Surprisingly, only just come across this thread. One of our tasks at Thorney was to do trials with the Littlehampton lifeboat to allow a team from Farnborough to take measurements of helo static discharges. Chatting with the team afterwards and they mentioned figures in the range of 160,000 -180,000 volts (low current, of course !) Water/deck/land contact, when winching, was made less painful by keeping hands off the cable. On one notable occasion, I forgot to do so at the end of a particularly strenuous wet winching session in Holyhead harbour. I was winched onto the Marine Unit's pinnace and touched down with hand on the wire and mouth open, breathing hard. I have a 'collection' of amalgam molars, upper and lower and the inevitable static discharged across them - the taste, and smell, remained for several hours !