It was briefly mentioned in one post regarding Slocum's book (http://sailfar.net/forum/index.php?topic=2097.0); but there are lots of FREE audiobooks available at https://librivox.org/. All the books are in the public domain, and the narrators are volunteers. A good choice for audio entertainment.
I once thought about volunteering to read books for this site. I have yet to get around to it though.
I did meet a man in New Bern who had a small recording setup on his ketch. He had a few small gigs recording audiobooks that kept some money coming in.
Might be a good sailing gig if you like the sound of your own voice! Then again, his partner did roll her eyes when I asked if she ever got tired of "reading along" ;D