Men O’ War is a set of free wargames rules for Napoleonic sail. The rules are aimed at small actions, with one or two ships per player.
Battle War At Sea is a set of free wargames rules for modern naval warfare. It is designed for 1/6000 scale ships
Jutland: The Rules of the Game are a set of free wargames rules for large scale WWI Fleet Actions.
The Immortal Memory is a set of rule for refighting Trafalgar.
Dark Days of the Admiralty are a set of rules for Victorian Warfare:
These rules represent mid Victorian naval warfare, in many ways as naval officers of the time assumed it might be.
They are intended for fleet actions between the major powers. In fact there were no such actions in this period, from Lissa (1866) to Tsushima (1905). There were however many actions involving smaller powers – for example the wars in South America, the American Civil war and some small actions involving the great powers in for example the Franco-Prussian war.