.

Description

Sailing Vessels

FIELD OF THE INVENTION

This invention generally relates to sailing vessels and to methods of providing sail-assist to a vessel.

BACKGROUND TO THE INVENTION

The International Maritime Organization has reported that shipping produces significantly more pollution than aviation at over 1 billion tons per year compared to aviation's about 600 million tons per year. Shipping pollution is set to grow by 75% by 2010.

During the oil crises in the 1970's there were attempts by companies like Walker Wing Sails, and Project Wingship to add sails to maritime shipping. These have not been successful for a number of reasons:

1. In unfavourable winds, large masts create a lot of drag.

2. In gales, masts cause ships to heel, sometimes dangerously.

3. Masts and their pivoting sails take up valuable container space on the deck.

4. Loading and unloading is more expensive, since the cranes that lift containers must work around the masts.

5. Engineers designed taller (and more expensive) masts, some exceeding 100 meters in height, to reduce their number and limit the loss of storage space, but the Panama Canal limits masts to 60 meters.

6. The cost of retrofitting a cargo ship with a row of masts, and strengthening its hull and deck to dissipate the additional stress, was estimated at euro 10m

($ 12.5m), so the sails would have taken around 15 years to recoup their costs through fuel savings. An example of early background prior art relating to a so-called lateen rig is described in US 792,924. Other examples of lateen rigs are described in US 7,267,065 and US 2007/0095267. However lateen rigs such as these suffer from a number of drawbacks. Other examples of background prior art are described in: US 35882; US 2,364,578; US 5,954,007; and US 4,922,846. Examples of "A"-frame and "U¹¹- frame masts are described in US 6,435,118; an example main stay rig is described in US 6,250,242. A foldable mast assembly is described in US 4,940,008. A concept yacht called Amoco Procyon was developed Procyon Inc., described in "Sailing into the future", Design News, 17 June 1991, page 92, This apparently uses a form of "A"- frame mast hinged at the deck; a similar arrangement appears to be described in US 5,083,520. However, in practice it has been found that there are difficulties with this configuration, and in particular with achieving tilt of the mast. Still further prior art can be found in US 6,116,177; US 3,507,240; US 3,827,386; US 3,898,948; US6,990,916; US 2,944,505; US 5,231,943; US 4,934,295; US 1039122; US 4,934,295; US 4,940,008; US 7,267,065; and US 4,886,008. Most of this prior art relates to small boats rather than large ships.

As well as the Walker Wingsail project of Walker Wingsail Systems pic, described above, there was an attempt in Japan by JAMDA and NKK to add ridged square sails to large ships but, unfortunately, a number of these ships were destroyed by strong winds, primarily because the tall masts caused the ships to heel uncontrollably. In Denmark project WindShip also explored the possibilities for sail-assisted commercial ships, but this project was cancelled in 1998. Kite-assisted propulsion has also been explored, for example by the US-based KiteShip and the German-based firm SkySail, but the use of kites has a number of problems, including poor weather survivability, and the collapse of kites with headwinds. We describe techniques which address the problems mentioned above.

SUMMARY OF THE INVENTION

According to the present invention there is therefore provided a sailing vessel having a biped mast, said biped mast being hingeably attached to said vessel such that the mast is able to be raised and lowered, said mast having a fore stay and an back stay both attached to said vessel, the vessel further having at least two sails, one said sail being supported by said fore stay and one said sail being supported by said back stay.

In some preferred embodiments the fore stay and the back stay comprise parts of a single cable, and the mast has a support for the cable over which the cable is able to move. This support may comprise, for example, pulley means. In some preferred embodiments one end of the cable is attached to the vessel via a cable tensioning and release system such as a motor or winch, to allow the mast stays to be tensioned when the mast is in a raised position, and to allow the tension to be released or relaxed to allow the mast to be lowered. Preferred embodiments of the vessel lack a mid-stay. Preferred embodiments of the vessel also include a system to automatically raise and lower the mast, for example one or more hydraulic rams and/or one or more cables to one or more legs of the biped mast. This facilitates remote operation of the mast, for example from the bridge of a large ship.

In some preferred embodiments the biped mast comprises a "U"-shaped or arch-shaped mast (although, potentially, an "A"-shaped mast may alternatively be employed). Such an arrangement allows a top of the sail to be supported under the biped mast and thus enables the sail to be rotatable about a mast stay to which it is attached. This in turn facilitates efficient sail shapes, for example shape in which one more edges such as leading and trailing edges of the sail generally have the form of a portion of a contour of an ellipse. Thus in embodiments the sail has a leading edge which curves away from a stay which supports the sail. In embodiments the shape of the sail is not substantially limited by the rigging.

In some preferred embodiments one or both of the sails is supported by a mast stay other than at an edge of the sail, in particular other than at a leading or trailing edge of the sail. Thus in embodiments a stay supports a sail along a line so as to divide the sail in a ratio of fore to aft area of between 1/6 : 5/6 and 2/3 : 1/3. In some preferred embodiments this ratio is approximately 1/3 : 2/3. An aerodynamic shape for the sail may be maintained, for example, by one or more batons included in the sail. In embodiments the vessel has a keel. It is generally helpful for the vessel to have a relatively large width and, therefore, the vessel may comprises a catamaran or trimaran.

