WO2011095168A1

WO2011095168A1 - Mast foot arrangement

Info

Publication number: WO2011095168A1
Application number: PCT/DK2011/050026
Authority: WO
Inventors: Tue Niels Pii Korremann
Original assignee: Tpk Holding Aps
Priority date: 2010-02-04
Filing date: 2011-02-02
Publication date: 2011-08-11
Also published as: EP2531395B1; EP2531395A1

Abstract

Mast foot arrangement (1) comprising a first member (2) suitable to accommodate a mast or any other upstanding member, where said first member is fixed to a cross member (3), said cross member having a mid section and two end sections arranged at opposite ends of said cross member, and where said first member is arranged orthogonal to the cross member, approximately near said mid-section of said cross members, and whereat either end of said cross member mounting means are provided for fastening said cross member to a support.

Description

Mast foot arrangement

Field of the Invention

The present invention relates to a mast foot arrangement as well as a vessel comprising such mast foot according to the present invention.

Background of the Invention

In the art there are numerous examples of mast foot arrangements. One such example is known from CA 1318188 in which a catamaran construction is disclosed where a rigid aluminium structure is provided in order to bridge and connect the gap between the two hulls of the catamaran. The aluminium structure comprises a number of tubes and T- sections where the T-sections facilitate creating a joint, connecting perpendicular aluminium tubes such that a substantially rectangular structure may be provided. In order to accommodate a mast a further T-section is arranged centrally on a forward tube crossing between the two hulls of the catamaran. The T-section is pivotally mounted on the tube section such that the T-section may be pivoted between a substantially horizontal position in which a mast may be inserted inside the T-section and a vertical position where a mast is arranged in a substantially vertical position. The mast is intended to either be used for carrying a sail or for suspending a tent across the aluminium section between the two hulls. In the embodiment where the mast is supposed to carry a sail, stays are provided connecting upper parts of the mast in its raised position to either of the two hulls of the catamaran whereby the mast is stabilized and maintained in the upright position.

A similar arrangement is known from JP 10-203478 and US 2007/0056494 and US 4102287 wherein the T-section spans between two hulls in a catamaran construction and is maintained in a fixed position by rigid stays fixed to further parts of the rigid aluminium construction which in turn is fixed to the hulls. A further mast foot construction is known from US 3656445 wherein a catamaran is provided with forward and rearward cross members keeping a fixed distance between two hulls in a catamaran construction. The hulls are symmetrical such that in case of capsizing the catamaran it is possible by means of the mast foot to pivot the mast about the forward cross member and thereby elevating the mast and what was previously the bottom side of the vessel such that it is not necessary to overturn the vessel before commencing sailing. The mast foot comprises a mast holder arranged between two disc members which are fixedly arranged to the cross member such that the mast foot may be rotated about the cross member relative to the discs and by inserting a pin through the discs and the mast foot, the mast foot may be locked in a desired position, for example in a vertical position relative to the hulls.

One of the problems with the above-mentioned prior art arrangements is the fact that the mast must be stayed, i.e. provided with support members for example in the shape of wires or tubes supporting/stabilizing the mast by attaching the wire for example halfway up the mast or even further up and fastening the other end of the wire to the side of the vessel or to one of the hulls making up for example a multi-hull vessel. In the art there are plenty of unstayed masts, for example used for windsurfers, but the unstayed mast systems used for windsurfers allows the mast to be pivoted in any desirable direction such that for practical use it is necessary for the user to hold the mast in an upright position in order to utilize the wind- force on the sail.

Further, unstayed mast constructions are known from example US 7137346 wherein a receptable is provided in the vessel, for example in a sailboat roof, in order to accommodate a mast. The forces influencing the mast are thereby accommodated by the receptable and transferred to the constructions surrounding the receptable. This in turn requires a relatively stiff construction surrounding the receptable in that substantial forces may arise in the mast due to the mast's construction itself or to the load deriving from the sail installed on the mast.

A further example is disclosed in US 2008/0245284 wherein a catamaran sailboat is provided with a three degree-of-freedom pivot assembly mast foot for positioning the sail for optimum aerodynamic efficiency. The three degree-of-freedom provides the possibility to possibility to arrange the sail in almost any desired position, but on the other hand requires special means to maintain the sail under control. As suggested a sail mounted ballast is provided. This sail mounted ballast requires a special and relatively expensive mast construction, and furthermore the three degrees-of-freedom requires a non-conventional sail trim system which for many sailors will be foreign and difficult to adapt to.

