I want to know the answer to the following question:
With out the letters of marque what wepon did  they have to protect themself that was a part of their ship?
All the background I'm provided with is that "This was not so that they could carry cannon to fend off warships, privateers and pirates on their voyages to India and China (that they could do without permission) but so that, should they have the opportunity to take a prize, they could do so without being guilty of piracy.". Is that enough to answer the question?
Answer: yes