Lightweight power boat concept

Abstract

A three hulled T configuration displacement power boat that reduces weight by minimizing the structural without sacrificing boat length. The weight is evenly distributed between three hulls and is aligned in a T formation so that the overall boat length would be about three times the hull length. The structure, cargo and passenger(s) are supported above the water as shown in FIG. 1.

Claims

1. A power boat for travelling at service speed, most suitable for off shore protected waterways comprising: a) three semi-displacement hulls of equal length and equal beam, each about of overall boat length, wherein the three hulls comprise two aft hulls and one forward hull, each hull has vertical or nearly vertical sides and a pointed bow; b) a frame above a surface of the water at gross weight, said frame fixing said hulls in a right angle T-formation with about one hull length longitudinal distance between said two aft hulls and said forward hull; c) a load platform on said frame to support a load; d) a motor mounted on said platform that drives a propeller under the surface of the water; e) a foil mounted on each port and starboard side of each hull at the longitudinal midpoint of each of said hulls, each foil extends laterally from each hull; f) a rudder mounted on the keel of each of said rear hulls; g) longitudinal strakes mounted on a forward portion of each of said hulls above the surface of the water.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1Plan view of test model showing three equal size hulls in T configuration.

(2) FIG. 2Side view showing the preferred embodiment of hulls, Frame, load platform, load, and position of lifting foils.

(3) FIG. 3Top view showing the preferred embodiment of hulls, load platform, load, strakes and foils.

(4) FIG. 4Front view showing preferred embodiment.

DETAIL DESCRIPTION OF THE PREFERRED EMBODIMENTS

(5) Over the last 5 years have I've made and tested a 19.5 boat with 7 hulls per above design parameters. With a 20 hp motor this boat travels 18.5 mph in displacement mode and reaches this speed staying level. Boat's dry weight with motor is about 450 lbs.

(6) The top speed for this test model works out to be 5.8square root of hull length with foils that support about 30% of boat dry weight.

(7) Because the hulls are length, true comparison would be 3.3square root of overall boat length which is about twice the cruising speed of a mono hull power boat.

(8) The preferred embodiment would consist of three hulls 1 that are about boat length and met the following design parameters: Length to beam ratio of 8 to 1 Vertical sides+/6 degrees, Hull height about of hull length Sharp bow and stern angled back 25 degrees, Flat bottom, Front strakes 4, half length of hull, Foils 6, near center of buoyancy, large enough to support 50% of boat dry weight with motor at cruising speed.

(9) The preferred embodiment would have load platform/load 5 and motor as centrally located as possible to the center of flotation per FIG. 1 and rudders 7 mounted on back of back hulls as shown in FIG. 2

(10) According to preferred embodiment being described frame 3 can be held above the hulls by struts for more water clearance. Part of the frame holding back two side hulls can be raised even higher to give still greater water clearance in back.

(11) Per preferred embodiment strakes 4 would control water spray and help keep hulls from getting buried in large waves.

(12) Per preferred embodiment the combined foils would lift about 50% of the boat's all up weight at cruising speed.

(13) Alternative embodiment with big enough hull would be to mount motors in back hulls and do away with rudders 7. To balance motor weight in back hulls the platform with load would have to be located further forward. Alternative embodiment would make said foils' angle of attack adjustable to best balance speed, water clearance and turn control.