ROTABLE AXIS TO WHICH THE MAST, CENTREBOARD, WINCHES ARE CONNECTED
Technical Field
This invention relates to sailing equipment. More specifically, it relates to a device able to facilitate manoeuvring, allowing the mast to be disengaged from the bottom of the watercraft.
Background Art
The rigidity of the mast unit - i.e. the mast, bottom, and keel assembly - hinders manoeuvrability of sailing vessels using the sails only.
The problem is particularly noticeable when sailing close to the wind to the extent that there is a critical angle (direction of the watercraft/wind direction) below which it is impossible to proceed.
This invention aims to resolve the aforementioned problem improving the manoeuvrability of watercraft fitted with sails such as sailing boats and catamarans. Objects and Brief Description of the Invention
It is an object of this invention to provide a device, hereinafter called the "polar mechanical axis", consisting of a free-to-rotate spar to which the mast, centreboard, winches, rope stoppers, and any other rings for fastening the rigging are solidly connected. Description of the Drawings
Fig. 1 shows the polar mechanical axis in accordance with the invention
Fig. 2 shows a top view of a watercraft fitted with the polar mechanical axis in accordance with the invention.
Fig. 3 shows a side view of the watercraft depicted in Fig. 2 with the relating sails. Fig. 4 (a and b) shows two detail views of the device in accordance with the invention.
Fig. 5 shows the possible mast movements using the device in accordance with the invention.
Detailed Description of the Invention Figure 1 shows the polar mechanical axis (10) in accordance with the invention.
Said device consists of a spar (11 ) that is free to rotate and is solidly connected with the mast (15).
The spar (11 ) rotates thanks to ball bearings (12), which are housed inside at least two brackets (13) for fastening the spar (11 ) to the bottom (14) of the watercraft. Ideally, the different ball bearings feature retainers to prevent them from sliding along the spar (11 ). Along said spar (11 ), devices are fitted and solidly connected for adjusting the sails; these devices may include two or more winches (16), one or more rope stoppers (17), and one or more rings (for example, downhaul) (18). All said devices comprise a hollow cylindrical coupling (19), which is integral and perforated (20), for fastening to the spar (11 ) with appropriate mechanical fastening means (for example, pins or screws and bolts). When said means are inserted into the holes (20), they fit into the corresponding holes in the spar (11 ); obviously, the spar (11 ) has several holes along its length in order to fit the different devices according to sail manoeuvring needs. The rope stopper (17) can consist of a raised surface (17'), connected with the coupling (19) by means of an arm (19'), to which are fastened the actual rope stoppers (17") required for manoeuvring and the rings (17"') for sliding the ropes of the boom.
The winches can be arranged similarly, i.e. on a raised surface (16') connected with the relating coupling by means of an arm (19'). The centre of the mast (15) is solidly joined with the spar (11 ); the bottom of said mast forms a single body with the centreboard (21 ) that ends in a bulb (22). In a particular version of the invention, the bottom of the mast, where it is crossed by the spar (11 ), comprises another articulated joint for bending the mast on the port side or on the starboard side; thus, this joint allows the mast to be positioned differently in relation to the centreboard (and, hence, the bulb).
In this version of the invention, the mast (15) is solidly connected with the spar (11 ); the centreboard (21 ) forks at the bottom of the mast (15) and there are two circular flanges housing two ball bearings (23) in the central hole of which the spar (11 ) passes; while the mast (15) slots into the fork (see Figure 4b). At the top of the centreboard (21 ), and solidly connected with it, there is a crown (24) that is perforated to allow the passage of the spar (11 ). Said crown (24) engages with appropriate reduction gears (25) positioned at the bottom of the
mast (15) (see Figure 4a).
