US3509842A - Sailing catamaran with pivoting hulls - Google Patents

Description

3 Sheets-Sheet 1 HULL ,9. B. MITCHELL SAILING CATAMARAN WITH PIVOTING HULLS May 5, 1970 Filed May 20, 1968 TH/Q/S BE/Q//V C/QT/V/Q/V- /D (//A/ INVENTOR May 5, 1970 c. B. MITCHELL 3,509,842

SAILING CATAMARAN WITH PIvoTING HuLLs Filed May 20, 1968 3 Sheets-Sheet 2 /MHJZ P/ V07 RHA/6E F7 THN/Q/Q/QAf/VD i//L/ INVENTOR.

May 5, 1970 c. B. MITCHELL 3,509,842

SAILING CATAMARAN WITH PIVOTING HULLS Filed May 20. 1968 3 Sheets-Sheet 3 56H57/ LOCK [PM/N50 No Toms Rf@ UAV/Q50) B-R//V LOCK l O 55cm/N5 PRH/v5 HC/L @0770/7 INVENTOR.

United States Patent O 3,509,842 SAILING CATAMARAN WITH PIVOTING HULLS Charles B. Mitchell, Loudonville, N.Y. (RD. 4, Ballston Spa, N.Y. 12020) Filed May 20, 1968, Ser. No. 731,366

Int. Cl. B231) 1/18 U.S. Cl. 114-61 2 Claims This invention is designed to overcome a common fault of all conventional sailing hulls, including the catamaran. This fault is that the conventional hull changes the angle of contact between hull surface and Surface of water upon being heeled over by wind. When this occurs there is a loss of efciency by the hull directly related to the angle of tilt. Severe heeling can result in lugging with little increase in speed and possible capsizing due to the changing for-ces acting upon the hulls varying surface.

The catamaran of this invention utilizes twin atbottomed hulls that are connected to a frame by parallel, bearing-held tubes such that the hulls can freely pivot over a range of A (see FIG. 2) degrees from center. The center line of the pivot bearing and tube is offset inward by distance X (see FIG. 2) from the hull center line. The pivot bearings are attached to the bottom of the hull to place it below the buoyancy line.

With the above described design the catamaran will always maintain the leeward hull in the same respective position to the water line. This is true even if the wind causes sufficient heeling to lift the Windward hull clear of the water due to the tilt of the mast and frame.

Therefore, the advantages to be gained are numerous. As the Wind forces build, both horizontal and vertical forces against the leeward hull increase as it maintains its same position relative to the water line. This gives increased resistance to side drift and increased lift, respec- "lee tively. From this, additional speed is gained since water friction is reduced.

FIG. l and FIG. 2 illustra-te how the hulls are attached to the frame by the pivot bearings and the relative position of the pivot center line with respect to the hull center line. Angle in FIG. 2 is the angle that would be maintained by the leeward hull as the frame is pivoted in the wind through angle 7x.

FIG. 3 illustrates the construction of the pivot bearing assembly. Its simplicity and the ease with which the tube may be inserted and removed should be noted. Simply by throwing back the safety lock, swinging up the bearing lock and then the hold down bearing bar the way is clear for the tube to be lifted out. This is a highly desirable featureto provide quick dismantling and/or assembly and ease of transportability.

Having thus described the invention, what I claim as new and desire to be secured by Letters Patent is as follows:

1. A sailing catamaran where each hull of said catamaran is hinged at the bottom of the supporting arms: the pivots being offset inwardly from each hulls centerline so as Ito cause the outside of each hull to ride higher than the inside at a predetermined angle, whereby regardless of the heeling of the catamaran due to wind force, the hull always maintains the same angle to the water level.

2. A sailing catamaran where each hull of said catamaran is pivoted, the pivots being offset inwardly from each hulls centerline so that the hulls ride at a predetermined angle to the water level so that when running into or across the wind the lee hull is always planing into thewind and fighting against drifting to leeward.

References Cited UNITED STATES PATENTS 3,116,708 1/ 1964 Gardhouse 114-61 ANDREW H. FARRELL, Primary Examiner U.S. C1. X.R. 114-39

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