GB2050256A - Improvements in and relating to the construction of boat hulls - Google Patents

Abstract

A boat hull is described which whilst providing full 6 ft. headroom in a forward cabin in front of a driving position located at the forward end of a main cabin, nevertheless does not need to exceed 6ft 7ins. overall headroom to enable the craft to have access on restricted headroom rivers and waterways. The invention provides a hollow keel section at the forward end of the boat the base of which constitutes the floor (34) of the forward cabin and substantially horizontal underside sections of the boat hull between the chine and the hollow keel section constitute bases for berths 32 in the forward cabin. Access to the forward cabin is by way of a companion way closed by doors and at least one step (40) to accommodate the difference in level between the floor (34) of the forward cabin and the floor (38) of the main cabin. The main cabin floor is at or near the level of the horizontal underside sections of the boat hull between the chine and the keel. <IMAGE>

Description

SPECIFICATION Improvements in and relating to the construction of boat hulls Field of invention This invention concerns boat hulls and in particular a form of construction of hull which is suitable for use on inland waterways.

Background to the invention With leisure craft it is obviously desirable that as much of the cabin accommodation on board has full 6 ft. headroom to facilitate walking around and working below deck. On the other hand the conventional steering position for river craft has been from a centre or aft cockpit and in order to give visibility above the cabin roof and still maintain 6 ft. headroom within the cabin, the usual arrangement was to provide an elevated cockpit floor (whether in the centre or in the stern) to allow the person in charge of the vessel to see over the cabin roof. Typically a windscreen has been provided forward of the driving position and in many designs a cockpit roof or canopy has also been provided.However this has invariably meant that the overall height of the boat above the water line has tended to be well in excess of 6 ft. 6 ins. typically 7 ft. 6 ins. and more in order to accommodate the 6 ft headroom required within the cabin and to give approximately 1 8 ins. of windscreen. The basic problem arises from the fact that with typical displacements the cabin sole (i.e. the floor line) tends to approximate to the water line and in order to provide the 6 ft. headroom within the cabin it is thus necessary for the cabin roof to be at least 6 ft. above the water line.

Historically many of the bridges and overriver structures at locks and the like have only admitted limited headroom for vessels to pass underneath and particularly on the Norfolk Broads and on many of the picturesque rivers the typical clearance beneath many of the over-river structures is such that craft which are more than 6 ft. 6 ins. above the water line cannot pass thereunder.

With the more conventional design of craft this has necessitated facilities to fold down or collapse the windscreen and canopy structure over the cockpit whether this be in the centre or in the aft of the boat and this tended to mean that the cockpit became a single function area on the boat which was wasteful of space and after time the folding screen and associated collapsible canopy etc. has been a common source of leaks and has needed periodic maintenance.

During the 1960's a new design of river and inland waterway cruiser appeared. The forerunner of this new range of cruisers became known as the Caribbean cruiser and this was characterised by providing a forward steering and driving position much in the same way as is provided in a motor coach and apart from stowage everything else was placed to the rear of the driving position.

Since there was no cabin roof in front of the driving position, this could be at the same level as the remainder of the craft, the driver having an unrestricted forward view across the bows of the boat. The arrangement was popular with many of the hire craft fleets since by adopting a wide and essentially parallel hull form as well as providing a single level on which all the fittings and furniture were mounted, bought-out furniture could be fitted on board instead of going to the expense of custom-made units as is normally the case with other boats. The design was copied and from the accommodation point of view proved very popular but the design has always suffered from a serious drawback namely the poor rearward visibility from the driving position.

It is therefore an object of the present invention to overcome the problem of headroom for inland waterway and river craft by providing a design of boat hull which does not exceed the 6 ft. 6 ins. height requirement above the water line but will provide a more centrally located driving position and still give 6 ft. headroom within all the cabin accommodation.

