So, everyone has to say thanks to my brother, who spent more time studying physics than I did (I'm more a biology man). Using ideas from the post-Maxwellian pre-Einsteinian era - don't ask me when that was, I don't think I even got the names right - he's made a working set of physics for the Oddverse. Back in those times, they thought the universe was filled with a gas called (surprise) ether. Basically, it allows for faster-than-light travel, because of something important I forgot whilst doing my own calculations.
In space, it is not about the speed limit. It is about the acceleration. I may have to correct this if I make a mistake, but according to my brother an acceleration of 3G (three earth gravities) would mean a ship would take 10 days to travel 10 lightyears. An acceleration of 1G would make the same journey last 17 days.
If the ship's maximum acceleration was 3G, then it'd be more sensible to take the extra week travelling than not leave any room to accelerate in case of attack or emergency. The ship has to figure out the distance they need to travel, and spend half the trip accelerating and the other half deccelerating. That's the best way to do things, though currently the Black Hole has no real destination and it just ramming through the ether at 5G.
Which brings me to this: accelerating at 5G would, in theory, mean that you'd have to put up with five times normal gravity for the entire trip. Luckily, the Oddverse has the gravity planer, or just planer, which effectively cancels out the gravity on board a ship and affects whatever normal gravity the owner's set it to. This is a good thing, as the Black Hole's engines are at the aft, and we'd all be squished together
(For reference, 1G is equal to 9.8 meters per second per second. So for every second the Black Hole travels, its speed increases by 49 meters per second. It'd take about 1,700 hours for it to get to lightspeed (299,792,458 meters per second) at this rate, but if Nemma pushed the engines flat-out as fast as they can go, the acceleration would be about 12.5G - however, that's fairly dangerous.)
Anyway, speeds: Dragons can push themselves to 1.8G at most, but prefer speeds around 1G. Sorcerers are usually travelling about 5G leisurely, but can push themselves to do three times that if they have no regard for personal safety or pain. They have no planers, so they feel ever single G unless they cancel them out - trickier the faster they go. Yuri, being pretty powerful, can do this better than most others, so his top speed's around 25G before he kills himself.
Most ships do about 1-5G, but save the 3-5G range for maneuvering and escapes. The more expensive ships, Capitalist and Nobility, can go to about 15G maximum (the Black Hole's fast, but not exemplary) but after that you need specially reinforced planers to cope - something that's too expensive for either Capitalists or Nobility to put in any ship but those that deserve it.
Carrion hulks, the Undead carrier ships, only do about .7 maximum. Their size and age, not to mention their low numbers, mean that they rarely risk being destroyed or captured. They mostly stay within the Undead systems, only emerging when they desperately need fresh blood.
I think that's about it. Hope you bothered to read this!