WO2008136669A1

WO2008136669A1 - Mast assembly, and sailing vessel provided with such mast assembly

Info

Publication number: WO2008136669A1
Application number: PCT/NL2008/050268
Authority: WO
Inventors: Wubbo Johannes Ockels; Jeroen Meijer
Original assignee: Wubbo Ockels B.V.
Priority date: 2007-05-02
Filing date: 2008-04-29
Publication date: 2008-11-13
Also published as: NL1033790C2

Abstract

A mast assembly for a sailing vessel, provided with a mast, a boom and a mainsail, with at least a number of battens included in the mainsail, and the mainsail being provided with a foreleech extending along the mast in hoisted condition of the sail and with a foot extending along the boom in hoisted condition of the sail, while connections are provided by means of which the foreleech of the sail is connected with the mast, wherein the connections are designed as spherical sliding bodies, while the mast is provided with a guide channel in which the spherical sliding bodies are included in hoisted condition of the sail. Also described is a sailing vessel provided with such a mast assembly.

Description

Title: Mast assembly, and sailing vessel provided with such mast assembly.

This invention relates to a mast assembly for a sailing vessel, provided with a mast, a boom and a mainsail, with at least a number of battens included in the mainsail, and the mainsail being provided with a foreleech extending along the mast in hoisted condition of the sail and with a foot extending along the boom in hoisted condition of the sail, while connections are provided by means of which the foreleech of the sail is connected with the mast.

Such a mast assembly is known from practice.

In hoisting and especially striking a mainsail, hindrance resulting from factional resistance between the connections between the mainsail and the mast is to be prevented. For when the wind suddenly rises, it is necessary that the mainsail can be struck fast to prevent the vessel capsizing. Especially when the mainsail is a roached mainsail which is provided with battens extending across the full width of the sail, the danger arises that lowering the sail is hindered by the frictional resistance mentioned. The reason is that with such a mainsail, the battens exert a pushing force on the mast. This pushing force, which can be substantial especially with strong wind, augments the frictional force between mainsail and mast that is to be overcome. Heretofore, these problems were solved using so-called carriages provided with ball bearings. Such carriages are marketed, for instance, by Harken®. Such carriages, however, are costly and moreover cannot be combined with so-called rolling booms. This is because the carriages are arranged on a profiled section from which they cannot be taken off and moreover they are far too large to be wound around a mandrel of a rolling boom. From practice, so-called slides are known for connecting the foreleech of a mainsail with the mast. Such slides are mostly connected with the sail cloth and are certainly not suitable for use in a roached mainsail having battens extending across the full width of the mainsail and exerting pressure on the mast.

Moreover, the known slides have the drawback that they may assume a skewed position relative to the guide section in the mast and may jam as a result. Accordingly, slides also entail the danger that the mainsail cannot be struck fast and smoothly when there is a need for that in case of rapidly rising wind.

The invention contemplates a solution to the above-outlined problems and to that end provides a mast assembly of the type described in the opening paragraph which, according to the invention, is characterized in that the connections are designed as spherical sliding bodies, while the mast is provided with a guide channel in which the spherical sliding bodies are included in hoisted condition of the sail.

Owing to the sliding bodies being spherical, the chance of their jamming in the guide channel through racking or skewing has been reduced to zero.

Moreover, the spherical sliding bodies can swivel in all directions, so that the battens can swivel freely relative to the mast both in horizontal and in vertical direction, substantially without this entailing an increase of the frictional resistance between the sliding bodies and the mast during the up and down movement relative to each other. In an exemplary embodiment of the invention, the boom is a rolling boom, provided with a mandrel around which the mainsail is windable. As the spherical sliding bodies can have relatively small dimensions in all directions, the spherical sliding bodies can be moved out of the guide channel during furling of the mainsail around the mandrel. Around the mandrel there is sufficient space to take up the respective spherical sliding bodies.

By virtue of the spherical sliding bodies, it is therefore possible to combine the particular advantages of a roached mainsail with the particular advantages of a rolling boom. Thus, a greater sailing efficiency is combined with a mainsail convenience. Hoisting and striking the mainsail can be done in a fully automated manner. During hoisting, the spherical sliding bodies automatically find their way to the guide channel in the mast, and during striking the spherical sliding bodies automatically find a position around the mandrel of the rolling boom.

In an exemplary embodiment of the invention, the mainsail is therefore a roached mainsail, with at least a number of battens extending from the foreleech as far as the aft leech. Preferably, the spherical sliding bodies are connected with a batten, so that the pressure force prevailing in the batten is transmitted directly onto the mast via the spherical sliding bodies. To that end, between the spherical sliding body and the batten a connecting piece may be present, which can optionally include a vertical hinge pivot.

