Clasp System

I saw an ingenious bracelet clasp one time that was hand made. I
can’t quite picture it now but the wearer of the bracelet showed it
to me and told me that the clasp idea had come from something
commonly used on a boat. A part of it could pop up and catch onto
another part and then be pushed down to secure it. It was so clever
and not like anything I’d seen before although it seemed somewhat
complicated. I don’t know any more than that but I wish I could see
it again to try to make something similar. Are any of you familiar
with boats and know what this might be? Annette