GB2098136A

GB2098136A - Variable configuration hull

Info

Publication number: GB2098136A
Application number: GB8113956A
Authority: GB
Original assignee: ANDERSON IAN LINDSAY
Current assignee: ANDERSON IAN LINDSAY
Priority date: 1981-05-07
Filing date: 1981-05-07
Publication date: 1982-11-17

Abstract

A power boat has a displacement hull which acquires the ability to plane when conditions are appropriate by having hull portions approximately amidships that are comparatively flat and comparatively horizontal and aft from which the hull narrows and steepens and sweeps to the water line, and by having a pair of displaceable surfaces 8 located in the aft hull portion which are moveable between extended and retracted positions about hinge lines 8a extending from points adjacent the stern near the centre line outwards and forwards to points near the water line. The hull has a first configuration in which the surfaces are in their retracted positions so that the hull forms a displacement hull, and a second configuration in which the surfaces are in their extended positions and cooperate with the amidships portions to form planing surfaces for the hull. A propeller 6 is retractable for sailing purposes and a forward centre plate is hinged for retraction when planing. <IMAGE>

Description

SPECIFICATION Boats This invention relates to boats for operation under different conditions.

According to the invention, such a boat comprises a hull designed to operate at low speeds as a "displacement" hull, for example a round bilge or multi-chine or double-chine hull, in which there are portions approximately amidships that are comparatively flat and comparatively horizontal aft from which the hull narrows and steepens and sweeps upwards to the waterline, the aft portion being characterised by a pair of surfaces displaceable out of the hull section about a line extending from a point towards the centre line forwards to a point further outwards of the centre line; the arrangement being such that the said amidships portion and the said surfaces combined are adequate to enable the boat to plane.

The boat may be a sailing boat or a motor craft the basic hull shape of which is a displaceable hull such as a fishing boat. The application of the invention would thus permit the boat to be used as a planing boat, e.g. when lightly loaded and in reasonably fair weather, but could revert to normal operation in other conditions.

Although a multi-chine or double-chine hull is possible a smooth contour is preferred and one form of the invention will now be described with reference to the accompanying drawings in which: Figure lisa typical aft and fore section of a displacement type sailing hull, Figure 2 is a typical aft and fore section of a power planing hull, Figure 3 is an elevational sketch of a boat to which the invention has been applied, when in the sailing mode, Figure 4 is a view similar to Figure 3 but in the power mode, Figure 5 is a perspective sketch of the after underside of the hull corresponding to the condition shown in Figure 3, and Figure 6 is a perspective sketch similar to Figure 5, corresponding to the condition shown in Figure 4.

Referring first to Figures 1 and 2, there is shown typical after and forward hull sections of conventional shapes for respectively a displacement sailing hull and a power planing hull. It will be seen that these shapes are totally different. In Figures 3 and 4 however, which show one application of the invention the hull 1 has a centre plate 2 and a sailing rudder 3. The bottom section is rounded and faired in the manner illustrated in Figure 1.An engine 4 is located just ahead of the cockpit area and is mounted in conjunction with a false transom 5 through which it can drive a propeller 6 by means of a folding transom drive 7. A pair of approximately triangular hull sections 8 are completely retracted into the hull in Figure 3 so as to present an uninterrupted outer surface, so the hull can be designed as an ideal sailing shape.

In Figure 4the necessary changes have been made to convert the hull to a shape suitable for planing under power. The centre plate 2 has been raised into its casing, the rudder 3 has been retracted to have a smaller effective area, the transom drive leg 7 has been lowered to place the propeller 6 in its operative position, and the hull sections 8 have been moved downwards about hinge lines 8a. The effect of this is shown more clearly in Figures 5 and 6which are perspective sketches showing the after underside of the hull in the conditions illustrated respectively in Figures 4 and 3. It will be seen that the hinge line 8a extends from a point adjacent the stern near the centre line outwards and forwards to a point near the water line on the outside of the hull. Although this appears as a curve in this view it can in fact be a straight line.The outside of the wedge section 8 can be arranged to coincide with a strake or chine so that the slight discontinuity introduced by having a separate section is kept to a minimum in its effect.

It will also be seen from Figures 5 and 6 that when the leg of the transom drive unit 7 is retracted the continuity of the hull for sailing is maintained by a pair of doors 9 conforming to the hull contour. These doors and the displaceable hull sections 8 are controlled from inside the boat and may be moved by means (not shown) which may consist of hand levers or mechanical, electrical or hydraulic actuators.

The displaceable portions of the hull may be in the form of plates which follow the hull shape or are flexed to adapt to it, or they may be solid bodies which fit into recesses in the hull so that when extended they have sides that reduce turbulence when planing; they are also stronger and can be arranged to prevent the ingress of foreign bodies.

1. A power boat having a variable hull configuration comprising hull portions approximately amidships that are comparatively flat and comparatively horizontal, aft from which the hull narrows and steepens and sweeps to the water line, and a pair of displaceable surfaces located in the aft hull portion, the surfaces being moveable between extended and retracted positions about hinge lines extending from points adjacent the stern near the centre line outwards and forwards to points near the water line, said hull having a first configuration in which the surfaces are in their retracted positions so that the hull forms a displacement hull, and a second configuration in which the surfaces are in their extended positions and cooperate with the comparatively flat and comparatively horizontal amidships portions to form planing surfaces for the hull.

