When you read naval fiction set in the Ages of Sail you often want to know more about life at sea during the period. You can not put everything in a book and it is helpful to have sources to expand your knowledge. You can of course buy a non-fiction book or look up the glossary but if you would like to widen your knowledge in a more relaxed way you could try a Podcast.
The site republicandempire.com/white-ensign has a series of Podcasts which use the books of Patrick O'Brian as a route to discuss various aspects of naval life. Some recent examples include Puddings, Portsmouth, Privateers and Ships & Boats of the Mediterranean, which shows the variety of subjects covered.
EDIT: The site is currently down for technical reasons and may not become available again