WO2003045773A2

WO2003045773A2 - Mast system for sailing boats

Info

Publication number: WO2003045773A2
Application number: PCT/DE2002/004301
Authority: WO
Inventors: Ursula Hoffmann
Original assignee: Ursula Hoffmann
Priority date: 2001-11-24
Filing date: 2002-11-22
Publication date: 2003-06-05
Also published as: EP1448432A2; WO2003045773A3; DE10157730A1; AU2002365286A1

Abstract

The invention relates to a mast system for sailing boats comprising at least one hull (4) and at least one mast (2) which is fixed by means of a mast foot (8) fixed to the hull. According to the invention, a) either the mast foot (8) can be pivoted about an axis which is parallel to the longitudinal axis (9) of the boat and, when sailing either against the wind or with the wind, the mast (2) can be respectively oriented approximately in the vertical direction; or b) two masts (2, 2') are provided, said two masts being arranged in such a way that they are symmetrical in relation to the central plane (3) of the boat, said central plane intersecting the longitudinal axis (9), and either the tips (16, 16') of the masts are inclined towards the central plane (3) of the boat, or a fixed sail (= carrier surface) is pivotally fixed in the region of the tips of the masts by means of a joint.

Description

MASTER SYSTEM FOR SAILING BOATS

The invention relates to a mast system for sailboats with at least one boat hull and at least one mast, which is fixed by means of a mast foot attached to the boat hull.

The history of sailing ships is many thousands of years old. Rowing ships were equipped with sails as early as the Bronze Age. The training of masts and sails is correspondingly diverse. Depending on their size, these sailing ships have one, two or more masts, the sails being in their rest position either longitudinally or transversely. Known sailing ships with several masts are the tall ships of the last century, while the ships used today mostly have only one mast. The best known types of ships and boats of this type include

Yachts and dinghies.

In all sailing ships or boats according to the prior art, the mast or masts are arranged in the central plane running through the longitudinal axis of the boat and point in a direction perpendicular to the deck, whereby

Mast and boat are rigidly connected. This arrangement means that when sailing on the wind or with clear wind, the boat and thus the mast tilt to the side in the lee direction. The inclination of the mast has the consequence that the sail surface opposite the wind becomes smaller, since with increasing inclination of the boat the projection of the sail surface perpendicular to the water surface decreases. This also disadvantageously reduces the propulsive force transferred from the wind to the boat.

The mast designs known from surfboards also belong to the state of the art. In these sailing vehicles, the mast is articulated to the hull by means of a mast foot. This design enables the mast to be swiveled in all spatial directions in the half-space above the surfboard. The free mobility of the mast enables the sail to be always positioned optimally in the direction of the wind and quick maneuvers to be carried out with the sail. The surfers on the other hand must keep the mast and sail permanently in balance with the wind forces. Since he has to compensate the wind forces in full size with his own physical strength, the surfers are disadvantageously required a comparatively large amount of force.

Proceeding from this, the object of the invention is to provide a mast system which avoids the disadvantages of known systems mentioned, moreover leads to greater propulsive forces, therefore gives the sailboat higher speeds and thus facilitates the transition from the displacement to the sliding state.

This object can be achieved according to the invention by two different mast systems. The first solution is characterized in that

- The mast foot is pivotable about an axis parallel to the longitudinal axis of the boat, and when sailing on the wind or with clear wind the mast - regardless of the heel of the boat - can be aligned approximately in the vertical direction.

In deviation from the usual arrangement of the mast on sailing yachts and dinghies, the invention provides a pivotable mast foot which is fastened to the boat hull and receives the mast. The pivoting takes place about an axis parallel to the longitudinal axis of the boat. The mast and the sail attached to it can thus be pivoted in a plane perpendicular to the axis mentioned on both sides of the boat, while its distance with respect to bow and stern is essentially maintained when pivoting.

This version of the mast is used according to the present invention in such a way that when sailing with lateral wind, the mast is permanently held in a vertical position regardless of the heel of the boat. A core idea of the invention thereby take the Opposite wind area and thus the propulsive force generated by the sail is an optimal size.

