Dr. Lecter
Contributor
Stealing (copying or destroying) company data is illegal. Recording where you have been with your own GPS is not. I realize the numbers are the same in the end, but its how you get them that matters. If you sign a contract that prohibits your from using a GPS and do so anyway, then you can get you butt sued, but its not a criminal offense and the CG is not likely to do anything. If the captain ask you not to record and you do anyway, he can kick you off the boat just as he can for just about any reason he wants, but not much more, legally anyway.
This is the correct response. Assuming you've contracted to not record GPS information during the voyage, you could be sued for breach of contract if you do so (good luck to them in proving a concrete number for damages, though). And they could refuse to provide further services under the contract.
But some of the other stuff I've seen tossed around in this thread by persons who forget just what authority a captain does and does not have on their vessel amuses me. Tossing a piece of gear overboard is at least an intentional propery tort that will result in your paying for the replacement cost of the gear destroyed, if not punitives for the intentional nature of the tort. It may also be criminal destruction of property. Depending on how you take the gear from the objectionable diver, you may be commiting an assault and/or battery -- intentional tort with prospect of punitive damages, and criminal charges there, too. Suffice to say that any captain who secured a diver who breached their no-GPS contract in a 4'x4' jail on board the ship would (at the very least) wind up turning the dive boat over in order to pay the judgment against them -- unlawful imprisonment carries with it harsh civil and criminal penalties.
At the end of the day, you can run your salty mouth about protecting your numbers all you like. You can refuse to do anything more than return an offending diver to the dock and bar them from the boat without refund. But you cannot run around destroying property, physically engaging others, or locking them up because you suffered a breach of contract. Self-help is not available to you for that harm, no matter how much you think it should be.