The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 12, 2001
Filed:
Mar. 20, 2000
Michael A. Quadrini, Westerly, RI (US);
Pieter Van Dine, Mystic, CT (US);
Electric Boat Corporation, Groton, CT (US);
Abstract
A marine propulsion unit supported from a vessel by a strut contains an electric motor within a housing and a forward propeller driven by the electric motor and having a diameter larger than that of the housing. Hydrodynamic vanes projecting from the surface of the housing counteract tangential flow generated by the forward propeller. An aft section with a pair of counter-rotating blade rows driven by the electric motor is mounted at the rear of the housing and including a shroud surrounding the aft blade rows. The shroud is spaced from the housing so as to receive the boundary layer of liquid passing along the surface of the housing to inhibit cavitation and improve efficiency. Rearward portions of the shroud are movable to form a clamshell causing a reversal of the flow of the liquid passing through the shroud.