Note that many pirate ships had Ship's Articles. Basically an employment contract with rules for the crew and officers. There are surviving articles, and to quote the rerun annotation "I know often crew members would sign up to the ship's articles with just an X. (At least, I know I've read that somewhere.)"Generally you'd expect the officers to be fairly literate. Several of the officer jobs have literacy as practical requirement (navigation, quartermaster, log keeping, etc.), so while the organization of a pirate crew is less regular than something like Royal Navy where officers are all upperclassmen and thus literate, a pirate crew is much more a meritocracy. The officers receive their commissions from the crew who would not suffer an incompetent in an officer role. Most pirate officers would have learned their trade as officers or officers' mates on naval or merchant vessels and would thus come from backgrounds where they have learned to read and write and would continue in such roles since they would be the most competent to fill such roles.
But writen articles that every member of the crew is expected to sign on for only really makes sense if there are multiple literate crewmembers.
Wikipedia claims that "the golden age of piracy" was the 1650s to the 1730s, the Gutenburg Bible was printed in 1455 and IIRC one of the first books printed was a reader to help teach reading. The first commercial newspaper was being printed by 1605 (regularly printed government newsletters pre-date this). So, while literacy levels were lower than modern, there were still a lot of literate people in period.
Statistics: Posted by Doug Lampert — 21 May 2025 18:09