Object of the Invention

It is therefore an object of the present invention to provide a mast foot arrangement, particularly of the unstayed type, where the mast is securely fastened to the vessel without the need of stays and furthermore where the forces to which the mast is exposed are transferred to the vessel in an optimum manner.

Description of the Invention

The invention addresses this by providing a mast foot arrangement comprising a first member suitable to accommodate a mast or any other upstanding member, where said first member is fixed to a cross member, said cross member having a mid section and two end sections arranged at opposite ends of said cross member, and where said first member is arranged orthogonal to the cross member, and where at either end of said cross member mounting means are provided for fastening said cross member to a support and further that the mounting means comprises a fastening bracket, arranged perpendicular to the longitudinal direction of the cross member, where said fastening bracket extends away from said cross member at least on one side of said cross member and optionally on either side of said cross member, and where said fastening bracket is arranged on said cross member perpendicular to said first member's longitudinal extent.

The first member either being an integral part of the mast or being suitable to receive the mast is fixedly attached to the cross member such that no pivot movement may occur between the cross member and the first member. In this manner, the forces from the mast are transferred to the cross member and consequently to the mounting means arranged in either end of the cross member. By dimensioning the mounting means appropriately it is possible depending on the size of the mast and thereby the forces needed to be transferred through the mast foot arrangement to create a very stiff mast foot arrangement such that an un- foot arrangement such that an unstayed construction may be arrived at. Due to the nature of the construction the cross member will be exposed to substantial torsion forces and for these purposes it is advantageous to select a cross section for the cross member which is torsion resistant such as for example a tube.

The first member or the end of the mast may also comprise an interface section or adapter, which makes it possible to have the first member in a standard configuration irrespective of the mast profile or construction, but by means of the interface or adapter, it is possible to mount any mast to the first member. An important advantage is the fact that the first member and the cross member constructions and its fastening to a vessel, may be utilised in a number of different rig configurations unaltered. As the first member and the cross member must be dimensioned to resist the forces generated by the rig (mast, sail, stays etc) it is advantageous to have as few versions of this construction as possible, as the engineering behind the first member and the cross member is substantial.

The mounting means of the invention further comprises a fastening bracket, arranged perpendicular to the longitudinal direction of the cross member, where said fastening bracket extends away from said cross member at least on one side but preferably on either side of said cross member, and where said fastening bracket is arranged on said cross member perpendicular to said first member's longitudinal extent.

The extent of the fastening bracket away from the cross member substantially in a direction perpendicular to the longitudinal direction of the cross member substantially lessens and distributes the forces which need to be accommodated by the support to which the fastening means are attached. By further providing a bracket extending away on either side of said cross member the bracket will be able to distribute the impact of the forces arising from the mast through the cross member to a larger section of the support such that less impact is transferred from the mast to the support.

The mast foot arrangement will therefore in use provide a stable, fixed footing for a mast and sail. The same mast foot arrangement will provide for easy mounting and raising of the mast, and easy lowering and de-mounting. These aspects are often important for smaller tant for smaller vessels, where transport and/or storage is optimized by disassembling at least part of the vessel.

In a still further advantageous embodiment each fastening bracket in one free end is provided with hinge means, where said hinge means comprises two sections mutually pivotable, where one section is integral with the bracket, and the other section is suitable to be fastened to or integral with a support.

In some embodiments it is advantageous only to have the bracket extending on one side of the cross member. In these embodiments the cross member itself is fastened directly to the support for example by means of a bolt and nut connection, a (stainless steel) fastening strap or the like.

The provision of a hinge construction in one end of the bracket allows for the entire mast foot arrangement to be pivoted when the opposite end of the bracket is not fastened to the underlying support. This is advantageous in that it becomes possible to arrange the mast in the mast foot arrangement in a position where the mast is substantially horizontal which will ease the work in mounting the mast to the mast foot arrangement. Usually the mast foot arrangement will be provided on a vessel, and it might be very difficult to elevate and/or balance a relatively high mast in the vertical position in order to mount it in a mast foot. By being able to tilt the mast foot arrangement around a hinge fastened to the support i.e. thereby around a horizontal axis, it is possible to handle the mast in a substantially horizontal orientation whereby it becomes substantially easier to arrange the mast in the mast foot in a safe and secure manner. The hinge will further facilitate that the mast may be elevated into its usually substantially vertical position simply by elevating the top of the mast whereby the mast and the mast foot arrangement will pivot about the hinges in either bracket.

