Vessel with rotatable pod

Abstract

A vessel and a method for driving a vessel. The vessel is provided with a pod arranged at the rear side thereof which is arranged rotatably with respect to the vessel. Rotation is effected about an axis which deviates slightly from the vertical. The axis of the propeller shaft forms an angle which is smaller than 90° with the axis of rotation of the pod. As a result of this combined positioning of the rotation shaft of the pod and the positioning of the propeller shaft, the axis of the propeller shaft with respect to the horizontal will vary when the pod is rotated depending on the rotation position of the pod. This permits optimum adaptation to the various operating conditions of the propeller position.

1 . Water-displacement vessel ( 1 ) comprising a hull with a longitudinal axis ( 15 ), comprising a bottom and comprising a pod drive ( 2 ) arranged close to the bottom, said pod drive ( 2 ) being provided with a housing ( 4 ) containing a propeller shaft ( 5 ) which protrudes through the housing and to which propeller shaft ( 5 ) a propeller is attached at a propeller end, and a drive for said propeller shaft, which propeller shaft ( 5 ) defines a first axis ( 7 ), which housing ( 4 ) is rotatable with respect to the hull between a rearward position and a forward position about a rotation shaft ( 9 ,  29 ) which defines a second axis ( 12 ,  32 ) which is not vertical and forms an angle (α) of 40°-90°, preferably between 60°-80°, with the first axis, characterized in that an annular jet pipe ( 17 ) is arranged around the propeller, comprising a peripheral edge ( 11 ) which is at a distance from the propeller shaft ( 5 ) and is situated further below a predetermined waterline in the forward position than in the rearward position, wherein the direction of rotation of the propeller shaft ( 5 ) in the forward position is adjustable in such a way that the jet pipe has a water-suction effect. 
     
     
         2 . Water-displacement vessel according to  claim 1 , comprising an elongate hull which is provided with a front end and a rear end, wherein the pod is attached close to the rear end, wherein, in the case of a low degree of loading, the peripheral edge ( 11 ) is situated close to or above the waterline in the rearward position and is situated a distance of at least in the order of 10% of the propeller diameter below the waterline in the forward position. 
     
     
         3 . Water-displacement vessel according to  claim 1 , wherein the first axis ( 7 ) is substantially parallel to the longitudinal axis ( 15 ) in the rearward position. 
     
     
         4 . Water-displacement vessel according to  claim 1 , wherein the pod is designed, in the case of a low degree of loading, to drive the vessel in the forward position by means of suction and, after a predetermined speed has been reached, to rotate about the rotation shaft ( 9 ,  29 ) into the rearward position, with reversal of the direction of rotation of the propeller. 
     
     
         5 . Water-displacement vessel according to  claim 1  wherein the second axis ( 12 ,  32 ) forms an angle (β) of 5-30° with the vertical in the position of use. 
     
     
         6 . Water-displacement vessel according to  claim 1 , wherein the hull is inclined with respect to the horizontal at the location ( 3 ) where the pod ( 2 ) is attached to the hull, and wherein the second axis ( 12 ) is perpendicular to the hull at the location of the attachment. 
     
     
         7 . Water-displacement vessel according to  claim 1 , wherein said hull comprises a vertical central longitudinal plane and said second axis ( 12 ) is situated in said vertical central longitudinal plane or in a plane parallel thereto. 
     
     
         8 . Water-displacement vessel according to  claim 1 , wherein said hull comprises a vertical central longitudinal plane, two pods are present on either side of said plane, wherein the second axes ( 12 ) of said pods are arranged mirror-symmetrically with respect to said vertical central longitudinal plane. 
     
     
         9 . Water-displacement vessel according to  claim 8 , wherein one pod can be moved into a rearward position while the other pod is in a forward position. 
     
     
         10 . Water-displacement vessel according to  claim 8 , wherein the second axes ( 12 ) are not in a plane parallel to said central longitudinal plane. 
     
     
         11 . Water-displacement vessel according to  claim 1 , wherein the jet pipe ( 17 ) is annular and is provided at a top side of a peripheral edge with a projection ( 13 ) which extends away from said housing. 
     
     
         12 . Method for driving a water-displacement vessel ( 1 ) comprising a hull with a longitudinal axis ( 15 ), comprising a bottom and comprising a pod drive ( 2 ) arranged close to the bottom, said pod drive ( 2 ) being provided with a housing ( 4 ) containing a propeller shaft ( 5 ) which protrudes through the housing and to which propeller shaft ( 5 ) a propeller is attached at a propeller end, and a drive for said propeller shaft, which propeller shaft ( 5 ) defines a first axis ( 7 ), which housing ( 4 ) is rotatable with respect to the hull between a rearward position and a forward position about a rotation shaft ( 9 ,  29 ) which defines a second axis ( 12 ,  32 ) which is not vertical and forms an angle (α) of 40°-90°, preferably between 60°-80°, with the first axis, wherein an annular jet pipe ( 17 ) is arranged around the propeller, comprising a peripheral edge ( 11 ) which is at a distance from the propeller shaft, wherein the method comprises the following steps:
 rotating the housing about the rotation shaft into the forward position, and 
 adjusting the direction of rotation of the propeller so that the jet pipe has a water-suction effect and the vessel is driven. 
 
     
     
         13 . Method according to  claim 12 , wherein, after a predetermined speed has been reached, the housing is rotated about the rotation shaft ( 9 ,  29 ) into the rearward position, with reversal of the direction of rotation of the propeller. 
     
     
         14 . Method according to  claim 12 , wherein the vessel is provided with at least two pod drives ( 2 ), wherein at least one pod drive is situated in the forward position, and the other pod drive is situated in the rearward position. 
     
     
         15 . Method according to  claim 12 , wherein the vessel is substantially unladen. 
     
     
         16 . Method according to  claim 13 , wherein the vessel is provided with at least two pod drives ( 2 ), wherein at least one pod drive is situated in the forward position, and the other pod drive is situated in the rearward position. 
     
     
         17 . Water-displacement vessel according to  claim 2 , wherein the first axis ( 7 ) is substantially parallel to the longitudinal axis ( 15 ) in the rearward position. 
     
     
         18 . Water-displacement vessel according to  claim 2 , wherein the pod is designed, in the case of a low degree of loading, to drive the vessel in the forward position by means of suction and, after a predetermined speed has been reached, to rotate about the rotation shaft ( 9 ,  29 ) into the rearward position, with reversal of the direction of rotation of the propeller. 
     
     
         19 . Water-displacement vessel according to  claim 2 , wherein the second axis ( 12 ,  32 ) forms an angle (β) of 5-30° with the vertical in the position of use. 
     
     
         20 . Water-displacement vessel according to  claim 9 , wherein the second axes ( 12 ) are not in a plane parallel to said central longitudinal plane.