Abstract: A multiple hull boat is disclosed including a pair of elongate, generally parallel hull members and a collapsible and expandable apparatus for connecting the hull members. There is a central deck section located generally above and between the hull members and having a pair of side edges that extend generally longitudinally of the respective hull members. First and second deck extension sections are mounted to respective hull members and the central deck section is supported relative to the deck extension sections for transverse movement relative to at least the first deck extension section. The hull members are selectively moveable apart such that the deck extension sections are extended at least partly beyond the respective side edges of the central deck section to expand the boat and are moveable together such that at least the first deck extension section is retracted at least partly within a respective side edge of the central deck section to collapse the boat.