By looking at the wind and sailing forces in a first approximation, these processes can be described in a simple manner. In the above

Approximation is considered the sail as a flat surface and the wind flow is broken down into a component parallel and perpendicular to the sail surface. In this (!) Approximation, the flow parallel to the sail area means that no forces are transferred to the sail and therefore the sailboat, since it sweeps along the canvas without any effect. When the mast is in a vertical position, the force K acting perpendicularly on the sail is:

K = F • p where F represents the area of the sail and p denotes the dynamic pressure p • v ^2/2 with p the density of the flow medium and its velocity v.

The force standing vertically on the sail can be broken down into a component in the direction of the boat's longitudinal axis and a component perpendicular to it. If one designates the angle between the longitudinal axis of the boat and the vertical on the sail with φ, the result is

the propulsive force VK to VK = cos φ • K = cos φ • F • p (1a) and the shear force QK to QK = sin φ • K = sin φ • F • p (2a)

The propulsive force points in the longitudinal direction of the boat, thus driving the boat, while the transverse force acts perpendicularly to it and causes the boat to drift sideways and the boat to heel about its longitudinal axis. The equations apply to a vertical position of the mast, which, according to the invention, is assumed independently of the heeling of the boat in each case.

In the case of mast designs according to the prior art, a heel of the boat leads to the mast tilting towards the lee side. The sail surface opposite the wind is thus the one perpendicular to the water surface Replace projection of the surface. With an angle of inclination α of the mast against the vertical, the size F -cos replaces F in the last two equations. This is used for sailboats with a conventional mast arrangement

the propulsive force VK to VK = cos φ • cos α • F • p (1b) and the shear force QK to QK = sin φ • cos α • F • p (2b)

As the comparison of equations (1a) and (1b) shows, the mast system according to the present invention has a generally greater propulsive force.

The advantageous consequence of this is that the boat reaches a higher speed and thus slides more easily.

However, an increase in the propulsive force also has the consequence, as the comparison of equations (2a) and (2b) shows, that the lateral force increases to the same extent and thus increases the drift and heeling compared to the prior art. The enlarged section can be countered in a simple manner by a corresponding enlargement of the keel or sword. Remedy for an enlarged heel is provided by further features of the invention.

As a result, in a boat equipped with the mast system according to the invention, the effective sail area is given by the complete sail area in every wind direction and at every heel. In this way, higher speeds can be achieved with boats equipped in this way than with conventionally equipped boats, without, on the other hand, as with surfing, high physical strength being required.

In a preferred development of the proposed mast system, the mast foot is designed to be displaceable in the lee direction. It can therefore be moved from the position in the middle of the boat to a position on the edge of the boat in which, given the heeling of the boat, it is at a smaller distance relative to the water surface than in the middle of the boat. This also brings the mast and the sail attached to it into a comparatively low position above the water surface. Accordingly, the lever arm between the center of gravity of the sail and the at Heir effective, about the height of the water surface pivot point of the boat is reduced. For the torque which is responsible for the heeling or possibly tipping of a boat and which is given by this lever arm and the transverse force acting in the center of gravity of the sail, the result is approximately unchanged compared to the prior art

Size, since the reduced lever arm and the lateral force increased according to equation (2a) together have a neutral effect. The advantageous consequence of this is that, despite the increased lateral force, the tendency to heel and the risk of the boat tipping over have not changed in the present mast system.

The above consideration of the forces is only a first approximation. If the calculation is more accurate, the currents of the wind towards the sail must also be taken into account. With state-of-the-art sails, they also contribute to a considerable propulsion of the boat. This stems from the fact that modernly cut sails have a bulbous shape, the cross section of which is comparable to the profile of an airplane wing. As a result of this training, suction is created on the side of the sail belly due to negative pressure, which also leads to propulsion of the boat. This property also comes into play in the mast system according to the present invention in the proposed mast position, of course, in that the flow sweeps sideways around the sail. According to a feature of the invention, however, it is also provided that the mast permits pivoting beyond the vertical and can be inclined toward the windward side. Through this training, the bulbous shape of the sail is also used for propulsion by currents that cross the sail. As long as the mast and sail inclination in the direction mentioned does not exceed a certain amount, the gain in propulsive forces due to the suction effect outweighs the loss due to a reduction in the effective sail size due to the sail inclination in the windward direction. This results in a further gain in speed for the boats with the proposed mast arrangement.

