In the "Bridge Hug Scene" right after the "Croc Nest", Dagwood is not carrying the corn dog.
When the crocodile is buried with ice blocks resulting from the torpedo blasting, the ice should float instead of going to the bottom. Cold water is denser than ice, that is why icebergs float.
Before Jenna jumps off the boat with the camera we can clearly see it is a SeaRay with twin inboard/outboard drive units, after gets in the water and the shot shifts the boat has rudders, which would not be the case if it had I/O drive units. The boat is also much darker.
When Rick and Jenna return to their boat with the underwater samples it seems they are attacked the boat is spun around. In the long shot we can see the prop wash from the engines making it obvious that the boat is simply in reverse and running under it's own power. Further we see a shot of the back of the boat and disturbed water around drive units indicate the engines are running. In the next shot they are not.