Having sails up helps, but I was struck by the fact that when I rowed round Land's End and was two miles out at sea none of the 20 or so people running along on the cliff top saw me. What chance a ship two miles away closing at 20 knots? That's six minutes.
So I have been experimenting with an automatic identification system transceiver (apparently they call it a transponder but the experts say it is a technically a transceiver).
My WatchMate 850 receives and transmits from a VHF antenna fitted at the top of my mast. It can then identify if a ship is about to collide with me as well as telling all other large ships my whereabouts. It also provides a call sign for the ship so I can even radio them directly to warn them about PicoMicroYacht.
A byproduct is that PicoMicroYacht is being tracked and this then goes on the internet so people can know where I am (There is a pirate mode in case I want to receive but go in cognito).