pg 2/14:
The Imperial Navy
…All human-inhabited space is further broken down into sectors, which are most usually cubes of space roughly 200 light years to a side. Each sector is comprised of a number of sub-sectors ranging from ten to twenty light years in diameter, centered on densely populated star clusters, important worlds, or meeting pots of various trade routes through the warp. The areas between sub-sectors and sectors – unexplored or uninhabited regions, alien empires, areas inaccessible by the warp ect, --are known as wilderness space or wilderness zones and make up a far greater proportion of the galaxy than that controlled by Humanity.
For all practical purposes, a sector’s battlefleet is the largest operational naval orginisation, under the command of a Lord Admiral. Each battlefleet is then divided into a number of battlegroups. Battlegroups are not permanent organizations, but instead task forces, convoy escorts, patrol flotillas, and other fleets that have been assembled to perform particular functions…
My, my, what do we have here? The Imperial Starfleet is more or less, divided into 75 warships (max on average) per 200 lightyears (sectors). Even giving them say, 100,000 LY to work with, that's only 37,500 starships for the Imperial Navy. More reasonable estimations of about 50,000, we'd get about LY 18,750. In addition, they would also have numerous defense ships that are pretty much limited to STL speeds.Warships of the Imperium
Each battlefleet normally consists of between 50 and 75 warships of varying size, although in some sectors there will be more or less, according to the importance of the sector and the number of enemies it must contend with. As well as these destroyers, frigates, cruisers, and battleships, a battlefleet also has access to countless smaller vessels such as transports, shuttles, messenger craft, and long-range patrol craft. In addition to interstellar vessels, as sector will also be protected by numerous ships incapable of warp travel, such as system patrol ships and defense monitors. These are stationary defenses – space stations, orbital defense lasers, and missile silos and orbital mines.