Fun fact! The United States never signed the treaty that bans the use of Letters of Marque and Reprisal. Also, given the historical evidence in the War of 1812, where private citizens were not just permitted but encouraged to outfit and crew private warships against the British, we can determine that the Founders intended the Second Amendment to extend to cannons and other large armaments.

So, legally speaking, all that's standing between you and a life of plundering Chinese cargo vessels is approval from your congressman.