The Lossie rescue helicopter did a training exercise within sight of my home a few years ago. The sea was choppy. I watched an unfortunate guy in a survival suit struggle to get into a liferaft, then capsize. Then get in again. Eventually he stayed in, and was picked up by the winchman. Then, as he was being winched up, the two guys were lowered, and, I assume, the winchman dropped into the sea. A few swimstrokes and he was at the raft, in first attempt, and he stayed in no problem.