In 2010 or so, I started making a game called
Aquanautica Imperialis. It was the game of wet-navies in a Warhammer 40K setting. I made the rules based on BFG, Man-o-War, and a few other bits and bobs. I managed to make fleet lists for all major factions of the game, templates, scenarios, campaign rules, and even had a small following of people playing it online. I even made a follow-up game based on submarine warfare in teh 40K setting called
Aquanautica Imperialis: Battle for the Depths. It was one of my first forays into game design, and I still enjoy playing from time to time.
Anyway, to play the game I had to sculpt, convert, or scratchbuild my own fleets. I did this with the Imperial PDF, Ork Kill Fleet, and the Tyranid Sea-Swarm. Below you can see my North Ammoriss Naval Planetary Defense Force or AN PDF:
I sculpted these from Sculpey and painted them up. From back left across we have: A Reliable Cruiser, Steadfast Light Cruiser, and Dependable Cruiser. The front is a pair of escorts from left to right the Assured and Constant class. These are a half decade or more old.
If you want to give the rules a try, you can find everything you need online. Go to the blog in my sig, and look in the free wargames section.