Mock-up unit

A mock-up unit is a full-scale physical model of part of a ship, an engine room corner, a pump room, a galley, or a cabin, built in plywood, steel, or partial real components to rehearse piping and cabling routing, check access and maintenance clearances, and train the outfitting trades before the real space is built. It catches interferences and ergonomic problems that a drawing or even a 3D model can miss, and lets the owner sign off on layout early. Mock-ups are common for repeat series and for crowded, safety-critical spaces. The cost is justified when the same mistake repeated across a fleet would cost far more to fix afloat.