A method for constructing a hull of an offshore structure includes (a) welding a plurality of plates together to form a plate assembly. The method also includes (b) passing the plate assembly through a rolling machine with the plate assembly in a vertical orientation. In addition, the method includes (c) bending the plate assembly into a cylinder during (b). The cylinder includes a pair of circumferentially adjacent free ends. Further, the method includes (d) welding the free ends of the cylinder together after (c) to form a cylindrical external wall.

A cockpit extension that extends aft of a boat transom for increasing the afterdeck area of the boat. The cockpit extension includes a deck that can be accessed from the afterdeck of the boat and an under-face beneath the deck that can be above or below the water-line of the boat. The cockpit extension can also include one or more of a gunwale, inner bulkhead, and outer freeboard. A running surface can also be provided on the under-face that improves the backing down process of the boat. The boat has at least two outboard engines, attached on the port and starboard sides of the boat transom, respectively.

A cockpit extension that extends aft of a boat transom for increasing the afterdeck area of the boat. The cockpit extension includes a deck that can be accessed from the afterdeck of the boat and an under-face beneath the deck that can be above or below the water-line of the boat. The cockpit extension can also include one or more of a gunwale, inner bulkhead, and outer freeboard. A running surface can also be provided on the under-face that improves the backing down process of the boat. The boat has at least two outboard engines, attached on the port and starboard sides of the boat transom, respectively.

A modular compartment bulkhead assembly is provided that includes a first external body, a bulkhead, and a second external body. The first external body segment may include a first end portion. The first end portion may be coupled to an external seal body and the external seal body may include a first internal channel. The bulkhead may include an internal seal body. The internal seal body may be configured to be inserted into the first internal channel of the external seal body to form an internal seal between the bulkhead and the first external body segment. The second external body segment may include a second end portion. The second end portion may include a second internal channel, and the external seal body may be configured to be inserted into the second internal channel to form an external seal between the external seal body and the second external body segment.

A cockpit extension extends aft between port and starboard outboard engines mounted on a tri-pontoon boat transom for increasing the usable afterdeck area of the boat. The cockpit extension includes a topside deck that can be accessed from the afterdeck of the boat and an under-face beneath the topside deck that can be above or below the water-line of the boat. A lower surface of the under-face can be configured to improve the backing down characteristics of the boat.

A cockpit extension extends aft between port and starboard outboard engines mounted on a tri-pontoon boat transom for increasing the usable afterdeck area of the boat. The cockpit extension includes a topside deck that can be accessed from the afterdeck of the boat and an under-face beneath the topside deck that can be above or below the water-line of the boat. A lower surface of the under-face can be configured to improve the backing down characteristics of the boat.

A jet propulsion device is mounted to a vessel body and connected to a drive shaft. A bearing rotatably supports the drive shaft. A bulkhead is disposed inside the vessel body and below a deck. The bulkhead supports the bearing and includes a gap disposed between the drive shaft and the deck. The drive shaft and the gap overlap as seen in a vertical direction.

A firestop system for fire stopping a bus duct that passes through an opening in a marine deck or a marine bulkhead includes a boot seal wrapped around the bus duct housing. The boot seal has a top end attached to the bus duct, and a bottom end attached to the division. The boot seal is made of flexible material to allow for movement of the bus duct relative to the division due to vibration. The boot seal may be made of a thermal barrier wrap or other high-temperature insulating mat materials to allow heat generated under normal condition to escape while providing firestopping and temperature resistance under fire exposure conditions. The firestop system may also have a gasket positioned between the bus duct and the boot seal to accommodate irregularities in the outside surface of the bus duct housing.

A cockpit extension extends aft between port and starboard outboard engines mounted on a tri-pontoon boat transom for increasing the usable afterdeck area of the boat. The cockpit extension includes a topside deck that can be accessed from the afterdeck of the boat and an under-face beneath the topside deck that can be above or below the water-line of the boat. A lower surface of the under-face can be configured to improve the backing down characteristics of the boat.

A cockpit extension that extends aft of a boat transom for increasing the afterdeck area of the boat. The cockpit extension includes a deck that can be accessed from the afterdeck of the boat and an under-face beneath the deck that can be above or below the water-line of the boat. The cockpit extension can also include one or more of a gunwale, inner bulkhead, and outer freeboard. A running surface can also be provided on the under-face that improves the backing down process of the boat. The boat has at least two outboard engines, attached on the port and starboard sides of the boat transom, respectively.