Learning all the code flags is no longer a part of any yachting syllabus, but every watchkeeper must be aware of the meaning of flag ‘A’. It says, ‘I have a diver down. Keep well clear at slow speed.’ Sometimes these flags are made of plywood, sometimes of fabric, but they are always shown by dive boats. Watch out for them and comply with their request. If you miss one you could be responsible for causing a serious accident. Even if you don’t hurt anyone, you’ll get a well-deserved earful from the dive-boat cox’n.