Patent ID: 8444391

Claim:
A marine propeller drive ( 1 ) for boats comprising: a gearbox ( 10 ) for a motor transmission and an associated impelling propeller ( 12 ), said propeller ( 12 ) being provided with a propeller hub 14 the main peripheral cross-section dimension (A) of which is less than the main peripheral cross-section dimension (B) of the gearbox ( 10 ) and in which a transition cone ( 18 ) is located between the gearbox ( 10 ) and the propeller hub ( 14 ); said transition cone ( 18 ) having a front end ( 20 ) located in connection with the gearbox ( 10 ), where said front end ( 2 ) has an initial peripheral cross-section dimension (C) essentially corresponding to the main peripheral cross-section dimension (B) of the gearbox ( 10 ) and a rear end ( 22 ) located in connection with the propeller hub ( 14 ), where said rear end ( 22 ) has a final peripheral cross-section dimension (D) essentially corresponding to the main peripheral cross-section dimension (A) of the propeller hub ( 14 ); said transition cone ( 18 ) further comprising a bulb-shaped shoulder part ( 24 ) located between said front end ( 20 ) and rear end ( 22 ), the largest peripheral cross-section dimension (E) of which exceeds the initial peripheral cross-section dimension (C) of the transition cone ( 18 ), wherein the largest peripheral cross-section dimension of the shoulder part ( 24 ) is located axially closer to the front end ( 20 ) of the transition cone ( 18 ) than to the rear end ( 22 ) thereof.