US 7,070,468 B2Granted

Multi-hull watercraft with amidships-mounted propellers

AssigneeLockheed Martin Corporation

InventorTerrence W. Schmidt

Life of this patent

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Abstract

An efficient double-ended watercraft is disclosed that comprises four low-Froude number hulls: two forward, two aft, two on the port side, and two on the starboard. Each hull comprises an independent engine that drives a propeller shaft and propeller that is located amidships. The propeller shafts on the starboard are collinear, as are the propeller shafts on the port. The propellers on the starboard are near each other and counter rotate, as do the propellers on the port. The propellers are variable-pitch propellers. When the ferry is changes from moving forward to moving in reverse and from reverse to forward, the propellers on the starboard exchange pitch. This enables the ferry to move as efficiently in reverse as it does when forward. The propellers on the port also exchange pitch when changing from moving forward to moving in reverse and from reverse to forward.

Claims8

Dependent claims

A watercraft comprising:

a first hull that is buoyant in water;
a second hull that is buoyant in water;
a third hull that is buoyant in water;
a fourth hull that is buoyant in water;
a first propeller shaft that extends from a first end of said first hull towards said second hull, wherein said first end of said first hull is the only end of said first hull from which any propeller shaft extends;
a second propeller shaft that extends from a first end of said second hull towards said first hull, wherein said first end of said second hull is the only end of said second hull from which any propeller shaft extends;
a third propeller shaft that extends from said a first end of said third hull towards said fourth hull, wherein said first end of said third hull is the only end of said third hull from which any propeller shaft extends;
a fourth propeller shaft that extends from a first end of said fourth hull towards said third hull, wherein said first end of said fourth hull is the only end of said fourth hull from which any propeller shaft extends;
and
a superstructure connected to said first hull, said second hull, said third hull, and said fourth hull;
wherein said first hull, said second hull, said third hull, and said fourth hull provide substantially all of the buoyancy of said watercraft.

8 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/883,058Filed 1 Jul 2004
Published: US 2006/0000398 A15 Jan 2006
Granted: 4 Jul 2006
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

B63B 1/107
With multiple hulls: semi-submersibles; Small waterline area multiple hull vessels and the like, e.g. SWATH
B63B 1/12
With multiple hulls: the hulls being interconnected rigidly
B63H 5/08
Of propellers: of more than one propeller
B63B 35/54
Vessels or similar floating structures specially adapted for specific purposes and not otherwise provided for: ferries