Overboard (1987)

Joanna hires country carpenter Dean to build a closet on her yacht. When the two don't see eye-to-eye, Dean is left unpaid while Joanna sets sail. The following day, Joanna is fished out of the sea, after falling overboard, suffering from amnesia. Dean sees a neat way to regain the money she owes him - he tells her she's his wife; that way Dean gets a free housekeeper and mother for his four kids.