When Hot Lips and Scat disguise themselves as the barber and shoeshine boy, Hot Lips begins to put shaving cream on the guy in the chair, including his mustache, but the close-up shows no shaving cream on his mustache.
While Hot Lips Barton (Bob Hope) is preparing for, and performing, his high-wire bicycle act, the ball on the right end of his balancing-bar disappears and reappears several times.
The first time we see the aunt hypnotize Lucia, the shadow of her hand on Lucia is different between the wide shots and the close-ups.
When Hot Lips and Scat try to make a passenger seasick, the passenger puts his fork down twice.
Right after Harry and Tony knock each other out, Scat Sweeny takes his earring off twice.
According to the thermometer next to the door, the temperature inside the ship's meat locker drops to below freezing, but Hot Lips and Scat never have white breath.
Throughout the film Frank Faylen's character is called "Harry" but on the closing credits he's listed as portraying "Trigger".