-Although it is not too unique, I always bring a small roll of fluorescent orange masking tape and hang a length of it on those banger sites on the boat. Normally shortening it as everyone learns the correct paths. Can also be used on dinghy, etc.
-A bit more unique may be the bright yellow crime scene tape, which normally serves to memorialize a crew faux pas that shouldn't have occurred. This is applied only at the captain's discretion, as some crew may have a tendency to overuse it, and there would soon be no heads available... YMMV
.
