When two of us are sailing offshore and taking turns at the helm and sleeping, the one on watch wears a safety harness and is tethered to the boat; we also have a swim ladder that can be deployed from in the water; also we trail a yellow nylon ski rope so hopefully if a person falls overboard, he can grab it as it goes by (nylon so it floats and won't foul the rudder or prop). We also have walkie talkies on so the guy at the helm can yell to the one below as needed! Sounds like overkill but one of us seems to take an unintentional swim on occasion