Abstract: Marine craft has a crushable frontal impact protection structure, comprising transverse bulkhead protecting passenger area; longitudinal crushable tubes; and transverse member. Webs and strengthen tubes, which may be made of extruded, heat treated aluminum; stainless steel; or plastic. Tubes in FIGS. 5 to 7 are splayed, to improve protection against angled impacts C. The forward ends of tubes are tapered, (FIG. 3) to initiate deformation. Tubes may be hexagonal, round, or oval in cross-section. FIG. 8 shows longitudinal bulkheads, and transverse bulkhead in place of tubes. FIG. 9 shows longitudinal corrugated sheets; these may be mounted transversely. FIG. 10 shows how area filled with deformable cellular foam, to act as a buoyancy aid if hull is breached. Side and roar impact protection is also disclosed.

Abstract: At least three beans, 2, 4, 6, are connected in at least two planes by means of a cruciform member 8. Rivets 30 are used to locate the joint while a bonding agent, which may be a structural adhesive or cold solder, sets. Cruciform arms 10 may be at ninety degree intervals; at least one arm may be deformed into, or extruded at, an alternative angle. The beams may be of aluminium; other metal; plastic, or composite material. More than one cruciform may be used in one joint (FIGS. 2, 3); arms 10 may be abbreviated to reduce the joint's bulk and mass. Plates 12, 14 may be used in opposition to a cruciform to strengthen and balance joints. The bonded joint may be used in the frame of a vehicle, particularly an amphibious vehicle. The cruciform member provides broad planar surfaces for a strong bonded joint, which is unlikely to peel.