DESCRIPTION

The present invention relates to a goniometric rule for defining points of sail as an aid to sailing. For the purposes of the present invention, defined as "points of sail" are the different modes of advance that a sailing vessel can assume with respect to the direction of the wind.

On the basis of Bernoulli's principle, propulsion in sailing boats is produced, in a way similar to the aerodynamic lift on the wing of an aircraft, by the difference of pressure generated by the wind on the two "faces" of the sail. The different direction of the wind with respect to the longitudinal axis of the watercraft forces skippers to modify the adjustment of the sails in order to exploit the thrust of the wind on the sails in the best possible way.

To indicate the wind direction with respect to the longitudinal axis of the boat there has been developed a conventional system that divides the angle between bow and stern of the watercraft (corresponding to 180°) into 16 parts referred to as "points ", each corresponding to 11°15' . Wind direction is conventionally indicated in terms of points, which provide an immediately understandable indication to the skipper of the boat and to the sailors of the adjustments to be made to the sails. Conventionally sailing against the wind or windward is also defined as "sailing close hauled" , which identifies points of sail where the wind comes from between six and four points from the bow. It is moreover possible to distinguish said mode of sailing between "close haul" (40-45 degrees between the longitudinal axis of the boat and the wind direction) and "close reach" (45-55 degrees between the longitudinal axis of the boat and the wind direction) , but how closely a boat can sail into the wind depends upon the boat's design, sail shape and trim, the sea state, and the wind speed. Defined as "beam reach" (also referred to as "amidship") is sailing with the wind perpendicular to the longitudinal axis of the watercraft (i.e., at 90 degrees) . Sailing off the wind can be divided into "sailing downwind" , when the wind blows sideways on to the watercraft, with an angle with respect thereto that can range from four points from the stern (also referred to as "broad reach") to six points from the stern, up to "beam reach", where the wind blows in a direction perpendicular to the longitudinal axis of the watercraft .

Running comprises points of sail referred to as "quartering run" for the wind coming from between two and four points from the stern, and the point of sail referred to as "running before the wind" , for the wind direction parallel to the longitudinal plane of the watercraft. In this point of sail, the watercraft proceeds in the same (or almost the same) direction as the wind. Sailing directly before the wind is extremely dangerous in so far as a rapid change in wind direction can cause the mainsail to gybe, i.e., swing from one side of the vessel to the other, without any prior warning.

Points of sail may also be classified as: "beating" or "tacking" , where the watercraft is proceeding upwind; and "bearing away", where the watercraft is pushed along by the wind.

The above classification is the one normally used since the conditions of navigation, the type of sails, and the behaviour of the watercraft with respect to the wind and to the wave motion vary in a determining way in the two conditions referred to above .

When the watercraft has its head in the eye of the wind, i.e., the axis of the watercraft is facing directly into the wind, it is ungovernable or very difficult to govern, the sails do not take the wind, and the boat does not make any headway. This is a "no-go" or "no-sail zone" and is defined as "in irons" . It cannot strictly be defined as a point of sail; however, the technique of heading into the wind is frequently used in regattas to stop the sailboat .

"Velocity Made Good" (VMG) is the true speed or velocity of approach to a given point when it is impossible for the sailing vessel to follow a direct course to reach said point. Typically, a sailboat that has to proceed upwind to reach its target will lengthen its path, and the VMG indicates the true velocity of approach to that point . This applies also when the craft is on a broad reach towards the downwind buoy; in this case, the VMG represents how fast the craft can gain the downwind buoy. As illustrated in Figure 2, the true velocity of the sailcraft (a windsurf in this case) is the resultant of two components: the VMG and the velocity lost, i.e., the component perpendicular to the wind. The latter helps the sailcraft to beat the course upwind, but does not bring it closer to the upwind buoy.

A good way to understand what is "Velocity Made Good" is to imagine a motor boat and a sailboat that traverse the upwind leg between the starting line of a regatta and the upwind buoy. The motor boat follows the straight line between the start and the buoy whilst the sailboat has to make a number of tacks to gain the buoy. If the motor boat adjusts its speed so that it will always be at the same point as the sailboat with respect to the regatta field (so as to be able to reach the buoy at the same time as the sailboat) , the speed of the motor boat would correspond to the VMG of the sailboat . Optimizing the VMG is far more important that than simply going fast. When proceeding windward, by- bearing off, the boat will tend to accelerate, and by luffing as much as possible, the bow will approach the buoy more closely but this will entail a loss of speed. Understanding in what condition pointing high, that is plying to windward, or getting the boat to advance faster counts more is fundamental in the tactics of any regatta. VMG is the critical factor for any regatta with a windward/leeward or triangle course, whereas pure speed is important only to the extent that it affects VMG.

