An old retired sailor puts on his old uniform and goes down
to the docks once more for old times sake.

He hires a
prostitute and takes her up to the room.

He's going at it as best as he can for a guy his age and
asks, "How am I doing?"

The prostitute says, "Well, sailor, you're doing about three
knots."

"What's that?" he asks.

She says, "You're knot hard, you're knot in, and you're knot
getting your money back."