A compressed air tank for sinking prevention comprises a compressed air tank having a valve; and an air pocket coupled to the compressed air tank and being filled with air discharged from the compressed air tank when the valve is opened, wherein buoyancy is provided to a cabin that is being flooded through the air pocket to prevent a ship from foundering.

Security barrier comprising: a substantially planar support element (2) having top and bottom edges, wherein respective top and bottom first attachment sites are formed at the top and bottom edges; and a bulbous barrier element (9), which is separate from the support element, having top and a bottom edges and respective top and bottom second attachment sites formed at the top and bottom edges, with a curved protruding section extending between the top and bottom edges, the protruding section extending away from the plane containing the top and bottom edges, wherein the support element and the barrier element are releasably connected to each other by way of the first and second top and bottom attachment sites, so that the support element and barrier element define an internal space therebetween which receives a horizontal rail, and wherein the security barrier may rest on the rail, a vertical plane being defined between the rail and the surface, so that the rail lies at or near the top edge of the support element and of the barrier element, the support element extends close to the vertical plane, and the protruding section protrudes outwardly from the vertical plane.

A wall for a watercraft and the watercraft. The watercraft having a hull and a deck supported by the hull. The wall extends around at least a portion of a floor of the deck. The wall includes a rear wall, a front wall, and two sidewalls connecting the rear wall and the front wall. The front wall has a first wall section, a second wall section and an intermediate wall section extending between the first and second wall sections. The first wall section includes a first door while the second wall section includes a second door. The first and second doors are moveable between an opened position and a closed position. The watercraft further includes a seat connected to the deck. The seat is positioned proximate to and aligns with at least one of the first and the second doors.