Hull of a tugboat and tugboat comprising said improved hull

Abstract

A hull of a tugboat for towing/assisting a vessel is described The hull has a bottom, a bow, a stern, an underbody provided with a first keel and a second keel, the first keel being parallel to and facing the second keel, first thruster means and second thruster means. A tugboat with such hull is also described.

1 . A tunnel-hull of a tugboat for towing/assisting a vessel, said tunnel-hull having a water plane, a base line, a main section, as well as a longitudinal axis dividing said tunnel-hull in a first lateral part and a second lateral part, said tunnel-hull comprising a bottom, a bow, a stern, and further comprising:
 an underbody, said underbody comprising a first keel and a second keel, wherein said first keel is parallel to and faces said second keel,   first thruster means and second thruster means,   wherein each keel is arranged on a respective side of said underbody, in a substantially central position, and is connected to said underbody respectively in correspondence of the bow and the stern of said tunnel-hull, said two keels extending in depth perpendicularly or in a substantially perpendicular manner so as to have a draft equal to or greater than that of said first and second thruster means, and wherein said first thruster means and said second thruster means are positioned respectively at the bow and stern of the tunnel-hull, and are substantially aligned along said longitudinal axis of said tunnel-hull;   wherein   said two keels are integral with said tunnel-hull and are configured in such a way that they form a tunnel with at least a portion of said bottom of said tunnel-hull,   and   said tunnel-hull has a longitudinal section having a concave bow portion, a concave stern portion and a convex intermediate portion, positioned between said bow portion and said stern portion, and has a first concave bottom portion which extends from said first thruster means to said main section, and a second concave bottom portion which extends from said second thruster means to said main section; said two concave bottom portions being substantially symmetrical with respect to said main section; each concave bottom portion comprising a respective first portion, externally to said tunnel, which extends from the respective thruster means to the keels, and a second portion, internal to said tunnel, which extends from the keels to the main section, said first and second thruster means being arranged in said first portion, externally to said tunnel, of a respective concave bottom portion, so that, when a water flow is generated by said first thruster means or by said second thruster means, said water flow is channeled within said tunnel, following a respective concave bottom portion, and only a minimal amount of water of said water flow reaches respectively said second thruster means or said first thruster means.   
     
     
         2 . The tunnel-hull according to  claim 1 , wherein said two keels are in a position shifted toward the bow of said tunnel-hull. 
     
     
         3 . The tunnel-hull according to  claim 1 , wherein said first thruster means and said second thruster means have a respective center and in that said first thruster means and said second thruster means are arranged such that said base line of said tunnel-hull passes from each center or above each center. 
     
     
         4 . The tunnel-hull according to  claim 1 , further comprising a fin centrally arranged on the bottom of said tunnel-hull, at the stern of the tunnel-hull itself; said fin being preferably integral with said tunnel-hull. 
     
     
         5 . The tunnel-hull according to  claim 1 , further comprising a first pushing fender and a second pushing fender, each of which is externally arranged to the tunnel-hull, on a respective lateral part, so as to be below said water plane. 
     
     
         6 . The tunnel-hull according to  claim 5 , wherein said pushing fenders are positioned on the tunnel-hull so as to be in correspondence with said base line of said tunnel-hull. 
     
     
         7 . The tunnel-hull according to  claim 1 , further comprising a third pushing fender, arranged externally to the tunnel-hull so as to be above said water plane. 
     
     
         8 . The tunnel-hull according to  claim 1 , wherein said first thruster means and said second thruster means comprise respectively at least one azimuth propulsor. 
     
     
         9 . Tugboat for towing/assisting a vessel, the tugboat comprising the tunnel-hull according to  claim 1 , wherein said first thruster means are driven by a first engine, said first engine being positioned at the bow of said tunnel-hull and connected to said first thruster means by a first shaft, and in that said second thruster means are driven by a second engine, said second engine being positioned at the stern of said tunnel-hull and connected to said second thruster means by a second shaft; said engines having a respective longitudinal axis and being arranged within the tunnel-hull, in a respective lateral part of it, in such a way that the longitudinal axis of each engine forms with the longitudinal axis of said tunnel-hull a respective angle. 
     
     
         10 . The tugboat according  claim 9 , wherein the value of each angle is between 0° and 90°. 
     
     
         11 . The tugboat according to  claim 9 , wherein said longitudinal axes of said motors are parallel and said angles are equal. 
     
     
         12 . The tugboat according to  claim 9 , further comprising a winch arranged at the bow of said tunnel-hull, in the proximity or in correspondence of said first thruster means, and/or a winch arranged at the stern of said tunnel-hull, in proximity or in correspondence of said second thruster means, a respective tow cable being wind/unwind on each winch in such a way that the force for towing/assisting said vessel, exerted by a winch at the bow or stern, is applied on a respective point of said bow or said stern. 
     
     
         13 . The tugboat according to  claim 12 ,
 further comprising a central control bridge and at least one corresponding chock for each winch, in such a way that:   said winch is arranged between said control bridge and said bow, and the corresponding chock is arranged between said winch and said bow; and/or   said winch is arranged between said control bridge and said stern, and the corresponding chock is arranged between said winch and said stern.   
     
     
         14 . The tugboat according to  claim 13 , wherein said engines are positioned externally to said control bridge; said control bridge preferably having a substantially circular section. 
     
     
         15 . The tugboat according to  claim 9 , further comprising an engine room; said engine room comprising said two engines. 
     
     
         16 . The tugboat according to  claim 9 , further comprising two engine rooms, each of which is respectively arranged at bow and stern of said tunnel-hull and comprises a respective engine. 
     
     
         17 . The tugboat according to  claim 9 , further comprising steering and controlling means for steering and controlling said first and second thruster means, said steering and controlling means being aligned along an axis which coincides with said longitudinal axis.