For the price of the cruise, booze, and entertainment I will — specify the mounts and siting of your M2HB guns, specify the ammo you need, specify your crew's protective equipment (helmets, flak jackets), and train your gun crews in the care and feeding of Ma Duce. All you have to do Mr. Cruise Line is have a desire to protect your investment, be willing to do some paperwork, and have a check book. I can fix your piracy worries.
BTW, you could make money by renting the guns out to the passengers for recreational machine gun shoots. Most cruise lines would be surprised on how many cruise guests know how (or want) to shoot Ma Duce.