The Bulk of the insulation.

During the heat of the summer, our minds turned to the large expanses of bare metal in the living room. I welded plenty of brackets to the metal hull and the bulk head between the living room and the engine room. Steve battened them, and insulated them with our favourite Celotex. Whist the Bulkhead wasn't an exterior wall, now that winter has descended upon the Thames, the bulkhead insulation has made a noticable difference.