The hinge construction may be provided by the bracket member comprising an eye part into which the cross member is fitted, such that the cross member may rotate inside the eye part, thereby facilitating the pivotal movement of the cross member relative to the bracket. Due to the rigid construction of the first member of the cross section, the brackets and the hinges, a very stiff and thereby controlled elevation of the mast is facilitated. After the mast has been elevated into the desired position, i.e. the position where the end of the bracket opposite the hinge end is in contact with the support, it is fairly easy to provide means for fastening this end of the bracket, for example by means of bolts and nuts, to the support. In this manner a safe, rigid and very durable connection is created between the unstayed mast and the mast foot arrangement according to the present invention.

In a further advantageous embodiment the support is a mono- or multi-hull vessel preferably a sailing vessel. By sailing vessel shall be understood any vessel carrying a mast, such as for example, but not limited to water, land or ice boats. As already explained above the mast foot arrangement according to the present invention is very rigid and stable and as such will provide a very good and firm foundation for an (unstayed) mast. By further being able to direct the forces through the mounting means, for example in the shape of a bracket, it is possible to distribute the forces to the hull(s) of the vessel in a manner which has little effect on the structural parts of the vessel as such. Furthermore, as the mast foot arrangement according to the present invention is very rigid, it will be possible especially for multi-hull vessels of the catamaran type to use the mast foot arrangement as the forward cross member typically used in catamaran constructions, in that the mast foot arrangement possesses substantial strength due to the strength properties needed in order to accommodate an (unstayed) mast.

Although the invention may be used with unstayed masts, advantages are also gained by using the invention with stayed masts. The stays may be very helpful when raising the mast, i.e. pivoting the mast in the fastening means, in that the stays may be used to pull the mast up into upright position, and also when lowering the mast, a controlled lowering is achieved when the stays are used to brake the masts movement towards horizontal.

In a further advantageous embodiment of the invention the mast foot is integral with the mast where said mast has an aerodynamic cross section, and where the connection between the first member and the cross member and the cross member and the support is sufficient is sufficient to maintain the mast in an upright position.

In a further advantageous embodiment the connection between the first member and a mast allows the mast to pivot about the mast's longitudinal axis, relative to the mast foot.

For this embodiment and in particular when the mast has an aerodynamic cross section it is optimal to be able to pivot the mast according to the sail's position relative to the wind such that the mast will also have a positive contribution to the overall force (lift) generated by the combination of the mast and the sail.

The invention is also directed to a sailing vessel comprising a mast foot arrangement as discussed above where a mast is arranged in said mast foot where the mast is unstayed. By being able to maintain the mast in an unstayed position, i.e. without stays, the installation, i.e. erection of the mast, becomes much easier, faster and less cumbersome in that the stays do not have to be fastened to the sailing vessel and tightened to appropriate tensions or adjusted to appropriate lengths. For regularly stayed masts it is very important to adjust the stays correctly in order to avoid the mast being exposed to an uneven force distribution. These uneven force distributions might be result in the mast attaining an S-shape or a C- shape, instead of the correct linear straight shape to which the mast is designed. As soon as the mast starts to bend there is a significant risk that the mast will be exposed to forces which may damage or cause failure in the mast. By being able to avoid the stays, by using a mast foot arrangement according to the present invention these problems are alleviated.

In a further advantageous embodiment the sailing vessel is a catamaran where the brackets arranged in either end of the cross member are arranged on each hull of the catamaran. As already mentioned above the dimensions of the mast foot arrangement according to the present invention in order to attain a rigid mast foot arrangement fulfilling its purpose is strong enough to serve as a cross member between two hulls in a catamaran construction and as such the mast foot arrangement may "double" both as a mast foot arrangement and as a cross member in a catamaran construction. In a further embodiment recesses are provided in the hull, typically in the deck part of the hull, for for accommodating at least part of the mast foot arrangement. By providing recesses where said recesses are shaped to accommodate the mast foot arrangement, the transfer of forces from the mast and sail to the hull is more rigid and the construction is more stiff, providing improved performance. The tight-fitting recesses allows for a better transfer of forces, and at the same time stiffens the construction such that the hull or hulls in the case of catamarans or trimarans are maintained in a fixed position relative to the cross member (typically 90 degrees). The invention also discloses a method for raising a mast on a single or multi hull vessel using a mast foot arrangement according to any preceding embodiment, comprising the following steps:

a) pivoting the mast foot by means of the hinge into a position where the first member is substantially horizontal;

b) arranging the mast in the first member;

c) pivoting the mast foot and the mast by means of the hinge into a substantially vertical position;

d) fastening the end of the bracket opposite to the bracket end with the hinge, to the support or fastening the cross member to the support .

