Revealing mistake: When the shark is on the deck of the Andrea Gail, you can see the equipment underneath it that is making it move. (00:47:30)
Revealing mistake: When Capt. Billy Tyne climbs up the boom to free the loose anchor, instead of a real flame on his cutting torch, there is what appears to be a piece of illuminated glass.
Revealing mistake: Towards the end when the boat is going up the huge wave, notice Billy and Bobby are keeping their balance although the boat is straight up and down.
Answer: That's not how the refueling line works; it would only dispense fuel if the helicopter's line was attached. Even if it didn't, the fuel they released would have been immediately swept away by the gale, diluted with the rainwater, so any minute amount that miraculously entered the helicopter's line would have been completely negligible and wouldn't have made a difference.