What spurred me to devise a solution was when a fellow sailor was trying to return some borrowed items and found I was not on board. It took him only a few seconds to work out how to lower the passerelle. He then walked around and poked the items through a partially opened hatch. All this was in broad daylight: his access was unfettered and unchallenged. I knew this person, but it was still an unnerving experience when I returned to find someone had been on my boat without my permission.