Especially the provision of pivotable means in the bracket facilitates a very user friendly approach to raising the mast in that the mast as already explained above may be mounted in the mast foot arrangement while the mast is still kept in a substantially horizontal orientation, for example with the top of the mast resting on the ground or a small trolley and the foot of the mast controllably being inserted and fastened to the mast foot arrangement. Alternatively, in embodiments where the mast foot arrangement according to the present invention is integral with the mast the section of the hinge not being integral with the bracket may be fastened to the hull of the vessel prior to elevating the mast such that the mast is securely guided during elevation of the mast and arranged in the correct position from the outset.

Further alterations and modifications of the invention will be evident to the person skilled in the art within the scope of the appended claims. The invention will now be explained with reference to a detailed example as illustrated in the accompanying drawing wherein figure 1 schematically illustrates a mast foot arrangement;

figure 2 illustrates the mounting means in the shape of a bracket;

figure 3 illustrates a mounting bracket including a hinge;

figure 4 illustrates lower section of a mast pivotly arranged to a mast foot arrangement;

figure 5-6 illustrate the invention arranged on a mono- or multi-hull vessel;

figure 7-8 illustrate schematically the hinge tilting mechanism.

Description of the Drawing

In figure 1 is illustrated a mast foot arrangement according to the invention where the mast foot arrangement 1 comprises a first member 2 which is fixed to a cross member 3. The connection between the first member 2 and the cross member 3 is a rigid connection whereby the first member 2 is not movable relative to the cross member 3. In order to fasten the mast foot arrangement 1 to a support (not illustrated) fastening means are provided, in this embodiment in the shape of bolt connections.

The first member 2 is shaped such that it may accommodate a mast, for example a tubular mast, which may be inserted inside the first member 2 or will be fitted concentrically around the first member 2.

In the present embodiment, illustrated in the figures the cross member 3 is illustrated as a tubular member having a circular cross section. The cross member 3, however, may have any cross sectional shape as long as it is possible to accommodate the torsion and bending forces arising due to movement of the mast back and forth and sideways which will be transferred from the mast via the first member to the cross member 3. Furthermore, the weight of the rig, i.e. the mast, boom, sails, etc., resulting in a vertical downward force causing the cross member 3 to bend must also be accommodated by the cross sectional shape and dimension of the cross member 3, such that the forces are transferred to the support through the fastening means 4. For this purpose the cross sectional shape of the cross sectional shape of the cross member 3 may be any suitable shape such as for example circular, triangular, oval, square etc.

Turning to figures 2 a and 2 b the fastening means 4 are illustrated as brackets 5 which brackets are arranged around the cross member 3 in order to fasten the mast foot arrangement to a support. In the brackets 5 are, in this embodiment, arranged two apertures 6 such that bolt means (not illustrated) may be used in order to fasten the bracket 5 and thereby the cross member 3 to a support. In figures 3 a and 3 b is illustrated an embodiment where the fastening means are provided with a hinge 10 where a first section of the hinge 11 may pivot relative to a second part of the hinge 12 which in this embodiment is an integral part of the bracket 5. By fastening the first section 1 1 to the support, for example the hull of a vessel, it is possible to tilt the entire mast foot arrangement as indicated by the arrow 13.

In use, the fastening means 4 will be in a position as illustrated in figure 3 b where the hinge 10 is in a closed position and fastening means are attached between the bracket part 5 b and the support (not illustrated) whereby the mast arranged in the mast foot arrangement as described above will not be able to tilt. Furthermore, due to the rigid structure of the mast foot arrangement the mast may be kept in an unstayed stage in that the mast foot arrangement according to the present invention is able to transfer significant loads to the support on which the fastening means 4 are fastened.

