Rok theory, So I've been holding back on any thoughts for the Roks, but I've been thinking about them lately as I've been building the 'Flawed Ships' Pdf.
Here is a size chart from wikipedia:
It shows the number of asteroids that have at least the mean diameter listed in our solar system.
100m | 300m | 500m | 1km | 3km | 5km | 10km | 30km | 50km | 100km | 200km | 300km | 500km | 900km |
25,000,000 | 4,000,000 | 2,000,000 | 750,000 | 200,000 | 90,000 | 10,000 | 1100 | 600 | 200 | 30 | 5 | 3 | 1 |
Presumably orks would use Asteroids at least 5km in diameter to build Roks. Which is plenty of space for anything and they are readily available.
So from Warp Rift these 'upgrades' could be garnered:
Weird boy towers (basically short ranged lances)
Launch Bays
Fire ship rules
Soopa engines
Now Soopa engines and Launch bays are easy. Launch bays would be Str 2 and replace heavy guns for +20? points. Soopa engines would reduce the strength of the guns to D6+2 but allow it full AAF rules.
Fire ship rules are pretty easy too, it would sacrifice all weaponry (maybe keep heavy guns) for the fire critical option.
The weirdboy towers I never really liked, as the idea of psykers manipulating huge ships in any significant way just seemed out of reach.
Anyways lets look at the points value of roks, smotherman doesn't go into how defences are calculated, but we can do some math to figure out how valuable the hull of a Rok Is.
For a capital ship with 5+ armor the average amount of FP needed to statisically do 1 hit is 7.41. For a rok this is 3.75 (a shit-ton less) Not only that nearly 1/6 hits will cause a critical and do an extra hit. However these could do more damage to the Cap ship, So 19/36 results on a standard critical will do at least 1 point of damage. Roks will take points from H&R, but this is a trade off as Cap ships could take multiple on some of the results. (this counts fire as one).
Ultimately this means that about 50% of criticals will cause extra damage on a capital ship, so to balance only 1/12 of the shots will do more damage than normal. Effectively this means that the FP will be reduced to 3.55, divided by 7.41. So about 50% the survivability of an equivalent cruiser.
Meaning that a Rok looks like a 4 hit capital rather than an 8 hit one. Reasonable, as the cost is 80 points.
So Ultimately, the Roks are more like escorts than anything else.
Upgrades (Proposed):
May reduce strength of the Guns Battery to D6+2 and add soopa engines at no cost.
May Replace the ships heavy guns with 2 launch bays for +20 points.