A Rogue Trader Cruiser is any class of Imperial Cruiser that is in the employ of a Rogue Trader dynasty. It can be a starship drawn from a variety of standard Cruiser classes. Imperial Cruisers are gigantic constructions, most of them Terran centuries or even millennia old. Those few that are constructed anew are often the result of standard years of toil by the population of an entire world -- enormous orbital shipyards that might produce a single vessel every few solar decades. Even the mighty Forge Worlds with their unimaginably vast, serried ranks of orbital docks and laying yards may only complete one of these behemoths every year or so despite easily having a dozen or more of them in varying stages of construction at any one time.
Such gargantuan efforts are beyond the ken of even Rogue Traders. Rather, most Rogue Traders rely on vessels built (and often owned) by others. Many Cruisers are in fact part of the dynasty's Warrant of Trade itself, an undeniably powerful aid gifted to the Rogue Trader by the Administratum as a bequest to their agent abroad. Other vessels are loaned to Rogue Traders more temporarily, perhaps being themselves Imperial Navy vessels given over to a Rogue Trader for a time where Imperial Command thinks it beneficial.
Rogue Trader Cruisers take an infinite variety of forms, all based on standard Imperial Cruiser patterns. The form these vessels take may vary greatly, based primarily on what particular Forge World either constructed the vessel itself or leased its Adeptus Mechanicus-approved design template to the orbital shipyard that constructed it. Thus, while Rogue Trader Cruisers are generally recommissioned hulls of many different patterns, the most typical Cruiser pattern utilized by Rogue Traders are those constructed at Kar Durniash, the Segmentum Fortress of the Ultima Segmentum, and its surrounding star systems. Conversely, for this same reason the pattern is also common to various Imperial Navy Cruiser classes that operate throughout the Ultima Segmentum, such as the Lunar-class, Tyrant-class, Dominator-class, etc.
Rogue Trader vessels are unique, exotic things, often exhibiting many signs of their colorful adventures. Although typically based around the hulls of the more common Imperial Cruiser classes, Rogue Trader vessels are subject to constant refit and adornment, much of it alien in origin, creating truly unique vessels. The business of a Rogue Trader can take him all over the galaxy and, while his vessel's class or hull pattern may be common in its sector of origin, it may virtually unknown in those which he travels, meaning a relatively standard Cruiser may stand well apart in appearance from its Imperial Navy counterparts. Drawing such flamboyant attention to one's self is something most Rogue Traders hardly seek to avoid.
Kar Durniash - Trader's Haven
Being the Segmentum Fortress of the Ultima Segmentum, Kar Durniash is a favoured departure point for countless voyages to the Eastern Fringe, the largest of the vast, unexplored tracts of Wilderness Space in the galaxy with its promise of adventure and undiscovered riches. Accordingly, it is also the return destination of many traders once their business in the Fringe is complete, and over the millennia has established itself as a welcome haven for exhausted traders and crews who may well have been beyond Imperial-controlled space for many Terran years. It is for this reason that Kar Duniash is the primary place from which Rogue Trader Cruisers are often created, leased or otherwise acquired.
- Battlefleet Gothic Compendium 2010, pg. 83