this blog (christine demerchant) and its many lists of terms and informative pages, for example: sails & rigs & sailing, hull & construction terms, anchors & anchorage, types of boats & ships, points of sail - at the bottom of every page there is a list of books on the topic as well!! this blog is INVALUABLE and has basically everything, and if it doesn't have something it certainly has a link to another blog or a book that has what you need. there's also lot of interesting articles about the author's adventures in making her own sails and building boats and experimenting with sailing. the site is a little difficult to navigate but the information on it is incredible and all very experience-based!!

there's also this blog (roland's model ship building) which is SUCH a delight - it is mostly model ships as the name would suggest but it is an incredibly close look at the little complicated parts of ships and a great resource for the more "how does this look" aspect if a little less "how does this work". my favorite page is the process of building model HMS surprise - it's SO fascinating and even just a quick look through makes visualizing and understanding the physics of it all easier. this in particular is a very good drawing resource for tall ships!

the ever-famous shipindex.org is a completely invaluable resource as well. pretty much anything you want to know about a specific ship can be found here, or at least it makes a spectacular jumping-off point!

another famous resource is falconer's marine dictionary, or: "A New Universal Dictionary of the Marine; Being a Copious Explanation of the Technical Terms and Phrases Usually Employed in the Construction, Equipment, Machinery, Movements, and Military, as Well as Naval, Operations of Ships: with Such Parts of Astronomy, and Navigation, as Will be Found Useful to Practical Navigators" by william falconer and expanded by william burney - the whole text is here online but it can be a little hard to read and understand so i would supplement with the other resources here!

there is also the oxford companion to ships and the sea which i do not have a copy of nor do i have online access to the full text, BUT you can search and find keywords and it will show you excerpts which is surprisingly helpful!! especially good if you don't have time to read the whole dictionary trying to find one specific term.

in the same vein is the oxford encyclopedia of maritime history - same deal as the above and i do not have access to the full text but this is SO useful for looking up specific people and places and ships and battles and such!!! there's TONS of information in this one.

also, a super interesting primary source: digital collections of midshipmen's letters and journals in the united states naval academy!! these are hefty, each link contains a ton of stuff:

Richard Mueller Nixon Letters (1926-1930)

Henry Mylin Keiffer Scrapbook (1907-1911) (one of my favorites of all time, absolutely worth at least a cursory glance)

John Porter Merrell Johnston Letters (1932-1937)

William Frederick Durand U.S.S. Mayflower journal of practice cruise (1879)

Roscoe C. Bulmer Journal (1894-1896)

Josiah G. Beckwith Letters (1853-1855)