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.