Systems, Apparatuses, and Methods for Removal and Insertion of Thrusters using a Transfer System

Abstract

Embodiments of the present disclosure include apparatuses and methods for the underwater removal and insertion of thrusters using a transfer system. Embodiments include a transfer system having a deck fitting assembly configured to be mounted to a hull of a marine vessel, a tension rod assembly secured to the deck fitting assembly, a track system secured to the tension rod assembly, a transfer frame movably secured to the track system via a hoist system, and a cradle removably secured to the transfer frame. Cradle and transfer frame are vertically movable and horizontally traversable along a portion of the hull via the hoist system.

What is claimed is: 
     
         1 . A transfer system, comprising:
 a deck fitting assembly configured to be mounted to a hull;   a tension rod assembly secured to the deck fitting assembly;   a track system secured to the tension rod assembly;   a transfer frame movably secured to the track system via a hoist system; and   a cradle removably secured to the transfer frame,   wherein the cradle and transfer frame are vertically movable and horizontally traversable along the track system.   
     
     
         2 . The system of  claim 1 , wherein the tension rod assembly includes three tension rods removably secured to each other. 
     
     
         3 . The system of  claim 1 , wherein the track system is attached to the hull. 
     
     
         4 . The system of  claim 3 , wherein the track system is substantially horizontal and parallel to a deck surface of the hull. 
     
     
         5 . The system of  claim 4 , wherein the track system includes a beam track assembly having two longitudinal I-beams connected together via I-beam stiffeners, a gusset plate installed on top of each I-beam, and a hoist rack installed under each I-beam. 
     
     
         6 . The system of  claim 5 , wherein the hoist system is movably attached to the hoist rack at a first end and to the transfer frame at a second end. 
     
     
         7 . The system of  claim 6 , wherein the hoist system includes a drive motor configured to move the cradle and transfer frame along the track system, and a lifting motor configured to raise and lower the cradle and transfer frame. 
     
     
         8 . The system of  claim 1 , wherein the cradle is removable via a crane or other lifting device. 
     
     
         9 . The system of  claim 1 , wherein the cradle is configured to securely enclose a thruster. 
     
     
         10 . The system of  claim 9 , wherein the thruster is a retractable demountable thruster. 
     
     
         11 . The system of  claim 10 , wherein the thruster is an azimuth or azimuthing thruster. 
     
     
         12 . The system of  claim 1 , wherein the deck fitting assembly includes a deck block mounted on a deck plate and a support flange installed onto the deck block. 
     
     
         13 . The system of  claim 1 , further comprising a sensor cable and load sensor pin attached to the tension rod assembly, the sensor cable and load sensor pin configured to measure and perform load readings of any load supported by the tension rod assembly. 
     
     
         14 . The system of  claim 5 , further comprising a hydraulic pre-tensioning ram attached to the tension rod assembly, the ram configured to apply a simultaneous pre-load to each I-beam, thereby securing the system in place during operation. 
     
     
         15 . The system of  claim 7 , wherein the hoist rack includes teeth equally spaced along the rack, the teeth configured to interact with a pinion gear of the drive motor and assist the hoist system in moving the cradle and transfer frame along the track system. 
     
     
         16 . The system of  claim 15 , wherein the attachment at the first end includes multiple first structural plates positioned on either side of each I-beam and secured together via rods, and the attachment at the second end includes a lifting block structure having multiple second structural plates attached to at least one of a block and pin type and hook type arrangement. 
     
     
         17 . The system of  claim 16 , wherein the hoist system includes chain link structures that wrap around and mesh with sprockets located within first and second structural plates and are tied to the lifting motor to assist the lifting motor in raising and lowering the lifting block structure. 
     
     
         18 . The system of  claim 17 , wherein the hoist system is driven via at least one of pneumatic, hydraulic, and electric power. 
     
     
         19 . The system of  claim 8 , wherein the cradle includes padeye-flange connections having apertures. 
     
     
         20 . The system of  claim 19 , wherein the cradle includes kort nozzle saddle plates positioned internally within the cradle such that an outer surface of a thruster kort nozzle rests on the kort nozzle saddle plates, and a gear case saddle plate positioned internally within the cradle such that an outer surface of a thruster gear box rests on the gear box saddle plate. 
     
     
         21 . A method for removing a thruster from a hull, comprising:
 mounting a deck fitting assembly to the hull, wherein a tension rod assembly is secured to the deck fitting assembly, a track system is secured to the tension rod assembly, and a transfer frame is movably secured to the track system via a hoist system;   lowering and removably securing a cradle to the transfer frame, wherein the cradle and transfer frame are vertically movable and horizontally traversable along the track system;   moving the cradle and transfer frame across the track system to a position directly under an opening in the hull via the hoist system;   raising the cradle and transfer frame towards the opening via the hoist system;   lowering the thruster from inside the hull through the opening and into the cradle;   lowering the cradle, transfer frame, and enclosed thruster away from the opening via the hoist system;   moving the cradle, transfer frame, and enclosed thruster across the track system towards an end of the track system; and   removing at least one of the cradle and enclosed thruster.   
     
     
         22 . The method of  claim 21 , wherein the cradle and enclosed thruster are removed via a crane or other lifting device. 
     
     
         23 . The method of  claim 21 , further comprising removing and replacing at least one of the enclosed thruster and a new thruster. 
     
     
         24 . The method of  claim 23 , wherein the track system includes a beam track assembly having two longitudinal I-beams connected together via I-beam stiffeners, a gusset plate installed on top of each I-beam, and a hoist rack installed under each I-beam. 
     
     
         25 . The method of  claim 24 , wherein the hoist system is movably attached to the hoist rack. 
     
     
         26 . The method of  claim 25 , wherein the hoist system includes a drive motor configured to move the cradle and transfer frame along the track system, and a lifting motor configured to raise and lower the cradle and transfer frame.