The present invention relates to the construction of power boats in FRP (Fibre Reinforced Plastic.) and in particular to a a type of construction which enhances the suitability of FRP power boats for mass production. Over the last thirty years there has been a massive swing in the pleasure boat industry towards FRP construction and although many power boat builders are still operating on quite a small scale there are a number of boat building factories throughout the world which are putting great efforts into trying to streamline the production process for FRP power boats in order to try and achieve the economies which flow from mass production in other industries such as the motor industry.

One of the basic problems which inhibits true mass producti of FRP power boats is that all mouldings and fittings must be individually located on the hull. This necessitates a . numbe of tradesmen being present in one confined hull at the same time or alternatively if only one or two tradesmen can work in a hull at any one time the production process is greatly retarded. As the hull of a boat is necessarily quite large and. relatively difficult to move it is also necessary for a tradesmen to bring all his tools to the particular hull being worked on rather than the hull being transported around a factory so as to be handy to the particular tools used by each tradesmen. While some progress has been made in the production of FRP boats by the separate laying up of FRP liners and furniture such that the

anufacture of such furniture may take place in an area remote from the hull there is still the necessity to glass such liners, bulkheads etc to the hull. Glassing individual components to the inside of a hull is a time consuming exercise since the resin in the hull has already set and therefore it is necessary to grind itdom in order that it may bond adequately to ^" other components which need to be glassed to the hull.

It is the object of the present invention to ameliorate one or more of the abovementioned disadvantages inherent in the design of modern power boats such that the production process may be more streamlined.

According to the present invention there is provided a FRP power boat wherein the principal structural assembly comprising the boat and intended to resist and distribute the various stresses and other forces operating on the boat by reason of its engines and the sea is not the hull but a central core within the hull comprised of two or more modules; the modules defining the bulkheads, floor and sides of the boat and including the engine mounts; the hull being substantially independent from said engine mounts, bulkheads and core generally except for a join between the core and hull adjacent deck level such join being adequate to locate the hull with respect to the core in such a manner that the hull may streamline the bottom of the core and prevent sea water contacting the bottom of the core.

One embodiment of the present invention will now be described with reference to the accompanying drawing in which: Figure 1 depicts partially cut away exploded perspective view of a core and hull in accordance with the present invention.

The embodiment of figure 1 depicts a core 1 comprising a foreward module 2, a central engine module 3 and an aft module 4. In conventional building practice bulkheads are glassed ^' into the hull which is a time consuming exercise not capable of being undertaken in an area remote from the hull. It will be noted that in accordance with the present invention each of modules 2, 3 and 4 include a bulkhead face. Bow module 2 includes bulkhead face 5 which is intended to abut bulkhead face 6 on module 3. These bulkhead faces are glassed (straped) together in order that modules 2 and 3 may become unitary. The rear of module 3 and the front of module 4 similarly terminate in a bulkhead face which bulkhead faces are joined to complete the core structure. The fact that each module includes a bulkhead greatly enhances the rigidity of the module and hence the composite core structure when each complete bulkhead is formed by joining of the two faces. Each module may further include, in a unitary manner a deck moulding in order that it may be formed as a complete box section thereby further enhancing rigidity although the embodiment of figure 1 does not rely upon such deck moulding for additional rigidity. It should be appreciated

that module 3 contains a well 7 which is intended to carry an engine and this well is provided with engine beds (not shown) in order that it may transfer all of the thrust imparted to the engine(via the propellor shaft)to the core. As one of the advantages of constructing a boat in accordance with the present invention is the avoidance of a time consuming step of fitting bulkheads and other fittings to the hull a boatin accordance with the present invention may additionally incorporate a central drainage system comprising a longitudinal tube(not shown)running substantially centrally of th core and underneath the core with branch lines communicating with sinks, showers etc. This tube would terminate adjacent the rear of the vessel in a sump (not shown) and be provided with a pump out system. This central drain system would also serve to impart additional rigidity to the core comprising the asssembled modules.

It will be appreciated that the modules may be fabricated in differring parts of one factory or indeed in separate factories on a production line and not necessarily by shiprights. The modules may then be assembled into the core unit quite independentl of fabrication of the hull and the glassing together (straping) of the bulkheads and other parts of the modules will not involve glassing into corners as is the case when a conventional bulkhead is fitted to a hull. The glassing of corners is a time consuming exercise. When the entire core is ready it may then be fitted to the hull by fixing means along flange 8 and hull flange 9.

It is envisaged that as the core is the basic structural unit of the boat it may be say fifty per cent heavier than conventional FRP mouldings comprising the interior of a boat. The hull however may be fabricated so as to be say fifty per cent lighter than that of a normal boat as its purpose is merely to keep the water away from the core and to streamline the underside of the core. The hull 9 however will still be subject to pounding and other forces and consequently a light reinforcement matrix 10 is glassed into the hull. The reinforcement matrix distributes local stresses within the hull and bearers 13 may also contact the lower portions of core 1. Core 1 however is not rigidly affixed to the reinforcement matrix. Cushioning material (not shown) may be provided between the core 1 and such bearers 13. There will of course be the necessity for a stern tube and possibly toilet fittings passing between the core and the hull and the ingress of water into the area between the hull and core will be avoided at these points by the inclusion of flexible boots (not shown). In order to provide for the uptake of sea water for cleaning purposes and otherwise

into the vessel it is also possible in this embodiment to provide one or more holes (not shown) in the hull which holes communicate with the channels formed between the reinforcement matrix 10 and the hull 9 when the reinforcement matrix is glassed in place. In this manner that part of the reinforcement matrix below the water line would be permanently filled with water which may be tapped at any point on the reinforcement matrix below the water line and in particular it may be conveniently tapped on one of the vertical members comprising the matrix along the side such as 12. In this manner the provision of a skin fitting on the hull is avoided.

In this embodiment the core itself is water tight below the line of the gunwaleand could actually be placed in the water and driven through the water by its engines. This is due to the fact that the structural rigidity of the boat is imparted from the core. This is an additional safety feature should a hull be holed or damaged. This feature would additionally facilitate ready replacement of a hull in the case of severe damage as the hull would merely be unbolted from flange 8 and a new hull placed around the core. Such a replacement(which is of course not possible with conventional FRP boats ) • would also be a relatively cheap way of replacing a hull which had succumbed to osmosis. .

Further economies are encountered when a boat is constructed in accordance with the embodiment of figure 1 as it is not necessary to flow coat the inside of a hull.

It should be appreciated that whilst not departing from the basic concept of a core substantially irdepa lent from thehull endvhidi imparts most of the structural rigidity to a boat it is possible to devise other embodiments apart from that above described without departing from the scope of the present invention.