Yesterday there was an announcement by our cruise ship captain saying that we’d received a mayday signal and we were changing course to assist. The distress call had come from a yacht that was visible slightly to port about half an hour later. The boat was bobbing madly in the waves, without sails and apparently out of power, towing a damaged dingy and with a fluorescent life-vest hoisted on the main mast for extra visibility. It had taken a hawk-eyed bridge officer with binoculars to even find them, and that was after the diligent crew had accidentally come across a crackled SOS radio signal in the first place. On a clear day, you’d be lucky to radio a short distance of ten or fifteen nautical miles, probably a little further than can be seen with binoculars.