Technical Field

The present invention relates to an apparatus in sailing boats of the kind disclosed in the preamble to claim 1.

Background Art

Many different attempts have been made to improve the sailing properties of sailing boats by optimising the coaction between the design of mast, mainsail and jib. It has been proposed, inter alia, to form the mast as a rotatable airfoil, whereas less interest has been paid to the design an placing of the mainsail.

Disclosure of Invention One object of the present invention is to improve the properties of sailing boats with reference to the sailing conditions. This object is achieved by the apparatus in accordance with the invention having been given the distinguishing features disclosed in the characterizing portions of the claims.

Description of Figures

Figure 1 is a schematic, partly sectioned side view of a sailing boat including the apparatus in accordance with the invention. Figure 2 is a schematic partially sectioned view seen from above of the apparatus according to Figure 1 , and

Figure 3 is a schematic partial view to a larger scale of the apparatus according to Figure 2, seen from above.

Preferred Embodiment

In Figure 1 the step of a sailing boat is denoted by 1 and the deck thereof by 2, to which there are respectively mounted fixings 1a and 2a for the lower part 3a of a mast 3. The mast 3 is rotatably mounted in these fixings. The mast is hollow and has an aerodynamic shape

with a teardrop exterior cross section which decreases upwards. Inside the mast 3 there are unillustrated means for rolling up and feeding out a mainsail 4 through a slit 3b along the aft edge of the mast. The leech 4a of the mainsail 4 is connected via the outhaul 6a on a boom 6 to a mainsheet 5, which is fastened to the boat deck 2. The boom is of the wishbone type, i.e. it is bifurcated and curves round the sail. At its forepart the boom 6 is coupled by a vertical rotation shaft 7 to a support means 8, which will be described in detail below. The boom 6 and support means 8 are normally prevented from mutual turning by a setting means comprising a screw 9 threaded into a nut on the boom part 6a and a sheave attached to the other end of the screw, a line 11 running in the groove on the sheave 10. Sheaves 12 and 13 on the support means 8 and sheaves 14 and 15 inside the mast guide the line 11 inside the mast and further out at the mast portion 3a.

A shaft 16 extending along a substantial part of the mast 3, is rotatably mounted inside it, stirrups 17, 18, 19 and 20, which form the support means 8, are fixed to the shaft 16 at predetermined spacings, unillustrated horizontal slots being made in the forepart of the mast at the places where the stirrups project into the mast to enable relative turning between mast and stirrups. As will be seen in Figure 2, each stirrup 17 - 20 has a triangular shape, with two adjacent legs somewhat convex and with radii of curvature corresponding to a desired curvature of a jib 21 , which is inserted in and surrounded by the stirrups 17 - 20. The luff 21a of the jib 21 is inserted in a forestay 27 in the corner between the legs of the triangles, the luff being kept somewhat stretched by a cable or the like inserted in its hem, and connected to halyard 22 and pulley block 22a. The stirrup 20 is provided with a holder 23 thrusting into the mast 3, on which a sheave 24 is

rotatably mounted. The sheave 24 has a threaded centre hole. A curved screw 25 is fastened inside the mast 3 and engages with the centre hole of the sheave 24. The sheave 24 is arranged for rotation by a line 26 which runs inside the mast and is available at its lower part 3a. When the sheave is rotated, it is displaced along the screw 25, the angle between the mast 3 and support means 8 thus being changed, resulting in that the angle between the mast and boom 6 is also changed, since the boom is connected by the stirrups with the aid of the means 6a, 9, 10.

During tacking, when the mainsail 4 and thus the boom 6 are taken from port to starboard or vice versa, this movement only being restricted by the mainsheet 5, the support means 8 is turned in the same direction around the axis of the shaft 16, the jib 21 automatically being set at the correct angle to, and at the correct distance from the mast 3 into supporting engagement against one of the two legs of the stirrups 17 - 20 directed substantially in the mid-line direction of the boat. Due to this engagement it is not necessary to tension the halyard 22 particularly severely.

If there is a need of altering the last mentioned angular position between mast, mainsail and jib, and the size of the gap between them, the setting means 6a, 9, 10 is actuated by the line 11.

When the boom 6 and support means 8 are swung, the mast 3 is also turned round the axis about which the lower part 3a of the mast is situated. If there is a need to change the angle of the mast 3 to the wind, or relative the boom 6 and support means 8, the setting means 23 - 25 is actuated by the line 26. The resistance of the mast to the air is thus decreased simultaneously as the effective sail area is increased. Even though only one embodiment of the invention has been shown on the drawings and described above, it

will be understood that the invention is not limited to this embodiment, but only by the disclosures in the claims.