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.

A watercraft has a hull having a keel, a deck supported by the hull, and a compartment defined between the hull and the deck. A fuel reservoir is disposed in the compartment and extends longitudinally over the keel. The fuel reservoir has an external hollowed portion. At least one battery is at least partially disposed in the external hollowed portion.

A watercraft has a hull having a keel, a deck supported by the hull, and a compartment defined between the hull and the deck. A fuel reservoir is disposed in the compartment and extends longitudinally over the keel. The fuel reservoir has an external hollowed portion. At least one battery is at least partially disposed in the external hollowed portion.

A boat includes a compartment and a stowable seat. The stowable seat includes a stowable seat bottom movable between a stowed position and a raised position. In the stowed position, the stowable seat bottom is located in the compartment. In the raised position, the stowable seat bottom can be located laterally between a first seat and a second seat and at a level higher than a floor of the boat. The stowable seat can include a stowable seat frame having a static support and a pivot arm. The upper end of the pivot arm can be pivotably connected to the stowable seat bottom. The stowable seat bottom can include a slider engaged with a slot of the static support to slide within the slot as the stowable seat bottom moves between the stowed position and the raised position.

A boat includes a compartment and a stowable seat. The stowable seat includes a stowable seat bottom movable between a stowed position and a raised position. In the stowed position, the stowable seat bottom is located in the compartment. In the raised position, the stowable seat bottom can be located laterally between a first seat and a second seat and at a level higher than a floor of the boat. The stowable seat can include a stowable seat frame having a static support and a pivot arm. The upper end of the pivot arm can be pivotably connected to the stowable seat bottom. The stowable seat bottom can include a slider engaged with a slot of the static support to slide within the slot as the stowable seat bottom moves between the stowed position and the raised position.