Turning to figure 4 a mast having a schematically aerodynamic cross section is illustrated. The mast is fastened by means of the mast foot arrangement 1 to a ship's hull and the connection between the mast 15 and the first member 2 is such that the mast 15 may pivot about an axis 16 centrically arranged in a circular part of the mast and the first member 2. In this manner it is possible to utilize the aerodynamic shape of the mast as an effective part of the sail surface thereby generating more lift from the combination of mast and sail than what would be achieved with a traditional square or substantially rectangular cross- sectional mast shape.

In figure 5 and 6 are illustrated the mast foot arrangement 1 arranged on a mono -hull 17. 17. The mast foot arrangement is attached to the deck 18 of the mono-hull and will in a traditional manner be able to transfer the forces from the fastening means 4 to the general hull structure 17. In figure 6 is illustrated the inventive mast foot arrangement 1 arranged on a multi-hull in the shape of a catamaran having two hulls 19, 20. Again, the fastening means 4 are attached on a deck portion 21 of each hull such that the loads from the mast foot arrangement and thereby the entire rigging may be transferred and distributed in the general hulls 19, 20.

In figures 7 and 8 are illustrated a situation where the fastening means 4 are provided with hinges as described with reference to figures 3 a and 3 b. When mounted on a vessel 22 which vessel may be mono- or multi-hull, it is possible to tilt the mast 15 as illustrated in figure 7. In this position the fastening means 4 has activated the hinge 10 such that the first section of the hinge 11 remains fixed to the upper surface of the hull 22 whereas the movable section of the fastening means 4 is in a position substantially perpendicular to the surface section of the hull 22. In this position the mast 15 has been brought into engagement with the first member 2 (not illustrated) such that a fixed connection is achieved between the mast 15 and the mast foot arrangement 1 of the present invention. By tilting the mast into the position illustrated in figure 8 and fastening the free section 5 b of the bracket 5 to the surface of the hull the mast is raised in its upright position and securely fastened to an upper surface of the hull 22.

Traditionally, composites such as glass fibre reinforced resins are used when constructing hulls, and as such the invention may also be manufactured from composite materials, preferably Kevlar or carbon fibre reinforced epoxy resins or more traditional materials such as aluminium or stainless steel. As already elaborated on above, especially the connection between the first member and a cross member is exposed to relatively large forces and therefore should be constructed in a way such that the invention may withstand the impact from such forces.

Claims

1. Mast foot arrangement comprising a first member suitable to accommodate a mast or any other upstanding member, where said first member is fixed to a cross member, said cross member having a mid section and two end sections arranged at opposite ends of said cross member, and where said first member is arranged orthogonal to the cross member, and where at either end of said cross member mounting means are provided for fastening said cross member to a support and further that the mounting means comprises a fastening bracket, arranged perpendicular to the longitudinal direction of the cross member, where said fastening bracket extends away from said cross member at least on one side of said cross member and optionally on either side of said cross member, and where said fastening bracket is arranged on said cross member perpendicular to said first member's longitudinal extent.

2. Mast foot according to claim 1, characterised in that each fastening bracket in one free end is provided with hinge means, where said hinge means comprises two sections mutually pivotable, where one section is integral with the bracket, and the other section is suitable to be fastened to or integral with a support.

3. Mast foot according to any preceding claim, characterised in that the first member is arranged centrally on said cross member, approximately near said mid-section of said cross members.

4. Mast foot according to any preceding claim, characterised in that the support is a mono- or multi-hull vessel, preferably a sailing vessel.

5. Mast foot according to claim 1, characterised in that the mast foot is integral with a mast, where said mast has an aerodynamic cross section, and where the connection between the first member and the cross member and the cross member and the support is sufficient to maintain the mast in an upright position.

6. Mast foot according to claim 1 or 5, characterised in that the connection between the the first member and a mast allows the mast to pivot about the mast's longitudinal axis, relative to the mast foot.

7. Sailing vessel, comprising a mast foot arrangement according to any preceding claim, where a mast is arranged in said mast foot, where the mast is unstayed.

8. Sailing vessel according to claim 7, wherein the vessel is a catamaran, and where the brackets arranged in either end of the cross member are arranged on each hull of the catamaran.

9. Sailing vessel according to claim 7 or 8 wherein, in the hull, typically the deck part of the hull, recesses are provided for accommodating at least part of the mast foot arrangement.

10. Method of raising a mast on a single or multi hull vessel using a mast foot arrangement according to any of claims 2 to 6, comprising the following steps:

b) arranging the mast in the first member;

d) fastening the end of the bracket opposite to the bracket end with the hinge, to the support, or fastening the cross member to the support.