The invention According to the present invention a hollow keel section is provided at least at the forward end of the hull with the depth of the hollow keel section being such as to give 6 ft.

headroom between the floor of the hollow keel section and a cabin roof situated thereabove and the width of the hollow keel section being sufficient to provide a walkway within the aforementioned cabin.

For obvious reasons the forward end of a boat hull is normally pointed and at least at the bows is of V-section and the invention is thus particularly applicable to boats in which the forward cabin has an arrangement of two berths known as V berths on port and starboard of the cabin with a generally triangular floor area between the two berths. The floor area in a forward cabin of this design is thus minimal and can be easily accommodated within a hollow keel section as provided by the invention and by providing a relatively flat underside to the hull between the keel and the chine, the additional buoyancy created by the rather wide and deep keel can be accommodated.

According to a preferred feature of the invention, the generally flat plateau on either side of the wide hollow keel section within the hull can be used to support the berths directly or through an intermediate structure located thereon. The intermediate structure may for example include stowage lockers or pull-out drawers.

It will be seen that the invention allows 6 ft.

headroom to be effectively obtained within a forward cabin of a generally flat-bottomed craft over the usual triangular floor area in the forward cabin where the 6 ft. headroom is actually required.

Clearly it is normally desirable to provide a wider floor area with true 6 ft. headroom in the main cabin located to the rear of the forward cabin and to this end the floor provided by the hollow keel section in the forward cabin is typically reached by one or more steps from the floor of the main cabin which will be at a level corresponding to the generally flat underside of the hull on either side of the keel between the keel and the chine of the boat and in order to provide the 6 ft. headroom requirement in the main cabin, the roof of the latter must of course be located above the level of the roof of the forward cabin by a distance at least equal to the difference between floor levels between the forward cabin floor and the main cabin floor.However by locating the driving position at the forward end of the main cabin immediately to the rear of a windscreen above the bulkhead between the forward and main cabin so unrestricted forward vision is provided for the driver and the driving position is now slightly forward of centre instead of being right forward as in the Caribbean design.

An added advantage is that the driving position is also elevated and relatively unrestricted vision will be available for the driver through the main cabin windows and to the rear through the entrance to the main cabin which to this end may be glazed to an aft cockpit.

The invention is applicable to any size of craft but is of particular advantage to a craft of approximately 28 to 35 ft. length overall.

This tends to be the most popular length for hire craft and leisure craft for inland waterways for multiple occupation i.e. from 4 to 6 persons and the invention may without difficulty be incorporated into a hull having an overall length in that range and a beam of up to 12 ft.

The design of the cabin accommodation to the rear of the forward cabin is relatively unimportant except for the proviso that the driving position should be located immediately to the rear of the bulkhead between the forward cabin and main cabin. The invention may thus be applied to a craft in which a cockpit is located aft of the main cabin or to a craft in which a cockpit area is located intermediate the forward cabin and a rear cabin.

The invention is equally applicable to boats constructed from wood, ferro-concrete, glass reinforced plastics materials and metal.

The invention will now be described by way of example with reference to the accompanying drawings.

In the drawings Figure 1 is a side elevation of a boat hull embodying the invention, Figure 2 is an illustration of the crosssectional shape of the hull when viewed from the bow end, Figure 3 is a side elevation of a completed cruiser showing the above-the-water line elevations using a hull form as shown in Figs. 1 and 2, Figure 4 is a plan view of the cruiser shown in Fig. 3 showing the internal layout which is possible as a result of the hollow keel section in the forward cabin provided by the invention, Figure 5 is a cross-sectional side elevation of the cruiser shown in Figs. 3 and 4 viewed from the port side, Figure 6 is a cross-sectional elevation of the cruiser of Figs. 3 and 4 when viewed from the' starboard side, Figure 7 is a perspective view from the rear cockpit of the internal layout of the craft shown in Figs. 3 to 6, and Figure 8 is a perspective view from the forward cabin position but with the bulkhead removed illustrating the internal layout when viewed from that standpoint.

