Field of application The present invention relates to an inflatable boat for sport and leisure, particularly suitable to be used by inexperienced people or people having a reduced functionality of the limbs.

Prior art There are many known boats for sport and leisure which essentially consist of a hull made from a light, rigid or semirigid material, such as reinforced resin or aluminum, and are possibly provided with means for stabilization and directional control, such as fins and rudders.

In order to reduce the weight and bulkiness of the hull, as well as the risks of bumps and contusions for the users, collapsible hulls have been developed, essentially of the inflatable type, which consist of an inflatable mattress or raft for one or more persons, either in the sitting or lying position.

The propulsion of these boats may be provided by an internal combustion engine or by an electric motor which has the advantage of a high environmental compatibility but is unfortunately still fairly complicated and expensive.

As an alternative, a conventional sail may be used for these boats, which sail can be hoisted on a mast removably fixed to the hull.

However, these sail structures do not completely eliminate the risks for the users, mainly due to the presence of a mast, increase the overall weight of the boat and reduce its ease of handling, particularly for people with reduced functionality of the limbs. Moreover, these boats have a certain structural complexity which increases their manufacturing and maintenance costs.

Summary of the invention The main object of the present invention is to overcome the above-mentioned drawbacks by providing a boat with an extremely simple and light structure, so as to be easily transported and handled even by people with reduced functionality of the limbs.

A further object is to provide a sail-propelled boat with a high efficiency despite the small sail area.

Another object is to design a boat which is safe, comfortable, cheap and absolutely ecological.

Not a least object is to devise a boat structure which can be obtained through

extremely simple operations and processes starting from materials easily found on the market.

These and other objects which will be better defined further on are achieved by an inflatable boat for sport and leisure including a hull, a sail and means for the control and directional stability, characterized in that both said hull and said sail are inflatable self-supporting structures made from a plastic material.

Thanks to this completely inflatable structure, the boat according to the present invention has a low weight which provides a great ease of handling even for people with reduced functionality of the limbs. Furthermore, the deflated boat has a very small bulkiness which makes easier its transportation on normal cars without trailer.

Preferably, the sail-forming member includes a first outer envelope of plastic material with an inflation valve. In the inflated state, the envelope takes the shape of a geometric solid extending in a main plane and having a substantially constant cross-section consisting of an airfoil which defines both the sail area and its supporting mast.

Brief description of the drawings The invention will now be described in greater detail with specific reference to a preferred but not exclusive embodiment of a structure of a collapsible boat for sport and leisure, illustrated for exemplificative and non-limiting purposes, with the aid of the enclosed drawings wherein:

FIGURE 1 shows a global perspective view of the boat according to the invention,

FIGURE 2 shows a lateral view of the boat of fig.1; FIGURE 3 shows a top plan view of the boat of fig.1 ;

FIGURE 4 shows a view of the boat of fig.2 sectioned along line IV-IN; FIGURE 5 shows a view of the boat of fig.3 sectioned along line N-N.

Description of a preferred embodiment With reference to the cited drawings, a boat according to the invention, globally indicated by reference numeral 1, essentially includes a hull 2 on which a sail 3 is mounted.

According to the invention, both hull 2 and sail 3 consist of inflatable and self-supporting elements.

In particular, the hull member 2 essentially consists of an inflatable mattress formed by a hermetically sealed outer envelope 4 of flexible plastic material, e.g. reinforced PVC, which in the inflated state has an almost rectangular plan shape

with rounded edges and a longitudinal middle axis L.

A plurality of longitudinal reinforcing membranes 5, of a flexible but substantially inextensible material, extending approximately along the whole length of the hull so as to define inner adjacent and communicating chambers 6 are secured within envelope 4, e.g. by heat sealing. Preferably, membranes 5 are inclined with respect to the plane of hull member 2 and converge, from opposite sides with respect to the middle axis L, towards an axis parallel thereto and located above hull 2 so as to provide a higher strength in the vertical direction.

A connector 7 including a safety valve, not shown in the drawings, is fitted on the outer envelope 4 to allow the introduction of low pressure air through conventional manual or mechanical pumping means.

The sail member 3, in the inflated state, is an elongated geometrical solid having an almost rectangular plan shape extending in a main plane P and a substantially constant cross-section along its longitudinal extension. In particular, the cross-section of member 3 is shaped as an airfoil, e.g. of the

NACA type, such as to provide a high aerodynamic efficiency at low speeds of the apparent wind and a high sail lift.

To this purpose, member 3 is made up of a hermetically sealed outer envelope 8 internally stiffened by a plurality of reinforcing membranes 9, of a flexible but substantially inextensible material, extending approximately along the whole length of the member so as to define therein a series of adjacent and communicating chambers 10. Thanks to this structure, the inflatable member 3 has a very high flexural and torsional rigidity which makes it self-supporting thus avoiding the use of a mast or an external supporting member. In a preferred embodiment, the inner space of the sail member 3 is divided by a transverse dividing wall 11, located about at mid-height, into an upper portion 3' and a lower portion 3" provided with respective inflation connectors 12, 13 with safety valves not shown in the drawings. Thanks to this configuration, it is possible to inflate selectively both portions 3', 3" or only the lower portion 3", while folding thereon the upper portion 3', so as to change the sail area and therefore the propulsive force of the boat.

Conveniently, at the lower end of envelope 8 there is secured a plate 14 of a rigid or semirigid material from which a hub 15 extends out of member 3 along an axis H passing through the main geometrical plane P and the pressure center of the airfoil.

After inflating chambers 3', 3" the outer surface of member 3 will take a

somewhat corrugated shape due to the tension produced at the membranes 9. In order to reduce the surface unevenness of member 3, it is possible to cover the latter with an external sheath 8' of a flexible and elastically yielding material.

In the hull member 2, along the longitudinal middle axis L in a position slightly forward of the center of gravity of the hull, there is inserted a sleeve 16 of a fairly rigid material having a central bore 17 with an axis which is substantially vertical or perpendicular to the longitudinal axis L. The inner diameter of bore 17 is slightly greater than the outer diameter of hub 15 so as to rotatably receive the latter and to allow the orientation of sail 3 by the user. The rotation of member 3 can be carried out by acting on side handles 18 secured to the outer envelope 8 or on other handling means integral with the latter or with hub 15.

Possibly, the hull may be provided with a mobile or fixed stabilizing fin 19 and with a rudder 20 controlled by a sitting or lying user through a closed-loop cable 21 running along the periphery of hull 2. It is possible that fin 19 be mobile so as to act as a rudder while rudder 20 is fixed so as to stabilize the hull.

In use, hull 2 and sail 3 are inflated first, possibly covering the latter with sheath 8'. Then, sail 3 is mounted on hull 2 by introducing hub 15 in the inner bore 17 of sleeve 16 integral with the hull. It is clear from what said above that the inflatable boat according to the invention achieves all the intended objects, and in particular worth to be noted are its manufacturing simplicity and its extremely low weight suitable to make its handling easier even for people with limited functionality of the limbs.

The boat according to the invention is susceptible of several changes and modifications, all within the inventive concept resulting from the annexed claims. Furthermore, all the details may be replaced by other technically equivalent details which are all intended to be equally protected.