Too Much Johnson.

Augustus Billings has a domineering mother-in-law, and to get away from both her and his wife, he takes a trip, claiming that he is going off to check on Mexican oil investments. But he's really going on a cruise with Mrs. Dathis, who has purchased his yacht. To throw everyone off track, he uses the name Mr. Johnson. When he decides to repeat the trip, however, all hell breaks loose -- the jealous Mr. Dathis is out to get his hands on this Johnson character, while a real Mr. Johnson shows up in Mexico, and Mrs. Billings shows up with her mother, and the confusion continues from there.