For instance, on a beam reach the velocity is maximum but, since the craft will not approach the upwind buoy, the VMG will tend to zero; likewise, by directing the bow straight into the eye of the wind, the boat will not move at all, and hence the VMG will again be zero. Somewhere between the beam reach and head into the wind there is an angle that optimizes the craft's speed as it proceeds upwind, and identifying this optimal angle is one of the tasks of the crew. It is no simple task because it depends to a large extent upon the equipment, the weather conditions, the weight of the boat, and the style of marine operation.

Sailboats, above all ones participating in regattas, are equipped with a vast range of sails of different shapes, each of which is optimal for a specific point of sail .

By way of example, the sail called "genoa" or "Genoa jib" or "jenny" is optimal for close haul and close reach; the sail called "gennaker" is optimal from beam reach to broad reach; and the sail called "spinnaker" is optimal from broad reach to running. It is the task of the skipper of the watercraft to decide the sail to be hoisted that is best suited to guarantee VMG.

In the case of sailing, whether for pleasure or for competition regatta, the changes of direction of the watercraft are frequent . In the case of change in direction, the watercraft assumes a different point of sail with respect to the wind and the skipper of the watercraft has to decide, before starting change of direction, which sail will optimize propulsion. This decision is usually taken by calculating mentally wind direction, direction of the craft, and sail efficiency. These calculations are in themselves simple if not made in a rush, but may be complex and lead to error if performed in navigating conditions that do not guarantee sufficient calm. The evaluation of the new point of sail that the watercraft will assume after changing direction can be facilitated by sophisticated and costly electronic systems that not everybody has on board. The purpose of the present invention is to provide a manual tool that will be extremely easy to use even in difficult situations, easy to carry, and will provide indications on what will be the point of sail of the watercraft with respect to the wind according to the direction that the watercraft is following or is about to follow. With a variant to the invention, it may also indicate visually what will be the best sail to use to achieve maximum VMG. With yet a further variant, it may indicate the polar chart of the sails in order to obtain an immediate indication not only of the best sail to use, but also of what will actually be its level of efficiency. The present invention relates to a goniometric rule for defining points of sail provided as an aid to sailing, which has the characteristics of the main

Claim 1.

Further characteristics of the rule are contained in the dependent claims .

One embodiment of the present invention is set forth in what follows with reference to the attached plates of drawings, wherein:

Figure 1 shows the different positions of a sailing vessel with respect the wind direction;

Figure 2 is an explanatory chart illustrating the optimal speed or velocity of approach (velocity made good - VMG) ;

Figure 3 is an axonometric view of the rule in its simplest example of embodiment;

Figure 4 is an exploded view of the rule illustrated in Figure 3 ;

Figure 5 is an axonometric view of the rule, with the indications of the sectors of efficiency of the sails;

Figure 6 is an exploded view of the rule illustrated in Figure 5; Figure 7 is an axonometric view of the rule, with the addition of the element 12 ;

Figure 8 is an exploded view of the rule illustrated in Figure 7 ;

Figure 9 is an axonometric view of the rule, with the indication of the polar chart 6;

Figure 10 is an exploded view of the rule illustrated in Figure 9;

Figure 11 is an axonometric view of the rule, represented in which is the pointer 10 instead of the indicator means 7 ;

Figure 12 is an exploded view of the rule illustrated in Figure 11;

Figure 13 is a schematic illustration of the rule inserted in a watch;

Figures 14, 15, 16, 17, 18 and 19 are various non- exhaustive embodiments, provided purely by way of example, which can carry the various elements 2, 3 and 12.

For the purposes of the present invention, it is understood that the polar chart for a given sail will show what will be the best velocity of the craft in relation to the true wind and the angle formed by the boat therewith.

With reference to the above figures, the rule 1 according to the present invention comprises, in a first example of embodiment, which is not exhaustive in so far as the embodiments may be very different albeit achieving the same purpose, two graduated concentric elements or disks 2 and 3 fixed on top of one another, with the top one 3 having a diameter smaller than the underlying one 2.