Preferably, the distance between each spherical sliding body and the foreleech is equal for all spherical sliding bodies. This enhances the ease with which the sail can be hoisted and struck. To enable this distance to be kept equal and yet to enable setting of the tension of the mainsail with respect to the batten, the mainsail is provided, for the purpose of a batten, with a batten sleeve with a batten tension strap provision by means of which the tension of the sail with respect to the batten contained in the batten sleeve is settable, the tension being settable in that the distance between the aft leech of the mainsail and the end of the batten remote from the mast is settable using the batten tension strap provision.

To protect the sail from weather influences when no sailing is done, it is particularly favorable, according to a further elaboration, when the rolling boom is provided with a hollow boom spar in which the rotatable mandrel is included, with the sail in a stowed condition being wound around the mandrel and situated in the boom spar.

It is possible for the boom to be hingedly connected with the mast. The hinge joint can comprise both a horizontal and a vertical pivot. It is also possible, however, that the boom comprises a boom spar which is fixedly connected with the mast, while the mast is rotatable relative to a hull of the vessel. Such an exemplary embodiment affords ease of operation, certainly when also the jib is provided with a jib spar which is fixedly connected to the mast. Such a mast assembly, known in practice under the name of Aerorig®, provides great ease of operation and, by virtue of the connections designed as spherical sliding bodies, can be combined with a roached mainsail and a hollow boom spar in which a rotatable mandrel is accommodated. The spherical sliding bodies enable complete stowage of the mainsail in the hollow boom spar.

Thus, a high sailing efficiency is combined with great ease of operation.

Preferably, the guide channel in the mast is provided at the lower end thereof with a lead-in which, seen from the top down, widens gradually. Such a lead-in promotes trouble-free guidance of the spherical sliding bodies into the guide channel of the mast when hoisting the mainsail. According to a further elaboration, the lead-in can have a lower end terminating in the interior space of a hollow boom spar of the mast assembly. From the interior space in the hollow boom spar, the spherical sliding bodies can thus be guided to the guide channel in a trouble-free manner.

The invention further relates to a sailing vessel provided with at least one mast assembly as described above.

The invention will presently be further elucidated on the basis of a number of non-limiting exemplary embodiments with reference to the drawing figures.

Fig. 1 shows a side elevational view of a conventionally rigged mast assembly; Fig. 2 shows a similar side elevational view to Fig. 1, with a roached mainsail;

Fig. 3 shows a similar side elevational view to Fig. 1, with a roached mainsail and a pre-bent mast;

Fig. 4 shows a side elevational view of a first exemplary embodiment; Fig. 5 shows a sectional view along line V-V from Fig. 4;

Fig. 6 shows a perspective view of a second exemplary embodiment; Fig. 7 shows an elevational view from line VII-VII in Fig. 6; and Fig. 8 shows a schematic side elevational view with disassembled parts of the connection between the mainsail and the mast.

Fig. 1 shows a side elevation of a mast assembly provided with a mast 1, a boom 2 and a mainsail 3. The mainsail 3 is provided with a number of, relatively short, battens 4. A standard mainsail runs from the clew 5 in a substantially straight line to the head 6. The mainsail 3 is provided with a so-called fore leech or luff 7 which extends along the mast 1. The aft leech 8 is the free edge extending between the clew 5 and the head 6. The foot 9 of the mainsail extends along the boom 2.

Fig. 2 shows a mast assembly with a so-called roached mainsail. In such a mainsail, the aft leech 8 is provided with a curvature. As a result, the surface area of the mainsail is enlarged considerably, which renders the mainsail many times more effective than a conventional rig as shown in Fig. 1. To prevent the mainsail from flogging, especially at the top, it is provided throughout its width with battens 4 extending in horizontal direction. During sailing, these battens 4 exert a pressure force on the mast 1.

Fig. 3 shows an exemplary embodiment where the mainsail has an extreme roach and where the mast 1 is pre-bent. In such an embodiment of the mast assembly, the surface area of the sail with respect to the length of the circumferential edges of the sail is as large as possible. This ratio, called aspect ratio in the sailing world, leads to a more efficient sail being obtained because the positions where turbulence can arise, i.e. near the free edges, which turbulence leads to resistance, are limited to a minimum with respect to the surface of the sail.

