Hi KAB.
I've Bareboated 47 foot Catamarans from the Moorings in BVI twice.
As I
recall, they wanted a Boating/sailing resume, and letters of recommendation. Based on a resume they seem to set limitations on the
boats they are willing to let you bareboat. I can't speak to other companies. Though, I did charter a
monohull on Lake Tahoe once and all they wanted was a passing grade on their 10 minute written test.
In the BVI, I am fortunate that two of us held our US Coast Guard Masters licenses and are Certified as Instructors through
ASA. (monohulls). Prior to that I had spent little time on Cats. We found no problems sailing a cat in the BVI. It's paradise!
I do not believe they would have given us the keys to their 1/2 million dollar vessel, on a credit card and a smile.
If you've crewed and chartered before, you could have had the charter company certify your time and kept you in their files. The moorings maintains a file on your charters, and gives a returning captains discount.
Taking the ASA catamaran course or another recognized course, getting certified, a letter from your instructor or the schools owner and a resume of all your previous time should do the trick.
Good luck and good sailing
Tempest..