Sometimes the mast of PT 73 is shown behind the bridge and sometimes it isn't.
Ens. Parker's collar bars are missing when he impersonates the Capt. He also should have had gold eagles as required for the rank of Captain.
When Virgil is welding, the flame and rod never get close to each other. When Binghamton reacts to getting burned with the flame, the flame never comes close to him.
When Binghamton is on the pier and 73 starts pulling away before casting off the line, you can see the line where the pier will break apart. Plus Binghamton is standing in the center but when camera angle changes, he is on the very side of pier before falling into water.