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.
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.