A useful further development has the object that the mast foot and thus also the mast can be pivoted about the transverse axis of the boat as the axis of rotation. The movement takes place in the longitudinal direction of the boat. Already Small swivel angles are sufficient to optimally trim the boat. Here, the term "small angle" means a swivel angle below 20 °.

In the second solution of the object on which the present invention is based, a system of two masts is provided, which are arranged symmetrically to the central plane running through the longitudinal axis of the boat and whose mast tips are inclined towards the central plane of the boat. When sailing on the wind or when the wind is clear, it is recommended to hoist the sail on the leeward mast. As a result of the heeling of the boat, since the tip of the mast is inclined towards the median plane of the boat, it assumes a vertical orientation. As with the first solution, the sail surface facing the wind takes on a great value. In the standard version of this mast system, the entire length of the mast is fixed relative to the hull, so that an adjustment of the

Mast inclination at different heelings of the boat did not occur. The mast is aligned so that the mast is vertically aligned with a medium heel. The advantage of this solution can be seen particularly in the simple technical implementation. In both solutions, the term "sail" is to be interpreted broadly and includes flexible foils as well as rigid wings.

In a further development of this solution, analogously to the first, it is provided that the mast feet of the two masts can each be pivoted about an axis parallel to the longitudinal axis of the boat, and when sailing on the wind or with clear wind the mast lying leeward is independent of the heel of the boat can be aligned in the vertical direction. The same considerations and advantages apply for the leeward mast plus sail as for the leeward movable mast according to the first solution. In particular, the effective sail area is with every wind direction and with every one

Heeling given by the entire sail area and the tipping moment around the pivot point of the boat, which is approximately at the level of the water surface, due to the lateral force acting on the sail, approximately the same as that of conventional mast systems. According to a feature of the invention, it is also proposed in the system consisting of two masts that the leeward mast swivels beyond the vertical and can be inclined toward the windward side. The advantage of this training, as already shown, is that the current flowing across the sail leads to an additional propulsion of the boat.

The variant of the mast system with two single masts inclined towards each other also has advantages when sailing with aft wind. In this course, one is equipped with the mast system according to the invention

Boat proposed to set sail on both masts and preferably to provide additional sails between the two masts. By gaining additional sail area due to the second sail and the additional sails between the masts, a corresponding gain in speed is achieved. In addition to the proposed sail arrangement, the spin field frequently used when sailing in front of the wind can of course also continue to be used.

In a further solution to the underlying task, which has numerous parallels with the above-described, a rigid sail is pivotably attached in the area of each mast tip via a joint. In an aerodynamic sense, this rigid sail, due to its geometric design, acts like an airfoil, i.e. that the flow path and thus the flow speed of the surrounding air develop on both sides of the sail at different values, so that a comparison of both sides of the sail creates a pressure difference which exerts a force effect on the sail itself. In addition to the use of a rigid sail (= wing), the attachment via a joint on the mast is crucial. To ensure a largely free mobility of the sail, the attachment in the area of the outer end of the mast must take place in the area of the mast tip.

The attachment via a joint ensures the relative pivotability of the sail relative to the mast, the setting of a particular sail being completely independent of the neighboring one. This is another decisive advantage of the inventive concept. The use of rigid sails (= wing) also allows the creation of optimal propulsion conditions. Due to the formation of the joint, e.g. B. as a gimbal or ball joint, as well as by appropriate choice of dimensions of the wings, it is preferred that each of the rigid sails with its main plane can be aligned approximately in both the horizontal and the vertical plane.

