An old retired sailor puts on his old uniform and heads for 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 three 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!"