Abstract: A system for firmly fastening together two or more independently buoyant sections of a multiple sectioned boat along interfacing bulkheads above the waterline, and at least one matable fastener disposed near or below the waterline on each of the interfacing bulkheads. The lower fastener includes a projecting member mounted in a watertight manner through one interfacing bulkhead of a particular hull section and a correspondingly shaped socket disposed through the opposing adjacent bulkhead that receives the projecting member.