As mentioned, the battens 4 of a roached mainsail 3 exert a pressure force on the mast during sailing. To enable rapid striking of a mainsail 3, which is of major importance for reasons of safety, the frictional resistance that needs to be overcome to lower the mainsail 3 along the mast 2 should be as small as possible. To that end, from practice a solution is known which has already been mentioned in the introduction of this specification.

The exemplary embodiment represented in Fig. 4 shows a new solution for the connection of a mainsail 3 to the mast 1. Clearly visible is that the battens 4 at an end proximal to the mast 1 are provided with spherical sliding bodies 10. The mast 1 is provided with a guide channel 11 in which the spherical sliding bodies 10 are included in hoisted condition of the sail 3. On a side of the mast 1 proximal to the mainsail 3, the guide channel 11 is provided with a passage slot 12. The passage slot 12 has a width that is smaller than the diameter of the spherical sliding bodies 10. All this is properly shown in the cross-sectional view V-V represented in Fig. 5. Preferably, the width B of the passage slot 12 is as large as possible, so that a batten 4 can be swiveled relative to the mast 1 through a largest possible angle α. It is also possible, however, to arrange in the connection between the spherical sliding body 10 and the batten 4 a hinge pivot extending substantially in vertical direction, so that the batten 4 can be swiveled between two extreme positions through an angle of 180° or even more.

Especially when the mast assembly is provided with a so-called rolling boom, which is the case in the exemplary embodiment of Fig. 4, the connection between the mainsail 3 and the mast 1 using the spherical sliding bodies 10 comes out well, certainly so when a roached mainsail 3 is involved. The spherical sliding bodies 10, as is clearly visible in Fig. 4, take up little space when the mainsail is wound around the rotatable boom 2. In the exemplary embodiment of Fig. 4, the boom 2 comprises a rotatable mandrel 13 which is connected with the mast 1 so as to be rotatable about its longitudinal axis via a rotation shaft 14. By virtue of a hinge construction 15, the mandrel 13 is additionally connected with the mast 1 for swiveling motion about a horizontal axis 16 and a vertical axis 17. The horizontal axis 16 affords optimum trimming possibilities and the vertical axis 17 affords the possibility of swiveling the mainsail 3 relative to the mast, allowing it to assume a proper position relative to the direction of the wind. Optionally, around the mandrel a hollow boom spar may be provided, in which the sail is received when it has been wound around the mandrel 13. As the sliding bodies 10 are spherical, the chance of their getting stuck in the guide channel 11 due to racking or skewing is minimized. The battens 4 can swivel up, down, to starboard and to port, without the spherical sliding bodies 10 experiencing any extra frictional resistance while moving up or down in the guide channel 11. Preferably, the diameter of the guide channel 11 is approximately 4 mm greater than the diameter of a spherical sliding body 10. With such a clearance, an optimum connection is obtained, while during striking and hoisting a minimal frictional resistance between the spherical sliding bodies and the mast 1 arises. Rapid lowering of the sail, for instance for the purpose of reefing, is possible with the exemplary embodiment shown, even when the wind is strong and so the battens 4 exert a great pressure force on the mast 1.

The spherical sliding bodies 10 are preferably manufactured from a plastic having a low coefficient of friction. The plastic should be resistant to water and hence should not take up any, or hardly any, water. Delrin® (polyoxymethylene or POM) manufactured by DuPont is such a plastic. Plastic moreover has a low specific weight. This is of importance because the weight on the mast should be minimized as far as possible.

The exemplary embodiment of Fig. 6 shows a variant where the boom 2 is not capable of swiveling relative to the mast 1. Such a mast assembly is known in practice under the brand name Aerorig®. The mast assembly is provided with a hollow boom spar 18 having a rotatable mandrel 13 accommodated therein. It is clearly visible that the mainsail is provided with battens 4 which at the ends proximal to the mast 1 are provided with spherical sliding bodies 10. The sliding bodies 10 are situated in a guide channel 11. Fig. 6 shows the mainsail in partly struck condition. It is clearly visible that the sail 3 has been wound around the mandrel 13. It is also clearly visible how the spherical sliding bodies 10 are stowed in the boom spar 18 and the mast 1, around the mandrel. This is still better visible in the view along line VII-VII from Fig. 7. The interior space 19 continuing into the hollow boom spar 18 merges gradually via a lead-in 20 into the guide channel 11 in the mast 1. In Fig. 7 the mainsail 3 is wound partly around the rotatable mandrel 13. The mast 1 is connected with the hull of the vessel (not shown) so as to be rotatable about a vertical axis L. As the lead-in 20 merges gradually, the spherical sliding bodies 10 are guided into the guide channel 11 when the sail 3 is being hoisted. Such a lead-in 20 can evidently be used as well in the exemplary embodiment represented in Fig. 4.

