Supporting Hull Structure
Supporting hull structure means that part of the ship structure on/in which the shipboardfitting is placed and which is directly submitted to the forces exerted on the shipboard fitting. The hull structure supporting capstans, winches, etc. used for the normal towing and mooring operations mentioned above should also be subject to this guidance.
Source: IMO MSC.1/Circ.1175, guidance on shipboard towing and mooring equipment, 24 May 2004, International Maritime Organization. Regulatory Guidance