Aft block (Block construction)

An aft block is one of the large pre-assembled hull sections, built around the stern, engine room, and steering gear, that is erected on the building dock during block (modular) construction. Modern shipbuilding fabricates the hull as numbered blocks: panels and sub-assemblies are welded into grand blocks ashore, outfitted with piping, machinery foundations, and cabling, then lifted and joined on the dock in an erection sequence. The aft block carries the most outfitting density because it holds the main engine, shafting, and stern frame, so its accuracy control and weld alignment at the erection butts set the shaft line. It is a construction term, not a coating or surface-preparation term.