A bottle in the dispensary is labeled "Hawley and Pratt Salts." Hawley Pratt was the layout artist for this cartoon.
Ocean travel was still the norm for most folks at the time, though the airplane was becoming more common. The details of the ship, and the piers it's tied up to (barnacles, sea stars, mussels) are careful rendered, as they were during animation's golden age.
All of the characters break the fourth wall in various ways.
One of the few times Tweety is heard singing, even if he is off screen.