The crank (26) can be used to move the centreboard (and, thus, the bulb) in relation to the mast even when the centreboard and the bulb are quite heavy
(thanks to the reduction gears, 25). Furthermore, in another version of the invention, the mast (15) comprises a hinge positioned, preferably, between the crank (26) and the attachment of the shrouds
(27). Said hinge may consist of, for example, a bush with pivot pin (28) and allows the mast to tilt towards the stern or towards the bow, manoeuvring with the relating winches positioned on the spar (11 ). The spar and mast assembly is attached to the bottom by means of brackets (13) that are solidly connected with the floors.
In the midpoint, where the mast and the centreboard are found, the bottom features a pit (29), preferably rectangular, that allows the bottom of the aforementioned assembly to be immerged in water. Ideally, said pit has four bulwarks (30) to prevent any seawater from entering.
Each of the two opposite bulwarks in the stern / bow direction will obviously have a hole, with the relating ball bearing, to allow the passage of the spar (1 1 ); furthermore, said holes may be equipped with a stuffing box (31 ) to guarantee watertightness. In a particular version of the invention, the mast (15) and the centreboard (21 ) - with the relating bulb (22) - are not positioned coaxially as shown in Fig. 1 and, thus, do not form a single unit as described above.
In this version, the mast (15) is solidly connected with the polar mechanical axis
(10) in a position closer to the bow of the watercraft; while the centreboard (21 ), with the relating bulb (22), is connected with the polar mechanical axis at the barycentre of the watercraft. Obviously, in this case, the pit (29) is found in the barycentre.
Preferably, there are four brackets (13): two positioned at the end of the stern and bow of the bottom, respectively, and the other two immediately outside the bulwarks (30).
Considering the described polar mechanical axis, the shroud system must be modified. Particularly, the stern backstay and the bow stay are fastened to the
rings (31 ) placed at the two ends of the spar (11 ).
The bottom of the mast, i.e. the part included between the spar (11 ) and the first crosstree (32), is made of material able to offer the maximum resistance to stress
(for example, steel), while the top is made of light materials (for example, carbon fibre).
If preferred, the lighter top part can be bayonet fitted into the bottom resistant part and secured with appropriate fastening means (for example, screws and bolts).
The shrouds at the top of the mast will be positioned and fastened as usual; however, they are not attached at the bottom to the deck as usual but to the mast (15) in the section (27) included between the first crosstree and the reduction gears (25).
From the aforesaid and as shown in Figure 5, the above described device - particularly, the mast, sails, centreboard, winches (i.e. the entire motor structure of the boat) - forms a single unit that works independently from the bottom, whish serves as a float able to support the watercraft with the relating movement over the surface of the water. Obviously, if preferred, the bottom (14) can be fitted with appropriate outside bulwarks (30').
Figure 3 shows the sails of a watercraft fitted with a polar mechanical axis in accordance with the invention. As the figure shows, it is possible to use a jib (33) similar to a spanker - with boom (35) down - and a small riding boom (34) at the height of the last crosstree that is kept perpendicular to the mast by two horizontal ties (that are tied to the ends of the crosstree) and by a vertical tie that attaches the tip of the small riding boom to the mast. This small riding boom (34) pushes forward the stay (36), allowing the jib to operate similarly to a spanker placed before the mast.
To place the small riding boom (34) before, tighten a rope from the first crosstree to the ring of the downhaul of the riding boom (18) in order to secure the mast; then, the loosen the stay to insert the small riding boom in the last crosstree; and, finally, tighten the staysail and the remove the safety rope.
The advantages of this invention are obvious.
Firstly, being able to tilt the mast means that the bottom does not tilt and, thus,
remains perfectly parallel to the surface of the water and does not loose speed. It is also possible to fit the watercraft with a flat bottom (like on windsurfs): this creates a gliding effect on the water that further increases speed. Finally, it is not longer necessary to make the watercraft with a narrow bow (as in the case of known watercraft); thus, the bow can be rounded making available a space that can be used, for example, to construct a deckhouse or other type of shelter - which are items particularly appreciated on pleasure boats.