This happened a year of two back so although you may have seen this before is too good to leave languishing in cyberspace. Many thanks to Andy Rankine for editing this down.
This exercise was pre-arranged I believe. The helicopter crew would have initially briefed the skipper about what is going to happen and what direction to sail etc. The pilot often requires the yacht to sail on a close reach while the crewman is lowered down on the winch. The helm’s role is critical and they need to avoid looking up at the aircraft or otherwise being distracted. Note the level of noise. It is extremely hard to communicate on board with a helicopter hovering over your heads.