When Sandy first arrives at Porter's house, he switches between wearing sneakers and sandals at least four times.
Sandy gains shoes when knocked off the wharf into the water.
When Sandy is awaken by Flipper on the dock, by Flipper splashing him, his hair goes from barely wet to soaked.
When Sandy is swimming underwater with Flipper after being knocked off the dock while working, his watch and armbands flip hands during one scene with his watch on the right wrist and armbands on the left.
While on board the Reliable searching for toxic waste (potentially for three days), each person's clothing changes at least three times, but Sandy's shirt changes seven times among four different shirts: a Smashing Pumpkins shirt, a DINK shirt, a stag head shirt, and a solid gray shirt.
Sharks are unable to make sounds.
When the boat is bearing down on the boy near the signal marker, the tracking radar shows it ahead of the boat but off to the right, at about the one o'clock position. As they close in on it, the distance on the radar gets shorter but it stays at the one-o'clock position. If they were heading straight toward it, it would be at the twelve o'clock position.
SpaghettiO's are not considered food for breakfast, so Porter shouldn't have to cook them.
When Sandy first sees Flipper in the water and follows him along the dock, he walks on the same section of dock twice.
When on board the Reliable and searching for the hazardous waste drums, Cathy says "go downstairs". A real ex-Navy type would have said "go below".