2. A power boat according to claim 1 characterised in that the displaceable surfaces are formed by flexible plates which are arranged to adapt to the surface of the hull when retracted.

3. A power boat according to claim 1 characterised in that the displaceable surfaces are formed by rigid plates which follow the basic hull shape.

4. A power boat according to claim 3 characterised in that the plates are provided with side cheeks, the hull being provided with cavities to accommodate the plates and side cheeks when retracted.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Boats This invention relates to boats for operation under different conditions. According to the invention, such a boat comprises a hull designed to operate at low speeds as a "displacement" hull, for example a round bilge or multi-chine or double-chine hull, in which there are portions approximately amidships that are comparatively flat and comparatively horizontal aft from which the hull narrows and steepens and sweeps upwards to the waterline, the aft portion being characterised by a pair of surfaces displaceable out of the hull section about a line extending from a point towards the centre line forwards to a point further outwards of the centre line; the arrangement being such that the said amidships portion and the said surfaces combined are adequate to enable the boat to plane. The boat may be a sailing boat or a motor craft the basic hull shape of which is a displaceable hull such as a fishing boat. The application of the invention would thus permit the boat to be used as a planing boat, e.g. when lightly loaded and in reasonably fair weather, but could revert to normal operation in other conditions. Although a multi-chine or double-chine hull is possible a smooth contour is preferred and one form of the invention will now be described with reference to the accompanying drawings in which: Figure lisa typical aft and fore section of a displacement type sailing hull, Figure 2 is a typical aft and fore section of a power planing hull, Figure 3 is an elevational sketch of a boat to which the invention has been applied, when in the sailing mode, Figure 4 is a view similar to Figure 3 but in the power mode, Figure 5 is a perspective sketch of the after underside of the hull corresponding to the condition shown in Figure 3, and Figure 6 is a perspective sketch similar to Figure 5, corresponding to the condition shown in Figure 4. Referring first to Figures 1 and 2, there is shown typical after and forward hull sections of conventional shapes for respectively a displacement sailing hull and a power planing hull. It will be seen that these shapes are totally different. In Figures 3 and 4 however, which show one application of the invention the hull 1 has a centre plate 2 and a sailing rudder 3. The bottom section is rounded and faired in the manner illustrated in Figure 1.An engine 4 is located just ahead of the cockpit area and is mounted in conjunction with a false transom 5 through which it can drive a propeller 6 by means of a folding transom drive 7. A pair of approximately triangular hull sections 8 are completely retracted into the hull in Figure 3 so as to present an uninterrupted outer surface, so the hull can be designed as an ideal sailing shape. In Figure 4the necessary changes have been made to convert the hull to a shape suitable for planing under power. The centre plate 2 has been raised into its casing, the rudder 3 has been retracted to have a smaller effective area, the transom drive leg 7 has been lowered to place the propeller 6 in its operative position, and the hull sections 8 have been moved downwards about hinge lines 8a. The effect of this is shown more clearly in Figures 5 and 6which are perspective sketches showing the after underside of the hull in the conditions illustrated respectively in Figures 4 and 3. It will be seen that the hinge line 8a extends from a point adjacent the stern near the centre line outwards and forwards to a point near the water line on the outside of the hull. Although this appears as a curve in this view it can in fact be a straight line.The outside of the wedge section 8 can be arranged to coincide with a strake or chine so that the slight discontinuity introduced by having a separate section is kept to a minimum in its effect. It will also be seen from Figures 5 and 6 that when the leg of the transom drive unit 7 is retracted the continuity of the hull for sailing is maintained by a pair of doors 9 conforming to the hull contour. These doors and the displaceable hull sections 8 are controlled from inside the boat and may be moved by means (not shown) which may consist of hand levers or mechanical, electrical or hydraulic actuators. The displaceable portions of the hull may be in the form of plates which follow the hull shape or are flexed to adapt to it, or they may be solid bodies which fit into recesses in the hull so that when extended they have sides that reduce turbulence when planing; they are also stronger and can be arranged to prevent the ingress of foreign bodies. CLAIMS

5. A power boat according to claim 4 characterised in that the side cheeks are part of a solid wedge of which the lower surface constitutes the displaceable surface.

6. A power boat according to any one of the preceding claims characterised in that in addition to a pair of displaceable planing supporting surfaces the members forming these surfaces, or additional members, are also displaceable in such a way as to form a step in the hull bottom.

7. A power boat according to any one of the preceding claims characterised in that a flooded compartment is provided having an open or openable bottom formed in the hull surface ahead of the stern of the vessel for a drive unit which when not in use can be drawn upwards into the flooded compatment.

8. A power boat according to claim 7 characterised in that the forward wall of the compartment is formed as a bulkhead through which a transom drive operates.

9. A power boat according to any one of the preceding claims and substantially as herein described.