Stern thruster

Abstract

A stern thruster for use with a boat with at least one hull with a transom and an outboard motor that comprises: a powerhead; a mounting bracket attaching the outboard motor with respect to the hull; a midsection leg extending downwardly from the powerhead; a lower unit provided at a downward end of the midsection leg, the lower unit comprising a propulsion propellor configured to be positioned below a waterline of the hull. The stern thruster comprises: at least one thruster motor; at least one thruster propellor; a sleeve housing the at least one thruster motor and the at least one thruster propellor. The stern thruster is attached with respect to the transom, at a position below a waterline of the hull in use. The stern thruster is positioned between the midsection leg or lower unit of the outboard motor and the transom to provide lateral thrust to the hull.

1 . A boat with at least one hull and an outboard motor, the at least one hull having a transom wherein the outboard motor comprises:
 a powerhead;   a mounting bracket attaching the outboard motor with respect to the at least one hull;   a midsection leg extending downwardly from the powerhead;   a lower unit provided at a downward end of the midsection leg, the lower unit comprising   a propulsion propellor configured to be positioned below a waterline of the at least one hull in use,   
       the boat further comprising a stern thruster, the stern thruster comprising:
 at least one thruster motor; 
 at least one thruster propellor; 
 a sleeve housing the at least one thruster motor and the at least one thruster propellor; 
 
       wherein the stern thruster is attached with respect to the transom, at a position below a waterline of the at least one hull in use, with the stern thruster positioned between the midsection leg or lower unit of the outboard motor and the transom, the stern thruster configured to provide lateral thrust to the at least one hull. 
     
     
         2 . The boat of  claim 1 , wherein there is further provided a thruster mounting bracket, the thruster mounting bracket being attached to the transom and the stern thruster being attached to the thruster mounting bracket. 
     
     
         3 . The boat of  claim 2 , wherein the thruster mounting bracket is permanently attached to the transom and permits temporary removal and reattachment of the stern thruster. 
     
     
         4 . The boat of  claim 2 , wherein the stern thruster comprises a complementary connector configured to slide onto the thruster mounting bracket from above in a substantially downwards direction. 
     
     
         5 . The boat of  claim 2 , wherein at least one of the thruster mounting bracket and the complementary connector is shaped to permit the complementary connector to attach to the thruster mounting bracket in only one orientation. 
     
     
         6 . The boat of  claim 1 , wherein the stern thruster further comprises a second thruster motor and a second propellor. 
     
     
         7 . The boat of  claim 6 , wherein the sleeve provides a passage from one lateral side of the stern thruster to another lateral side of the stern thruster, each thruster motor being held within the passage such that water flows axially along the passage and around each thruster motor when operated to drive the respective thruster propellor. 
     
     
         8 . The boat of  claim 1 , wherein the at least one thruster propellor has a diameter of not more than 185 mm. 
     
     
         9 . The boat of  claim 1 , wherein the pontoon boat has a fore-aft direction extending between a bow and a stern of the pontoon boat and the at least one thruster propellor is rotatable about a rotation axis that is oriented transverse the fore-aft direction, and wherein the transom has a top and a bottom, and wherein the rotation axis is positioned not lower than the bottom of the transom. 
     
     
         10 . The boat of  claim 9 , wherein the rotation axis is positioned not more than a distance equal to the sum of the thruster propellor radius and 20 mm from the transom. 
     
     
         11 . The boat of  claim 1  wherein the sleeve has a waisted central portion facing the midsection leg or lower unit of the outboard motor in order to provide clearance between the stern thruster and the outboard motor. 
     
     
         12 . The boat of  claim 1  wherein the boat is a pontoon boat with at least two pontoon hulls. 
     
     
         13 . The boat of  claim 12 , wherein the pontoon boat has three pontoon hulls and the stern thruster is attached to a central one of said three pontoon hulls.