Thanks for putting this in a thread. The 1k character limit on the comments is really hard to explain anything in :)

So the turn rates listed in the game are slightly misleading. They are correct values, but they don't tell the whole story. There are approximately three turn rate bands I've calibrated those values around in terms of time to turn 180 degrees. 0-3s, 3-5s, 5-7s. Using those goal times I've got a formula that I list the max time to turn for each ship class which tells me the correct turn rate value to use.

It's been a while since I worked with this section, but as I recall, the turn rate is how fast the ship will build up momentum to the MAX TURN value. This Max Turn value is what you see in game. So for example, a titan has a max turn of .3 with a turn rate of 0.05 while a dreadnought has a max turn of .25 and a turn rate of 0.38. The result is that a dreadnought will take 6.5s to make the 180 while a titan will take 6s to do so.

The times for all the hulls are currently:
Bomb Ketch: 2.5s
Frigate: 1.25s
Destroyer: 2s
Ironclad: 3s
Cruiser: 3s
Gunship: 2.2s
Battleship: 4.5s
Battlecruiser: 4.4s
Titan: 6s
Dreadnought: 6.5s

Doomstars aren't touched from 5x yet.

The result is that a frigate can outmaneuver a destroyer, destroyers can outmaneuver crusiers, cruisers outmaneuver battleships, and battleships outmaneuver titans.To be honest, the added classes from 5x make it really hard to have much greater variance. Start too fast and turning means nothing, while expanding to a much slower value would result in titans barely being able to turn. Threre's a balance between painful and just slow :)