The pilot would operate the winch via a mirror
FED - IIRC 2 mirrors. Actually, they were (from memory) Hillman Husky hub caps, highly polished and and positioned such that the pilot could see what was going on below the aircraft by looking slightly right. When we started, that 'system' had been discarded and we relied on the winchman using a headset plugged into an auto-feed intercom reel. The junction between headset and intercom was less than 100% watertight and water entry was an ear-splitting experience!!
Wet winch training was slated for (what turned out to be) our last week as 'fill-ins'. Intention was to winch from a dinghy in the inner harbour. However, on arrival, we could see some local residents - sharks and ray circling - 'jungle' drums having advertised the prospect of a free lunch, maybe, so discretion ... etc.