For those of you writing fantasy involving boats and sailing, here are some links I found while researching for a short story I never finished. I got distracted by some other story. (Yes, I get Shiny New Story Syndrome pretty bad sometimes.)
Not sure what that nautical term means or looking for a suitable word to describe something on a ship? Check out The Phrontistery. They have a word list of nautical terms.
Wikipedia also has a glossary of nautical terms.
Marine Waypoints has a glossary and more. Their database has blogs, articles, a directory, books, news, photos, and the current tides and weather.
Ever wondered about the history of the astrolabe? The Multimedia Catalogue has a page about them featuring the planispheric, the universal, and the Rojas universal astrolabes. If you click the glossary link up at the top, you can find other science related terms, not just nautical terms and equipment. The few I've read through are well written. Some of them even have pictures.
Hope you find these helpful at some point even if you don't need them right now. Enjoy!