All at sea

A couple go off on a cruise. The wife is a bit of a harridan and the bloke is quiet and reserved. Towards the end of the first evening, she decides on an early night and he says he'll stay for a nightcap. "Don't be too long," she orders.
He joins a group of blokes at the bar who are playing a game where they each pick a subject and have to entertain the company on that subject for five minutes. When it comes to the quiet bloke he picks 'Sex' as a subject and regales them for five minutes with a succession of funny stories that has them rolling in the aisles.
Back in his cabin later, his wife is sitting up in bed, curlers in and covered in face cream. "You've taken your time!" she snaps. He tells her about the drinking game. "So what subject did you choose?" she asks.
He blurts out the first thing that comes into his head. "Yachting". His wife just snorts and switches out the light.

Next morning at breakfast, the wife is astonished by the number of male passengers who greet her husband, slapping him on the back as they make their way to their tables. Finally, she grabs one by the arm and asks him what's going on. "Your old man's quite the raconteur," says the bloke. "He certainly knows his subject."
"I don't know how, " says the wife. "He's only ever done it twice. The first time he was sick and the second time his hat blew off."

Pete