>>An argument could be made that it does not include heavy crew-served weapons, but at the time you had civilian ownership of cannons.
Not to mention well-armed ships with multiples of them.
Otherwise, there would have been no need for Letters of Marque and Reprisal to be in the Constitution.
No… the letters merely gave you authorization to attack hostile nations shipping on Americas behalf. They were not necessary for you to arm your ship for mere self defense against pirates.