A monohull offshore drilling vessel includes a hull having a moonpool; a multiple firing line hoist system mounted on the hull at the moonpool and including a mast having a top side and a base connected to the hull, wherein the mast has a hollow construction with a first side and an opposed second side; a first hoisting device having load attachment means displaceable along a first firing line extending on the outside of and adjacent to the first side of the mast; a second hoisting device having load attachment means displaceable along a second firing line, which on the outside of and adjacent to the second side of the mast; wherein the first and second hoisting devices each include cable(s) and associated winch(es), the winches disposed in the hollow construction of the mast, to manipulate the position of each of the load attachment devices relative to the mast.

A moon pool control device (5) for a marine vessel (1) comprises one or more closure members (8a,b) arranged for movement in the moon pool, between a moon pool closing position in a region of the moon pool opening (7), a moon pool open position, and a retracted position, and guiding means (14a,b; 15a,b; 17a,b; 18a,b) and motive means (9a,b; 10a,b; 22) configured for moving the closure member between said positions. In a particular embodiment, a pair of closure members (8a,b) and corresponding guiding means (14a,b; 15a,b; 17a,b; 18a,b) and motive means (9a,b; 10a,b; 22) are arranged on opposite lateral sides of the moon pool and configured to cooperate to close the opening (7) when both closure member s are in the closing position. The closure members comprise a continuous surface that forms a fluid barrier. The closure members may be retrieved onto the deck of the vessel.

Provided is a locking apparatus for a damping device of a moonpool, which can automatically lock and unlock an opened state of the damping device of the moonpool. The locking apparatus includes: one or more first locking members installed in a sidewall of the moonpool; one or more second locking members installed in a side of the damping device; and a holding unit separably holding the first locking members and the second locking members when the damping devices are in the opened state.

The invention relates to a monohull drillship (1), comprising an elongated hull (2) extending in the length direction (3) of the drillship. Said hull (2) is provided with at least one open moon pool (4) arranged to be located at the waterline (5) during use of the drillship. The drillship (1) is arranged for multiple-activity operations, e.g. simultaneous drilling and casing handling, in such a manner that drilling equipment can be passed through said at least one moon pool (4) at at least two locations (7, 8), i.e. at at least two so-called well centres, which are spaced apart from each other in at least a direction (6) substantially transverse to the length direction (3) of the hull of the drillship.

Embodiments relate generally to a turret system for use in a floating vessel. The turret system may comprise a turret body and windlass subsystem. The turret system may comprise top and bottom surfaces, first and second mooring line storage sections, and first and second mooring line channel sections. Each mooring line storage section may include an opening and cavity. Each opening is operable to receive a mooring line. The first and second mooring line channel sections may be separate elongated passageways for first and second mooring lines, respectively, to be directed through the turret body and an exterior of the floating vessel without coming into contact with one another. The windlass subsystem may comprise a rotatable member, and configured to be transportable between locations. When the windlass assembly is configured to be secured to the turret body, the windlass assembly is configurable to control a movement of a mooring line.

The invention provides a system for operating a drilling rig on a drilling vessel, the system comprising a drilling tower (2) having at least two segments (4, 5), a first segment (4) is fixedly connected to the drilling vessel (1), a second segment (5) is connected to the first segment (4), said second segment (5) is adapted to move longitudinally relative the first segment (4) by raising and lowering means. A tool (8) is suspended from at least one wire (16), said at least one wire (16) is extending over at least one sheave (7a, 7b) on top of the second segment (5), said at least one wire (16) is coupled to with a passive compensator arrangement (20) and a winch (14), said passive compensator (20) is connected to the winch (14).

The present invention relates to a method for riser string handling on an offshore drilling vessel (1), the offshore drilling vessel comprising a multiple firing line hoist system, a riser tensioner system (50) arranged in the second firing line, and a suspended riser transfer device (60). The method comprising the steps of lowering a riser string in the first firing line, and simultaneously assembling and preparing a riser tensioner system in the second firing line, wherein the riser hang-off assembly displaces the riser string, leaving the top end of the riser string exposed, from the first firing line to the second firing line to be connected to the riser tensioner system.

Embodiments relate generally to a turret system for use in an FPSO vessel. The turret system may comprise a turret body and windlass subsystem. The turret system may comprise a top and bottom surface, first and second mooring line storage sections, and first and second mooring line channel sections. Each mooring line storage section may include an opening and cavity. Each opening is operable to receive a mooring line. Each mooring line channel section may be an elongated passageway for a mooring line to pass between an exterior of the FPSO vessel and a mooring line storage section. The windlass subsystem may comprise a rotatable member, and configured to be transportable between a plurality of locations. When the windlass assembly is configured to be secured to the turret body, the windlass assembly is configurable to control a movement of a mooring line.

An offshore drilling vessel includes a main deck, a moonpool a firing line hoist system having a tower, a BOP transport system and a pivotally supported U-shaped working deck. The U-shaped working deck can be pivoted between an active position, in which it extends in a substantially horizontal direction such that it covers a portion of the moonpool, and a non-active position, in which it extends in a substantially vertical direction such that it provides room for a BOP to be moved by the BOP transport system from a storage position adjacent the moonpool into a launch position above the moonpool, in which launch position the BOP is located between the tower and the working deck.

A method for riser string handling on an offshore drilling vessel, the offshore drilling vessel including a multiple firing line hoist system, a riser tensioner system arranged in the second firing line, and a suspended riser transfer device. The method including the steps of lowering a riser string in the first firing line, and simultaneously assembling and preparing a riser tensioner system in the second firing line, wherein the riser hang-off assembly displaces the riser string, leaving the top end of the riser string exposed, from the first firing line to the second firing line to be connected to the riser tensioner system.