The top one 3 can be turned with respect to the underlying one 2, or else, the underlying one 2 can be turned with respect to the top one 3. The larger underlying disk 2, in the part that extends beyond the smaller top one 3 is graduated, preferably, but not necessarily, over 360 degrees, but also in sectors. The smaller top disk 3 is graduated with respect to a longitudinal axis thereof, preferably, but not necessarily, over 180 degrees to the right and 180 degrees to the left. The longitudinal axis of the top disk 3 will coincide on one side with zero degrees to the right and zero degrees to the left and on the other side 180 degrees to the right and 180 degrees to the left. In one variant, there may be indicated by colours or other means of indication the sectors 5 of effectiveness of the various sails available, the latter being formed in the example of embodiment by a division of an annulus with different patterns or colours or simply coloured lines indicating the sector of efficiency of each specific sail; to the right and to the left of the zero will be indicated a sector in which the watercraft will receive no sailing propulsion in so far as it is facing directly into the wind. Yet again, in a further variant embodiment, there may be indicated the polar chart of the sails available 6, thus obtaining a very precise indication on the best sails to use. The rule 1 moreover comprises indicator means 7 (one, two, or more) on the bottom element of larger diameter 2 that the skipper of the watercraft can displace, insert, or engage (according to the type of indicator means 7 of the rule and the mode of insertion envisaged therefor) at the point of the bottom element 2 that indicates the degrees of the course that is being followed or will be followed. It will be the ideal alignment 8 of these indicator means 7 with the centre of the disk 9 that will indicate on the graduated scale 20 of the top element 3 what will be the point of sail that the watercraft has assumed or will assume. The rule may ^¬ be made of any material and with shapes that may even not be round and with the indicator means 7 that could be pointers 10 passing through the centre 9, wires passing through the centre, or with a further element set on top of the two elements 2, 3, which is provided with slits windows.

The rule 1, in the example of embodiment thereof, which is not exhaustive in so far as it may be made with various shapes, sizes, and materials, functions as described in what follows. a) Once the direction of the wind in degrees has been identified, the zero point 11 of the graduated scale 20 of the small element 3 is made to collimate with the degrees 2C of the wind direction on the disk 2. b) The indicator means 7 is positioned on the degrees 2C on the element 2 for the direction to be monitored. c) The ideal line 8 joining the centre 9 of the rule to the indicator means 7 will indicate on the disk 3 the degrees of wind direction with respect to the hull, with the bow of the watercraft oriented in the direction monitored; hence the point of sail is obtained therefrom.

In a variant illustrated in Figures 5 and 9 with indications of the sectors of effectiveness 5 of the sails or else with the polar chart 6 indicated on the disk 3, we shall have also an immediate indication of the type of sail that it is preferable to use. With the example of embodiment with two disks, i.e., the smaller disk 3 on top and the larger one 2 underneath, the indication of the point of sail that we shall obtain will be the correct one, but the wind direction indicated will be reversed: if the ideal straight line 8 joining the indicator means 7 and the centre 9 are in the left-hand sector of the disk 3, the real direction of the wind that we shall obtain in the point of sail monitored will be to the right, and vice versa. This can be obviated, possibly, by reversing from a clockwise direction to a counterclockwise direction the progression of the degrees 2C of the element 2; i.e., with the zero set to North, for example, we shall have 90 degrees in the example of embodiment set forth here to the left instead of to the right. In this way, the indication of the point of sail that we shall have will be correct, with the direction of the wind indicated properly.

A more complex embodiment of the rule 1 (illustrated in Figure 8) envisages three rotatable elements: a large one 2, a small top one 3, and another small bottom one 12, the small disks 3 and 12 being fixed to one another so that by turning them we shall have the reading of wind direction on the top disk 3 reversed, but by reversing the rule, instead, we shall be able to read the correct wind direction on the visible face of the disk 12A.

Furthermore, by keeping the indicator means 7 for indicating the course of the craft on the larger stationary element 2, in the event of variation in wind direction with respect to the one fixed, it will be sufficient to turn the disk 3 so as to fix the zero point 11 of the small element 3 on the degrees 2C indicated on the disk 2 of the new wind direction to obtain an immediate and precise reading of the new point of sail with respect to the boat . The invention in a more advanced embodiment (illustrated in Figure 13) can be easily inserted into the case of a watch, where the element 3 can form the quadrant 15 of the watch and the element 2 can form the outer ring 16 of the watch, the indicator means 10 can be the pointer 17, or else one of the fingers indicating either the hour, the minutes, or the seconds 18. The quadrant 15 can bear the indication of the sectors of the sails 5, or else the polar chart 6, or else be without the sector of the sails 5 and without the polar chart. To regulate the device according to the invention 14 it is indifferent whether the outer ring 16 or the inner quadrant 15 is turned. The mechanisms for moving the outer ring 16 or the inner quadrant 15, or the indicator means 17, or the fingers 18 to obtain reading of the point of sail are mechanisms that are already known.

The element 14 can have any shape and size whatsoever, as well as having straps 19 for being fixed to the wrist or be without straps if it is a portable object.