Well i vaguely remember one drunken "Obby Oss " day back in the early seventies about fifty of us deciding it would be a good idea to go for a swim from it....
and I suspect the tide was in. /forums/images/graemlins/smile.gif I bet you wouldn't want to swim in there if you saw the black thick mud on the bottom.
I think the gate only went in about 1990. I've dried out (not booze) back in the eighties.