SECURITY BOOM 

A security boom is in use between 'A' Head (36°08·04N 5°21·85W) and Gun Wharf (36°07·97N 5°21·38W). The boom is closed during visits to His Majesty’s Naval Base Gibraltar, but a gap is available for small craft adjacent to Gun Wharf. When not in use the gap is in the centre of the harbour. The boom is marked by yellow buoys. All vessels are advised to keep well clear unless directed by Gibraltar VTS or King's Harbour Master.