Abstract: A suspension system for a vessel with at least one left hull, at least one right hull and a chassis, the suspension system including respective front left, front right, back left and back right support rams connected between the chassis and the respective hull and including a respective compression chamber which with a respective diagonal conduit forms a respective support compression volume; first digonal support interconnection valve (59) selectively interconnects front left and back right diagonal conduits (61, 64) and support compression volumes second diagonal support interconnection valve (60) selectively interconnects front right and back left diagonal conduits (62, 63) and support compression volumes, a deck attitude control system (100) comprising a controller (102), sensors, first and second diagonal actuating arrangements (25, 26) for controlling fluid flow across the respective diagonal support interconnection valve to control a position of a point on the chassis relative to a reference (5).

Abstract: A suspension system for a vessel (1) having at least one left hull (11), at least one right hull (12) and a chassis portion (10), the suspension system including supports (20) for at least partially supporting the chassis portion relative to the left and right hulls, and a front left and back left damping ram (31, 33) connected between the chassis portion and longitudinally spaced points on the at least one left hull, a front right and back right damping ram (32, 34) connected between the chassis portion and longitudinally spaced points on the at least one right hull. The suspension system further includes a deck attitude control system (250) comprising a controller (252), sensors, and a respective actuator arrangement for each of at least two orthogonally spaced damper rams. The actuators control a position of at least one point on the chassis relative to at least one reference.