US 12,403,999 B2
Marine propulsion system supported by a strut
Andrew Orvieto, Plantation, FL (US); Keith Stanley, Coral Springs, FL (US); Dave Gruenwald, Oshkosh, WI (US); and Bryan Danner, Oshkosh, WI (US)
Assigned to ZF Friedrichshafen AG, Friedrichshafen (DE); and ZF MARINE PROPULSION SYSTEMS MIRAMAR, LLC, Miramar, FL (US)
Filed by ZF FRIEDRICHSHAFEN AG, Friedrichshafen (DE); and ZF MARINE PROPULSION SYSTEMS MIRAMAR, LLC, Miramar, FL (US)
Filed on Mar. 3, 2022, as Appl. No. 17/685,550.
Prior Publication US 2023/0278690 A1, Sep. 7, 2023
Int. Cl. B63H 23/06 (2006.01); B63H 23/34 (2006.01); B63H 25/38 (2006.01); B63H 23/02 (2006.01)
CPC B63H 23/06 (2013.01) [B63H 23/34 (2013.01); B63H 25/38 (2013.01); B63H 2023/0283 (2013.01); B63H 2023/067 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A marine propulsion system, supported by a strut, comprising:
an inner propeller shaft supporting a first propeller adjacent a trailing end thereof, and the inner propeller shaft having an interface, at a leading end thereof, to facilitate connection with a drive shaft for receiving torque therefrom and supplying a first portion of the torque to the first propeller;
an outer propeller shaft supporting a second propeller, adjacent a trailing end thereof, and the outer propeller shaft surrounding the inner propeller shaft;
the strut having a strut through bore for accommodating and surrounding the inner and the outer propeller shafts, and the strut having a flat end face configured to abut an outwardly facing bottom surface of a hull of a vessel; and
a planetary gear assembly for receiving a second portion of the torque from the drive shaft and supplying the second portion of torque to the outer propeller shaft so that the second propeller rotates in an opposite rotational direction than the first propeller;
wherein at least a portion of the planetary gear assembly is accommodated vertically above the flat end face of the strut for reducing hydrodynamic drag generated by the strut as the marine propulsion system travels through water.