Ice floes in North Sea. Ice floes are still menacing fishing fleets and colliers in the North Sea. The Royal Navy's Fishing Protection Patrol is constantly on the watch in the shipping lane, and additional job to their routine patrol protecting the fishing grounds from 'poachers'. Photo shows, two of the crew of HMS Mariner, which reached Hull last night, braving the icy conditions as the ship forces its way through an ice floe in the North Sea. 3 March 1947