An old retired sailor puts on his old uniform and heads to the docks once more for old times' sake.
He engages a prostitute and takes her up to a room.
He's soon going at it as well as he can for a guy his age, but needing some reassurance, he asks, 'How am I doing'?
The prostitute replies, 'Well old sailor, you're doing about 3 knots'.
Three knots he asks, 'What's that supposed to mean'?
She says, 'You're knot hard, you're knot in, and
you're knot getting your money back
