GB2313344A

GB2313344A - Watercraft

Info

Publication number: GB2313344A
Application number: GB9611056A
Authority: GB
Inventors: Reginald Frederick Clarke; John Chesney
Original assignee: Compass Group PLC
Current assignee: Compass Group PLC
Priority date: 1996-05-23
Filing date: 1996-05-23
Publication date: 1997-11-26
Anticipated expiration: 2016-05-23
Also published as: GB2313344B; GB9611056D0

Abstract

A watercraft is provided with a hull 1 which has a planing element 2 the lower surface of which forms a planing surface extending aft from the bottom of the fullest transverse section 3 of the hull to the stem end 5 of the base line 6 of the craft or just above it, and the transverse breadth of which at the fullest transverse section is substantially the same as the fullest transverse section 3 of the craft. The lower surface of the planing element 2 is angled upwardly from its lowermost point to the aft end of the base line by up to 15{. The planing element may have a tapering breadth towards the stern.

Description

WATERCRAFT This invention relates to a watercraft which may be used for sailing using wind power and which can be used as a planing craft when being mechanically propelled.

The intention is that the hull can be used when sailing but is so shaped that when being mechanically propelled it can plane at high speed, for example, up to 20 knots.

According to the present invention a watercraft is provided with a hull which has a planing element, the lower surface of which forms a planing surface extending aft from the bottom of the fullest transverse section of the hull to the after end of the base line of the craft or just above it, and the transverse breadth of which is substantially the same as the fullest transverse section of the craft.

The lower portion of the hull may decrease in cross section from the fullest transverse section to the after end, the planing element projecting transversely from the lower portion thereof.

With this arrangement the planing element can have a substantially constant transverse breadth.

Alternatively the planing element can have a tapering breadth from a broadest width at the fullest transverse section of the hull towards the stern.

Preferably the lower surface of the planing element is angled upwardly from its lower most point at the fullest section of the craft to the after end of the base line by up to 15".

The preferred angle is between 3 and 7".

In one convenient construction the planing element is separate from the hull and can be raised and lowered.

With this arrangement the planing element can be hinged to the hull at its forward end and can be provided with fixed or adjustable trim tabs.

The invention can be performed in various ways but some embodiments will now be described by way of example and with reference to the accompanying drawing in which: Figure 1 - is a diagrammatic side view of the hull of a watercraft according to the present invention Figure 2 - is a plan view from beneath the watercraft shown in Figure 1 Figure 3 - is an end view showing the stern of the watercraft shown in Figures 1 and 2 Figure 4 - is an end view of the stern, of an alternative construction, and Figure 5 - is a diagrammatic side view of another alternative construction in which the planing element can be raised and lowered As shown in Figures 1 to 3 the watercraft comprises a hull 1 which is provided with a planing element 2 which is in the form of a substantially flat plate. The element 2 extends aft from the bottom of the fullest transverse section indicated by reference numeral 3 of the hull 1. The after end 4 of the planing element 2 extends aft to the after end 5 of the base line 6 of the craft or, as shown in Figure 1 just above it. As will be seen from Figure 2 the transverse breadth of the element 2 is substantially the same as the fullest transverse section 3 of the craft, and the element 2 is secured or built integral with the bottom 7 of the hull.

The water line of the hull is indicated by reference numeral 8 so that when the craft is sailing using wind power the planing element is substantially submerged unless the craft is healed when the windward side may be lifted out of the water. When the craft is mechanically propelled the planing element allows the hull to lift and plane on its lower surface 9.

As mentioned above the planing element is substantially flat but if desired it could be slightly V-shaped in cross section to provide stability.

In Figure 1 the lower surface 2 of the planing element is angled upwardly from its lower most point at the fullest section 3 and the aft end of the base line 5 by about 3-. This angle will depend upon the design of the craft and its function and it could be up to about 15 , although it is preferably between about 30 and 7'.

The breadth of the planing element 2 shown in Figures 1, 2 and 3 is substantially constant, but it could have a tapering width from a broadest width at the fullest transverse section 3 of the hull towards the stern.

Figure 4 shows a construction in which the bottom of the hull is shaped to provide a skeg 10 rather than the hull being shaped into the planing element 2.

In Figure 5 the same reference numerals used to indicate similar parts, but in this construction a planing element 12 is provided which is of similar general outline to that described with regard to Figures 1, 2 and 3, but which is hinged at its forward end 13 at the fullest transverse section 3 of the hull. A power or manually operated ram 14 can be used to lower the planing element 12 from its raised position to a lowered position which is shown in chain lines 15. With this arrangement the angle of the planing element can be varied to suit the sea conditions and if required trim tabs 16 can be incorporated in the planing element 15 to facilitate trim during planing conditions or to stabilise the craft when sailing.

In order to improve the windward performance of the craft one or more drop keels or a centre board or centre boards can be provided.

Any convenient form of power drive can be used, for example an outboard motor or an inboard motor driving a propeller aft of the planing element 2.

Claims

1. A watercraft provided with a hull having a planing element the lower surface of which forms a planing surface extending aft from the bottom of the fullest transverse section of the hull to the after end of the base line of the craft or just above it, and the transverse breadth of which is substantially the same as the fullest transverse section of the craft.

2. A watercraft as claimed in claim 1 in which the lower portion of the hull decreases in cross section from the fullest transverse section to the after end and the planing element projects transversely from the lowest portion thereof.

3. A watercraft as claimed in claim 2 in which the planing element has a substantially constant transverse breadth.

4. A watercraft as claimed in claim 2 in which the planing element has a tapering breadth from a broadest width at the fullest transverse section of the hull towards the stern.

5. A watercraft as claimed in claims 1 to 4 in which the lower surface of the planing element is angled upwardly from its lowermost point at the fullest section of the craft to the aft end of the base line by up to 15".

6. A watercraft as claimed in claim 5 in which the angle is between 3 and 7".

7. A watercraft as claimed in any one of the preceding claims in which the planing element is separate from the hull and can be raised and lowered.

8. A watercraft as claimed in claim 7 in which the planing element is hinged to the hull at its forward end.

9. A watercraft as claimed in claims 1 to 8 provided with fixed or adjustable trim tabs.

10. A watercraft substantially as described herein with reference to and as shown in Figures 1 and 2, Figure 3, Figure 4 and Figure 5.