Here’s a very involved tutorial on making a pre dreadnought battleship from scratch.
Vintage Wargaming has some scans of instructions for 1910 era naval landing parties. It’s a nice look at the world back then — and gave me some interesting ideas for games.
NavSource is an interesting site with photos and stats on hundreds of US navy ships. I spent way too much time browsing here.
WarpSpawn offers Commodore, a two player card game of Napoleonic fighting sail.
Malta Convoy is a WWII Simulation of the Allied relief convoy to the British island stronghold of Malta in August 1942.
It looks pretty good, and I think there’s the basis of an interesting campaign game here.