Robert Comsol wrote:
An analogy to a Klingon Battlecruiser might be the Roman Trireme
(Roman galley) where most of the operators required for "propulsion" were slaves. Admittedly, that's a crew complement you'd rather expect to see with the Rom(ul)ans, but maybe an explanation how they got their name during the Earth-Romulan War...from a strictly TOS point of view, of course.
Although this is not really the topic of this thread, I nonetheless would like to correct this very common misconception: There is no proof whatsoever that Rome or other ancient powers utilized slaves as rowers on their galleys.
An article on galleys can be found here, pay attention to the last topic "rowers":
During a battle galleys solely relied on their rowers for speed and maneuverability and thus ultimately for their survival. So the rowers had to be healthy, well nourished, motivated and able to work as a team - that many oars had to be operated in unison and as needed. Ben-Hur perfectly illustrates what happens when (ill-treated) slaves are being used instead.