In order to allow direct underwater viewing from boats in particular of a simple and low-cost type such as those intended for use by divers or for recreational purposes, a part of the bottom of the boat has a portion made of transparent material; these boats are all of the type which are propelled by means of oars or an engine and moreover, as a result of their traditional form and structure, pose some problems with regard to transportation and storage thereof.

Also, devices consisting of a cylindrical or frusto- conical body, on the bottom of which a transparent sheet of glass or plastic is inserted, are already known.

These devices may also be used while merely standing on- board a boat.

Some of the drawbacks mentioned above have already been solved by a raft forming the subject of British patent application No. GB 2,188,881, said raft being designed to support a person laying flat in a supine position and

being propelled by the same person via the movement of his/her legs. The raft is provided at the bows with a well having on its bottom a small window which allows the person to look into the water from the supine position. The raft is made as one piece from reinforced resin or styrene by means of vacuum-injection and/or moulding. The raft described above briefly is difficult to transport, cannot be connected to other rafts and is not suitable for film shooting or photography since the well is completely open and the water is able to enter inside it, making both viewing of the sea bottom and installation of filming or photographic equipment of the traditional type impossible.

There are no protective, i.e. water-tight, compartments for holding objects or equipment.

The same drawbacks mentioned above are also present in the rafts described in US patents 4,925,417 and US 5,447,459.

The object of the present invention is therefore that of providing a craft which, together with the fact of allowing underwater viewing and of being moved by the muscular power of a person, allows the use of different types of filming and/or viewing systems which are interchangeable in accordance with requirements.

Another object of the craft forming the subject of the

present invention is that of having a limited size and weight in order to facilitate as far as possible storage and transportation.

These and other objects are all achieved by the muscle- propelled craft designed to allow underwater viewing according to the present invention, of the type comprising two side bodies which have a prismatic shape and are made of varying non-sinkable material and which are connected together in their bottom part by a bottom- piece occupying substantially one half of the length of the said craft and being joined, along the longitudinal axis thereof, to the upper part thereof by means of a transparent inclined surface; a transparent bottom-piece positioned in the bottom part of the craft in the remaining half thereof and at the same level as the said bottom-piece; and a transparent front portion of the front part of the craft, this portion forming the continuation of the transparent bottom-piece, which is characterized in that it is divided up transversely into two halves kept in the position for use by a plurality of fastening means, said two halves being connected by a hinge device designed to allow folding-up or separation of said two halves for the purposes of easy transportation of the craft itself. A further important characteristic feature consists in the fact that the

bows zone has formed in it through-holes inside which interchangeable containers with a transparent bottom are inserted.

These and other characteristic features will emerge more clearly from the following description of two preferred embodiments illustrated, purely by way of a non-limiting example of embodiment, in the accompanying illustrative drawings, in which: - Figure 1 shows a top axonometric view of the craft; - Figure 2 shows a bottom axonometric view of the craft; - Figure 3 shows a longitudinal cross-sectional view of the craft; - Figures 4 and 5 show two different axonometric views of the folding version of the craft in the folded position for transportation; - Figure 6 shows a perspective view of a second embodiment of the craft; - Figure 7 shows a plan view of the craft according to Figure 6; - Figure 8 shows the craft sectioned along the line VI- VI of Figure 6; - Figure 9 shows a sectional view of a detail of the craft.

With reference to Figures 1) to 5), the first embodiment comprises two side bodies 1 which have a prismatic

shape, are made of varying material and are filled preferably with polyurethane foam to ensure that the craft is unsinkable. The two side bodies 1 are connected together at the bottom by a bottom-piece 2 and by a transparent bottom-piece 4; the line separating the said two bottom-pieces coincides with the transverse division of the craft into two halves and, astride this dividing line, there is located a hinge device 6 designed to allow folding-up of the two halves of the craft onto one another. Fastening means 11 keep the two halves of the craft in a stable position during use thereof. The two side bodies 1 are moreover connected together at the top by a cross-piece 9 positioned above the transparent bottom-piece 4 and, at the front, by a transparent portion 5 having the same configuration as the remaining front part of the craft.

The bottom-piece 2 is connected to the upper edge of the two side bodies by a transparent inclined surface 3 designed to support either the chest or the back of the person using the craft; in the case where he/she is supported by the chest, the person has the possibility of underwater viewing through the said transparent inclined surface and the transparent bottom-piece 4 as well as through the transparent front portion 5, these elements forming a- front chamber 10 defined laterally by

the two side bodies 1.

According to a possible variation of embodiment, the front chamber 10 may be closed at the top by a transparent flap, not shown, for preventing water entering into and filling the chamber itself in the event of the craft capsizing.

The craft in fact may advantageously be turned over so as to act as a sun-bathing or diving platform.

A small pipe 12 positioned in the bottom-piece 2 and connected to the front chamber 10 acts as a drain for any water which may have entered into the front chamber; said pipe is provided with a one-way valve which allows only drainage of the water.

The transparent inclined surface 3, the transparent bottom-piece 4 and the transparent front portion 5 all have the same width coinciding with the distance between the internal faces of the two side bodies 1.

The upper surface of the two side bodies 1 has formed in it a plurality of wells 8 which may be closed by sealed flaps or lids and which are intended to act as containers for objects or as thermal cells for holding food.

A plurality of handles 7 housed in suitable recessed seats is formed on the side surfaces of the two side bodies 1.

The mode of operation of the craft forming the subject of the present invention will now be described in connection with the reference numbers indicated in the figures.

After the two halves forming the craft have been opened by rotating them about the hinge device 6, they are secured by means of the fastening devices 11; after this operation the craft is ready to be used.

The occupant takes up his/her position on it by resting their chest on the bottom-piece 2 and the transparent inclined surface 3 and, by moving their legs which are left free in the water, imparts a movement to the craft; at the same time the occupant is able to view constantly underwater, since he/she always has his/her face opposite the front chamber 10 and is able to see through both the transparent inclined surface 3 and the transparent bottom-piece 4 and the transparent front portion 5.

The craft may be advantageously used as a base camp for underwater research, as a rescue raft and as a means for transportation over short distances.

Two or more crafts may also be arranged alongside one other and fastened together so as to allow two or more people to move together or so as to form a larger size platform.

According to a preferred embodiment illustrated in Figure 6), 7), 8) and 9), the craft is composed of two parts: a rear part 20 provided with a transverse projection 21 located in the region of the end zone, leaving two channels 22 for draining the water and a front zone 23 which is connected to a bows zone 23a. In the bows zone there are formed through-holes 24 (two in the example illustrated) which have a substantially parallelepiped shape, but could also have another shape.

Each through-hole is lined with a tubular element 25 which has an internal abutment ring 26.

27 denotes a container with at least a transparent bottom-piece 28. The container is inserted into the tubular element 25 until it comes into contact against the abutment ring 26.

The container 27 is sealingly closed at the top by a lid 28 which may be personalised with different variations depending on the specific function for which it is intended.

For example, if used to hold a TV camera, on the outside it will be fitted with a watertight remote control unit or control devices for a photographic camera, or else it will provided with two small port-holes 29 which are closed by sealed lids and can be opened so as to allow simple inspection of the sea bottom and the release of

any vapour which has formed inside the container.

Each of the two parts is provided, moreover, with through-holes 30 and 31 transverse to the axis of the craft. Cords or rigid bars 32 are passed inside the through-holes 30 in order to join together the parts 20 and 23.

The transverse holes 31 may be used to join together, again by means of cords or bars, two or more craft arranged alongside one another so as to allow underwater viewing as a group.