My friend Neil tells me this is the perfect application for the bowline knot, temporary eye around a post. He says old wooden boats had two upright posts on the bow, like this bannister on our houseboat, strongest thing on the bow. Called 'em Samson Posts. Use to secure anchor or dock lines.
I tell him that's funny because I once knew a Samson Post back in the day. He played a little guitar down at The Temporary Eye, wore his hair long, liked to lift. Met a lady named Delilah, barber by trade, and it changed his life forever. Heard they tied the knot— a sheet bend, though some said it was a hitch or maybe square . . .
Slip knot, offered Neil, who'd obviously been there.