Just thought I'd throw this out there and see if there were any thoughts. I have been doing some research on the Queen Annes Revenge and decided to look at similar ships in the time period. I have a book called "Story of Sail" by Veres Laszlo and Richard Woodman. It has over a thousand plans and information about ships through out history. As I looked at frigates within the time period a particular ship got my attention. The Sweepstakes was a frigate built by the British in 1708. It had 22 guns on the upper deck and 14 bigger guns on the lower gun deck. According to the book the ship was fast but the lower guns were to few to be effective and the ship was captured by the French. Sound familiar says I.
So I thought if QAR were a very similar ship to the sweepstakes what would have happened after her capture by the French. Likely they would have sailed her home and some one would say, "thats a fast ship to bad it's a frigate lets re plank her into something more useful." So they would re plank the ship covering up the gun deck leaving only the vents and make her a merchant ship and slaver. Later it would be captured by Benjamin Hornigold and given to Edward Teach. Teach seeing the gun deck would think, "this would make a great pirate ship given it had use of this gun deck." Twenty or so portholes would be cut out, which would no longer be to few to be effective, and the QAR would become a fast 40 gun frigate.
Just a shot in the dark and chances are we'll never know but thought I'd see if there were any thoughts.