A sealing arrangement is used when mounting a thruster in a well box attached to a hull of a marine vessel. The well box has an axis, a bottom flange, a top flange, an annular wall therebetween and hoisting pipes fastened parallel with the axis to the bottom flange radially outside the annular wall. Both the well box and a mounting flange have at least one surface acting as a sealing surface between the well box and the thruster. At least one of the surfaces has a groove for a seal for preventing water from entering the well box. The well box has a rotationally symmetric wall with an internal guide surface and the mounting flange of the thruster has an axially extending rotationally symmetric part provided with an outer surface having means for sealing the mounting flange in relation to the well box.

The present disclosure relates to a guiding arrangement for a retractable thruster assembly. The guiding arrangement may comprise a foundation plate, a first upper guide, a second upper guide, a first lower guide, and a second lower guide. The first lower guide and the second upper guide may be arranged such that an arc angle within the range from 25 to 75 is confined therebetween. Thus, flexibility regarding the implementation of the retractable thruster assembly as L-drive or Z-drive may be gained.

A sealing arrangement is used when mounting a thruster in a well box attached to a hull of a marine vessel. The well box has an axis, a bottom flange, a top flange, an annular wall therebetween and hoisting pipes fastened parallel with the axis to the bottom flange radially outside the annular wall. Both the well box and a mounting flange have at least one surface acting as a sealing surface between the well box and the thruster. At least one of the surfaces has a groove for a seal for preventing water from entering the well box. The well box has a rotationally symmetric wall with an internal guide surface and the mounting flange of the thruster has an axially extending rotationally symmetric part provided with an outer surface having means for sealing the mounting flange in relation to the well box.

A method for disassembling and/or assembling an underwater section of a retractable thruster unit of a swimming vessel. A supporting cradle is detachably fixed to the underwater section from below, and the thruster unit is lifted so that the underwater section is at least partly brought inside the well formed in the bottom of the vessel. Lifting wires of an auxiliary lift are connected to the supporting cradle for supporting the thruster unit. Water is drained from the well, and the lower gear is disengaged and the intermediate section and the lower gear are sealed. After that water is let to ingress into the well and the underwater section is lowered down by the auxiliary lift to dock bottom or sea bed, from where the underwater section is picked up with a crane.

An isolation method, and apparatus, for isolating and temporarily sealing closed an opening of a marine vessel to prevent ingress of fluid into or through the opening, sealing an internal side of the opening from an external side of the opening. A positioning line is provided between a connection point and the sealing apparatus, with the positioning line being tensioned to pull the sealing apparatus towards the opening. The method is performed entirely diverlessly, with no personnel required in or under the water at any stage of the method, including during connecting the positioning line to the connection point and pulling the sealing apparatus onto and/or into the opening.

A propulsion assembly of a ship or floating platform includes a housing within a hull or platform. The housing is watertight except for an opening external to the hull. A stationary motor is arranged in the hull external to the housing. A thruster is external to the hull to generate thrust on the ship or floating platform. A telescopic driving shaft passes sealingly through a housing wall to connect the motor and the thruster and to transmit movement from the motor to the thruster. The thruster retracts within the housing through the opening. A separate submersible movable hatch is disconnectable from the thruster and the housing and passes externally to the hull, and seals the opening to form a watertight closed chamber. A fluid evacuation device evacuates fluid within the closed chamber so the thruster, when retracted in the housing and closed by the hatch, forms the closed chamber.

Provided is a pod propulsion system including first and second counter rotating propellers for propelling a marine vessel first and second propeller modules, each including an electric motor having a driving-end configured to rotate the first and second propellers, respectively. Also included are first and second gondolas, each (i) for housing a respective one of the first and second electric motors and (ii) including a boltable interface formed along a lengthwise direction of an extremity of the gondola. A strut (i) connects the first and second gondolas to a hull of the marine vessel (ii) including first and second boltable interfaces. Each of the boltable interfaces of the strut is configured to form a bolted joint interface with a corresponding one of boltable interfaces of the first and second gondolas.