There are no actual instructions here, but The Penny Whistle has some really neat photos of index card ship models. They should be relatively easy to replicate and look like they could be used in a fun game.
Naval
Building A Pre Dreadnought Battleship From Scratch
Here’s a very involved tutorial on making a pre dreadnought battleship from scratch.
Instructions For A Naval Landing Party
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.
Photographic History of the US Navy
NavSource is an interesting site with photos and stats on hundreds of US navy ships. I spent way too much time browsing here.
Commodore Fighting Sail Card Game
WarpSpawn offers Commodore, a two player card game of Napoleonic fighting sail.