Detailed description of drawings Dealing first with Fig. 1, a hull form is shown generally designated 10 with a water line shown at 1 2. Referring to Figs. 1 and 2, it will be seen that the hull has a very pronounced chine at 14 and 16 and an essentially flat underside between the chine and the keel. The main difference between this hull form and conventional river craft hull forms is that the thickness or width of the keel when viewed in cross-section over the majority of the length of the keel is considerably wider than conventional keels as shown at 1 8.

In all other respects the hull is of conventional construction and includes strengthening ribs at or adjacent the section lines shown in the side elevation of Fig. 1 and the wall of the hull may be formed from glass reinforced plastics material, metal, wood or ferro-concrete. As is conventional, at the stern end a propeller shaft protrudes through the rear end of the keel as denoted by reference numeral 20 and a rudder is located aft of the propeller at 22.

By adopting this hull form as denoted by Figs. 1 and 2 and by providing that the internal shape of the hull essentially follows the external contours shown in Fig. 2, a distinct advantage is obtained in the forward cabin. This can be seen by reference to Figs.

3 and 4.

Fig. 3 is a side elevation of the cruiser above the water line and the arrow 24 denotes the approximate driving position. It will be seen that this is approximately central and that the driver has virtually unrestricted vision forward and to port and starboard to a long way behind the driving position. This is quite different from the driving position in the Caribbean styled crusier in which the driving position is completely forward and vision to the rear is considerably restricted due to the presence of bulkheads and the like dividing up the interior of the Caribbean craft.

In Fig. 3 it will be seen that the forward cabin denoted by reference numeral 26 is apparently of very restricted headroom but by virtue of the invention, the headroom within the forward cabin is no different from the headroom in the main cabin containing the driving position 24, the main cabin being generally designated by reference numeral 28. The invention provides that whilst the floor level within the main cabin 28 is approximately at the water line, the floor level within the forward cabin is some 1 8 ins. below the water line and is wholly contained within the hollow keel section 1 8.

To provide an appropriate dynamic shape below the water line, the keel is obviously tapered towards the prow of the boat so that the side walls of the hollow keel section 1 8 will themselves taper towards the prow of the boat. However this is of little consequence in the forward cabin where the normal layout is to provide two berths port and starboard of the centre line of the craft as shown in the layout view of Fig. 4. Here the port berth is denoted by reference numeral 30 and the starboard berth by reference numeral 32. Between the two berths 30 and 32 is a floor section denoted by reference numeral 34 and this floor section is formed on the lower flat base of the box section keel 1 8 denoted by reference numeral 36 in Fig. 2.

Since this floor level 34 is below the floor level 38 in the main cabin 28 a step is provided between the two floor levels and this is shown more clearly in Figs. 5 and 6.

The step is denoted by reference numeral 40 and referring back to Fig. 4, conveniently a bulkhead exists as denoted by reference numeral 46 across the interior of the main cabin to divide the main cabin 28 from the forward cabin 26. An opening in the bulkhead 46 normally closed by a pair of doors 48 and 50 gives access to the forward cabin and to avoid loss of floor space in the forward cabin the step 40 is conveniently provided within the area of the main cabin 28 as shown in Fig. 4 by the rectangular area denoted by reference numeral 52. The step is denoted in Fig. 4 by the reference numeral 40.

The hollow keel which extends from the bows to the stern of the cruiser provides excellent storage space for water tanks and fuel tanks and the like under the main cabin and additionally provides an excellent well into which the engine 54 can be lowered. By arranging the entrance 56 to the main cabin 28 to the port side of the engine, the floor level 38 can be continued into the cockpit 58 as will be seen by reference to Figs. 5 and 6.

Here the floor in the cockpit is denoted by reference numeral 60 and it will be seen that this is of the same level as the floor 38 shown in the main cabin 28.