According to a related aspect of the invention there is provided a sailing vessel having a collapsible V or arch-shaped mast, the mast being supported by fore and back stays supporting a sail on at least one of said stays and under said 'u' or arch shape such that the sail is rotatable about said at least one stay.

Embodiments and aspects of the invention as described above are particularly advantageous when providing sail-assist to a vessel with an engine, in particular a large vessel, for example a vessel with a length of at least 15m, 20m, 30m, 50m or 100m.

Thus in a further aspect there is provided a method of providing sail-assist to a vessel having a length of at least 20m, the method comprising providing the vessel with a rig comprising a mast and one or more sails as recited in any preceding claim and using the rig to provide said sail-assist.

In embodiments of the vessel we describe the tilting nature of the mast facilitates its rapid lowering to reduce drag in unfavourable winds and/or to reduce heeling in strong winds. Although in embodiments the sails take up some deck space, this is reduced. Further the moveable mast facilitates access for cranes, and lowering of the mast facilitates large vessels passing under bridges and the like.

In embodiments the mast comprises a multi-piece composite mast, for example with a separate arch section attached to the vertical legs. In embodiments the sails are attached to a form of "wire mast" formed by the fore and back mast stays.

A rig as described above may be retrofitted to a large ship. Thus the invention further provides a method of equipping a sailing vessel with a mast and one or more sails as described above. In preferred embodiments the legs of the mast are attached to the sides of the ship which, with ships of, for example, transverse bulkheads provides a strong attachment point. BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects of the invention will now be further described, by way of example only, with reference to the accompanying figures in which:

Figure 1 shows a vessel in side elevation;

Figure 2 is a front view of the vessel with a generally U shaped mast; Figure 3 is a front view of the vessel with a flat mast top; and Figure 4 shows the vessel from overhead.

DETAILED DESCRIPTION OF DRAWINGS

In figure 1 in this embodiment the biped mast 1 is hingeably 2 attached to the sides of the vessel allowing the mast to be raised or lowered 10. The said mast has a forestay 3 and a backstay 4, comprising parts of a single cable. The said cable is supported 5 by the said mast, which allows said cable to move. The said cable is attached to the vessel 6, and is tensioned or released by a tensioning system 7.

Figure 2 in this embodiment the biped mast 1 has a generally U shaped top, thus allowing the sails 8 to be rotatable under the said mast. Different shaped mast tops can be used, to the same effect.

Figure 3 shows an alternative embodiment where the biped mast 1 has a generally flat top, also allowing the sails to be rotatable under the said mast.

Figure 4 in this embodiment has a winch for the tensioning system 7, the view from overhead shows the sails are rotatable under the mast 11 and 12,

A vessel may have two biped masts, in which case it is preferred that they collapse towards one another. No doubt many other effective alternatives will occur to the skilled person. It will be understood that the invention is not limited to the described embodiments and encompasses modifications apparent to those skilled in the art lying within the spirit and scope of the claims appended hereto.

Claims

CLAIMS:

1. A sailing vessel having a biped mast, said biped mast being hingeably attached to said vessel such that the mast is able to be raised and lowered, said mast having a fore stay and an back stay both attached to said vessel, the vessel further having at least two sails, one said sail being supported by said fore stay and one said sail being supported by said back stay.

2. A sailing vessel as claimed in claim 1 wherein said fore stay and said back stay comprise parts of a single cable, and wherein said mast has a support for said cable over which said cable is able to move.

3. A sailing vessel as claimed in claim 2 wherein said support comprises pulley means, and wherein one end of said cable is attached to said vessel via a cable tensioning and release system.

4. A sailing vessel as claimed in claim 1 , 2 or 3 further comprising a system to automatically raise and lower said mast.

5. A sailing vessel as claimed in any preceding claim wherein one or both of said sails is supported by said stay other than at an edge of the sail.

6. A sailing vessel as claimed in any preceding claim wherein a said stay supports a said sail along a line so as to divide the sail in a ratio of fore: aft area of between 1/6

: 5/6 and 2/3 : 1/3.

7. A sailing vessel as claimed in claim 6 wherein said ratio is approximately 1/3 :

2/3.

8. A sailing vessel as claimed in any preceding claim wherein a top of said sail is supported under said biped mast and wherein said sail is rotatable about a said stay.

9. A sailing vessel as claimed in any preceding claim wherein a said sail has a leading edge which curves away from a said stay.

10. A sailing vessel as claimed in any preceding claim wherein said biped mast has a shaped mast top that allows said sails to rotate around said stays.

11. A sailing vessel as claimed in any preceding claim wherein said biped mast comprises a 'u' or arch-shaped mast.

12. A sailing vessel having a collapsible 'u' or arch-shaped mast, the mast being supported by fore and back stays supporting a sail on at least one of said stays and under said 'u' or arch shape such that the sail is rotatable about said at least one stay.

13. A sailing vessel as claimed in any preceding claim wherein said vessel has an engine and wherein a said sail, in use, assists said engine.

14. A sailing vessel as claimed in any preceding claim wherein said vessel has a length of at least 15m, preferably at least 20m.

15. A method of providing sail-assist to a vessel having a length of at least 20m, the method comprising providing the vessel with a rig comprising a mast and one or more sails as recited in any preceding claim and using the rig to provide said sail-assist.

16. A sailing vessel substantially as herein described and/or as illustrated in one or more of the drawings.