There are numerous options for using the mast system described above. The rigid sails can thus be aligned essentially parallel to one another, a synchronous adjustment being conceivable. In deviation from this, a crucial proposal goes there, both

Align sails differently. The wing facing the wind, i.e. on the windward side, is aligned essentially vertically, so that in relation to the mast, an arrangement of the sail is obtained which - apart from the rigidity of the wing - can be achieved with conventional sailing boats, especially small sailing boats, such as Dinghies or yachts, a comparable spatial arrangement results. Functionally, this sail is used to generate propulsion. The other sail, and therefore the wind-facing sail, the leeward sail, is, however, aligned essentially horizontally, so that a pronounced wing effect is formed, which results in buoyancy. The advantages to be achieved in this way are particularly evident in the case of more multihull boats. It can be seen there that, due to the wind forces acting on the sail, not only propulsion but also a tipping moment about the longitudinal axis is generated, which leads to the lifting of the windward hull so far that the water contact can be completely lost. The leeward hull, on the other hand, is pressed all the more into the water and this creates a further flow resistance that hinders propulsion. If the lee-side sail creates a noticeable buoyancy component by aligning it in the horizontal plane, the hull on this side is raised more or less from the water and the propulsion resistance in the water is largely reduced. The importance of this measure becomes clear when you keep in mind that the resistance to movement of the leeward hull in the water limits the realization of high speeds. By arranging the leeward sail in intermediate positions, an opti- Realize the adjustment of the buoyancy and propulsive forces according to the specific conditions on site.

The mast system according to the invention can advantageously be used on a boat with a boat hull, such as a yacht or a dinghy, but it is also suitable for use on a boat with several boat hulls, such as a catamaran or a trimaran. The present invention provides both uses. In the latter application, in the variant of the mast system with two individual masts according to one feature of the invention, provision is made in particular for the two masts to be fixed in each case to the boat hulls which are the most widely spaced apart. This training leads to the fact that the leeward mast takes the lowest possible position above the water surface when the boat is heeling. This also minimizes the overturning moment around the pivot point located in the water surface and increases the stability of the boat accordingly.

Another proposal according to the present invention also serves the goal of improved stability. This provides, on both sides of the boat body, preferably retractable floating bodies, the exit of which in the

Direction perpendicular to the longitudinal axis. The floating bodies increase the safety of the boat against tipping over, the stability increasing with increasing distance between the floating bodies and the actual boat body.

The term "sailing boat" in the sense of this application is to be interpreted broadly and includes not only sailing boats in the narrower sense, ie those that are in contact with water, but also those vehicles that are moved by land with wind power. These include ice sailers moving on ice surfaces as well Sand sailors that move over a sandy area by means of a landing gear under the influence of wind power. Further details, features and advantages of the invention can be found in the following part of the description. In this part, an embodiment of the mast system according to the invention is explained in more detail with reference to a drawing. Show it:

Figure 1: a cross section through a boat with the mast system according to solution one

Figure 2: a cross section through a boat with the mast system according to solution two.

In Figure 1, a sailboat according to solution one is shown that sails on the wind. The direction of travel of the boat points out of the plane of the drawing, the direction of the wind is given by arrow 1. The boat is equipped with a mast 2, which is moved leeward out of the central plane 3 of the boat hull 4 in the direction of the boat edge 5. The displacement device is to be indicated by the bolt 6 and the parallel slide rails 7. The mast is articulated on its base 8 and is designed to be pivotable about the bolt 6 in a plane perpendicular to the longitudinal axis 9 of the boat. The pivoting takes place in the windward direction and is adjusted so that the mast 2 assumes a vertical orientation regardless of the heel of the boat hull 4. In this setting, the mast is held by a bracing 10. In the vertical position of the mast 2, the effective area of the sail 11 corresponds to the complete sail size, this relationship being independent of the heel of the boat hull 4. This also maximizes the propulsive force exerted by the wind on the sail, with such

Boats equipped with masts therefore reach higher speeds than conventionally equipped boats.

The off-center position of the mast also leads to the mast 2 and the sail 11 attached to it being a comparatively low position above the

Water surface 12 occupies. Compared to a mast attached in the center plane of the boat hull 4, the mast arranged according to the invention has a mast base 8 lying lower by the distance 13. By the same amount, the distance 14 of the center of gravity 15 of the sail 11 from the water surface 12 is compared to a conventional arrangement of the Mastes downsized. The torque from this distance 14 and the transverse force acting in the center of gravity, which is responsible for the heeling of the boat and in extreme cases for the boat tipping, remains approximately unchanged in the proposed arrangement of the mast, since the decrease in the lever arm 14 increases the transverse force in the present

Mast arrangement corresponds.