Fig. 8 shows the manner in which the spherical sliding body 10 may be connected with a batten 4 and further shows the manner in which the batten 4 may be included in the mainsail 3. The mainsail 3 is provided with a batten sleeve 21 in which a batten 4 can be received. The batten sleeve is provided with a strap 22 at the foreleech 7. At the free end proximal to the mast, the batten 4 is provided with a connecting piece comprising a sleeve 23, a threaded end 24 and side pins 25. The threaded end 24 serves to connect the spherical sliding body 10 provided with internal thread 26 to the batten 4. The side pins 25 are engaged by the strap 22, while the threaded end 24 reaches through the opening 27 in the strap 22. By virtue of this construction, the distance between the spherical sliding body 10 and the foreleech 7 is equal for all spherical sliding bodies 10, which is of importance with a view to smooth hoisting and striking of the mainsail 3.

To enable setting of the tension of the sail 3 with respect to the batten 4, the batten sleeve 21 is provided, adjacent the aft leech 8, with a batten tension strap provision 28. Using this batten tension strap provision 28, the tension of the sail 3 with respect to the batten 4 can be set. The tension strap 28 engages the free end 29 of the batten 4. The free end 29 may be provided with a kind of notch which prevents the tension strap 28 from sliding off the end of the batten 4. Depending on the tension that is set with the tension strap 28, the batten 4 projects more or less from the aft leech 8 of the mainsail 3. As already noted, optionally, in the batten 4 a vertical hinge may be arranged to realize a larger pivoting angle of the battens 4 relative to the mast 1. Such a hinge could for instance be included in the connecting piece between the spherical body 10 and the batten 4.

It will be clear that the invention is not limited to the exemplary embodiments shown, but that various modifications within the framework of the invention as defined by the appended claims are possible.

Claims

1. A mast assembly for a sailing vessel, provided with a mast, a boom and a mainsail, with at least a number of battens included in the mainsail, and the mainsail being provided with a foreleech extending along the mast in hoisted condition of the sail and with a foot extending along the boom in hoisted condition of the sail, while connections are provided by means of which the foreleech of the sail is connected with the mast, wherein the connections are designed as spherical sliding bodies, while the mast is provided with a guide channel in which the spherical sliding bodies are included in hoisted condition of the sail.

2. A mast assembly according to claim 1, wherein the boom is a rolling boom provided with a rotatable mandrel around which the mainsail is windable.

3. A mast assembly according to claim 1 or 2, wherein the mainsail is a roached mainsail and wherein at least a number of battens extend from the foreleech as far as the aft leech.

4. A mast assembly according to any one of claims 1-3, wherein the spherical bodies are connected with a batten by means of a connecting piece.

5. A mast assembly according to any one of claims 1-4, wherein the guide channel is provided with a passage slot on the side of the mast proximal to the mainsail, while the width of the passage slot is smaller than the diameter of the spherical sliding bodies.

6. A mast assembly according to any one of claims 1-5, wherein the distance between a spherical sliding body and the foreleech of the mainsail is equal for all spherical sliding bodies.

7. A mast assembly according to claim 6, wherein the mainsail, for the purpose of a said batten, is provided with a batten sleeve with a batten tension strap provision by means of which the tension of the sail with respect to the batten situated in the batten sleeve is settable, the tension being settable in that the distance between the aft leech of the mainsail and the end of the batten remote from the mast is settable by means of the batten tension strap provision.

8. A mast assembly according to claim 2, wherein the rolling boom is provided with a hollow boom spar in which the rotatable mandrel is included, while the sail, being an in-boom furling mainsail, in a stored condition is wound around the mandrel and situated in the boom spar.

9. A mast assembly according to any one of the preceding claims, wherein the boom is hingedly connected with the mast.

10. A mast assembly according to claim 9, wherein the hinge connection comprises both a horizontal and a vertical hinge pivot.

11. A mast assembly according to any one of the preceding claims, wherein the boom comprises a boom spar which is fixedly connected with the mast and wherein the mast is rotatable relative to a hull of the vessel.

12. A mast assembly according to any one of the preceding claims, wherein the guide channel, at a lower end thereof, is provided with a lead-in which, seen from the top down, widens gradually.

13. A mast assembly according to claims 8 and 12, wherein the lead-in has a lower end terminating in the interior space of the hollow boom spar.

14. A sailing vessel provided with at least one mast assembly according to any one of the preceding claims.