In order to give an idea of the advantage which can be obtained from this invention, two perspective views have been included in the drawings, one in Fig. 7 from the cockpit looking forward and one from the opposite standpoint at the bows of the boat with the forward bulkhead removed. The perspective view in Fig. 7 indicates the driving position denoted by reference numeral 28 with a raised helmsman seat at 64. Stowage locker 66 serves as a back rest for a dinette seat 68 and also as a base for a crew seat 78 at the same level or slightly higher than the helmsman's seat to allow crew sitting within the cabin also to have unrestricted forward visible ity.

The two doors 48 and 50 are also clearly visible as is the upper edge of the steps or companionway between the floor 38 of the main cabin and the floor level 34 within the forward cabin (not visible in Fig. 7).

Fig. 8 shows more clearly the change in levels between the main cabin floor level 38 and the level 34 of the floor in the forward cabin. The bulkhead 46 is largely cut away so as to reveal the interior of the main cabin and the doors 48 and 50 have been removed.

Referring once again to Figs. 5 and 6, it will be seen that the hollow box section keel beneath the forward cabin provides a generally triangular shaped floor 34 between two berths 30 and 32 and whilst the forward end of the hollow box section keel is boxed over by means of a false floor member 68, the level of which is substantially the same as the level of the floor 38 in the main cabin, the main floor in the forward cabin is at the level of the bottom of the hollow box section 1 8 as denoted by reference numeral 36 in Fig. 2.

In the event that the invention is applied to a hull of longer overall length than that shown the engine may be mounted off centre or located beneath a seat or vanitory unit in a cabin at the extreme stern of the craft thereby allowing a cockpit-type cabin within the centre and a true aft cabin in place of the coekpit shown in the cruiser illustrated.

Claims (11)

1. In a boat hull a hollow keel section is provided at least at the forward end of the hull with the depth of the hollow keel section being such as to give 6 ft. headroom between the floor of the hollow keel section and a cabin roof situated thereabove, the width of the hollow keel section being sufficient to provide a walkway in the fore to aft direction within the aforementioned cabin.

2. A boat as claimed in claim 1 in which the hull is pointed at the forward end and adjoining the bows is of generally 'V' section and the forward cabin has an arrangement of two berths known as 'V' berths on port and starboard sides of the cabin with a generally triangular floor area between the two berths, the triangular floor area being accommodated within the hollow keel section.

3. A boat as claimed in claims 1 or 2 in which the underside of the hull is relatively flat between the keel and the chine to accommodate the additional buoyancy created by the wide and deep keep keel.

4. A boat as claimed in any of the preceeding claims in which the inside surface of the hull on either side of the hollow keel section provides a support for berths directly or through an intermediate structure located thereon.

5. A boat as claimed in claim 4 in which the intermediate structure comrises stowage lockers or pull-out drawers.

6. A boat as claimed in any of claims 1 to 5 in which the floor in the main cabin located after the forward cabin is higher than the floor in the forward cabin and the latter is reached by one or more steps from the floor of the main cabin.

7. A boat as claimed in claim 6 in which the floor of the main cabin is at or near the level of the berths in the forward cabin.

8. A boat as clainied in any of claims 1 to 7 in which the roof of the main cabin is located above the level of the roof of the forward cabin by a distance at least equal to the difference between the floor levels of the forward cabin and main cabin.

9. A boat as claimed in claim 8 in which a driving position is provided at the forward end of the main cabin and a windscreen is provided between the roof of the forward cabin and the roof of the niåin cabin through which unrestricted forward vision is obtained from the aforementioned driving position.

1 0. A boat as claimed in any of the proceeding claims in which a bulk head is provided at the junction between the forward cabin and the main cabin.

11. A boat as claimed in any of the proceeding claims in which the hull of the boat is constructed from wood ferro-concrete glass reinforced plastics materials or metal or combinations thereof.

1 2. A boat constructed and arranged substantially as herein described with reference to and as illustrated in the accompanying drawing.