Figure 2 shows the variant of the mast system with two inclined individual masts 2, 2 'again. Both masts are arranged symmetrically to the central plane 3 running through the longitudinal axis 9 of the boat, with their

Mast tips 16, 16 'are inclined towards the central plane 3 of the boat. The illustration shows a boat sailing with aft wind, the direction of travel and the wind direction are assumed to point perpendicular to the plane of the drawing. For sailing in front of the wind, sails 11, 11 'are advantageously hoisted on both masts 2, 2'. As the drawing shows, a further sail 11 ″ is provided between the two masts. The sails 11, 11 ′ and 11 ″ overall represent a comparatively large sail area, which enables a fast journey against the wind. If necessary, in addition to these sails, the one that is often used when sailing in front of the wind can also be used without any problems. Spinager ?? deploy.

Claims

PATENT CLAIMS

1. Mast system for sailing boats with at least one boat hull (4) and at least one mast (2), which is attached to the boat hull by means of a

Mast foot (8) is fixed, characterized in that the mast foot (8) can be pivoted about an axis parallel to the longitudinal axis (9) of the boat, - and when sailing against the wind or with clear wind the mast

(2), regardless of the heeling of the boat, - can be aligned approximately in the vertical direction.

Mast system for sailing boats according to claim 1, characterized in that the mast base (8) can be moved in the leeward direction.

3. Mast system for sailboats according to claim 1 or 2, characterized in that

- the mast (2) can pivot beyond the vertical - and can be tilted towards the windward side.

4. Mast system for sailboats according to one of claims 1 - 3, characterized in that the mast base (8) can be pivoted through a small angle about the transverse axis of the boat.

5. Mast system for sailing boats with at least one boat hull (4) and at least one mast (2), which is fixed by means of a mast base (8) attached to the boat hull, characterized in that two masts (2, 2') are provided, which are arranged symmetrically to the central plane (3) of the boat running through the longitudinal axis (9) and their mast tips (16, 16') to the central plane (3) of the boat are inclined towards.

6. Mast system for sailing boats according to claim 5, characterized in that the mast feet (8, 8 ') of the two masts (2, 2') can each be pivoted about an axis parallel to the longitudinal axis (9) of the boat, and when sailing against the wind or with clear wind the leeward mast (2 or 2'), - regardless of the heeling of the boat,

- each can be aligned approximately in the vertical direction.

7. Mast system for sailboats according to claim 5 or 6, characterized in that

- the leeward mast (2 or 2') can pivot beyond the vertical and can be tilted towards the windward side.

8. Mast system for sailing boats according to one of claims 5 - 7, characterized in that when sailing with aft wind both masts (2, 2 ') are equipped with sails (11, 11'), - and preferably between both masts (2, 2') at least one further sail (11") is provided.

9. Mast system for sailing boats with at least one boat hull and at least one mast, which is fixed by means of a mast foot attached to the boat hull, characterized in that two masts are provided which are arranged symmetrically to the central plane of the boat running through the longitudinal axis and in the area of Mast tips have a rigid joint

Sail (= wing) is pivotably attached.

10. Mast system according to claim 9, characterized in that

- Each of the rigid sails can be aligned with its main plane approximately in the horizontal and vertical planes.

11. Use of the mast system according to claim 9 or 10, characterized in that the leeward-side sail is aligned approximately horizontally and the windward-side sail is aligned approximately vertically.

12. Use of the mast system according to one of the preceding claims, characterized in that it is used on a boat with a hull, - preferably on a yacht or a dinghy.

13. Use of the mast system according to one of the preceding claims, characterized in that it is on a boat with several hulls,

- preferably used in a catamaran or trimaran.

14. Mast system for sailing boats according to one of claims 1 - 13, characterized in that the two masts are each fixed to the boat hulls that are spatially furthest apart.

15. Mast system for sailing boats according to one of claims 1 - 14, characterized in that preferably extendable floating bodies are provided on both sides of the hull(s), the extension direction pointing perpendicular to said longitudinal axis.

16. Mast system for sailboats according to one of the preceding claims, characterized in that the mast system is used for sand or ice sailing boats.