I can't use the version closer to the original meme, because it would be bypassing profanity filter. Derelict Contingent skill offers 15% chance to reduce incoming damage to hull to 10%. This is pretty good, but you don't even know how. It also offers a few other scaling bonuses: -10% crew casualties per d-mod (actually useful, because hull tanking is what those ships are going to be doing), +3% max CR and, if the ship doesn't have any shields, it also gets +5% more residual armour. Last one helps, but first let's tackle the chance to reduce damage.
Let's begin with some math...
15% chance to reduce damage to hull to 10% results in average reduction to 0,865, results in approximately 16% more hull points.
30% chance to reduce damage to hull to 10% results in average reduction to 0,73, results in approximately 37% more hull points.
45% chance to reduce damage results in 0,595 average damage received, which is like having 68% more hull points.
60% chance to reduce damage results in 0,46 average damage received, which is like having 117% more hull points.
75% chance to reduce damage makes you take only 0,325 of the damage on average, which effectively gives you 208% more hull points.
Yeah, Derelict Contingent turns 5 d-mod, officered ships from junk into nearly impenetrable walls, but it doesn't end there! You also have minimum armour, which is increased by the skill for shieldless ships (mechanics of which I can't reverse engineer) and makes them tankier, than if they used shields. Though that point might not actually matter, thanks to Impact Mitigation, I'm not sure how IM and residual armour interact now.
CR over 70% offers another damage reduction, admittedly small, but at 5 d-mods it's +15%. You can get another 15% from Crew Training, but that depends on the size of your fleet. That makes the ship have effectively 224% to 242% more hull.
And then there are officer skills. Since Derelict Contingent requires officers to get all these effects, this is a non-issue for 8+ DC ships. What skills will come in useful here? Impact Mitigation increases armour value for damage reduction calculation by 150 points, which used to apply to residual armour as well and probably applies to it still, so any damage of hit strength below 150 (anything weaker than Assault Chaingun) has its damage reduced to a half or less. At this point, my 5 d-mod Enforcer with compromised armour and 10 200 HP managed to sustain approximately 80 000 damage from Assault Chaingun (eight times the stated hull durability!).
And then there's Damage Control, which simply reduces damage done to hull by 25%. Ignoring residual armour and assuming 85% CR, this allows your 5 d-mod ships to have more or less 322% more hull than it should. Which is to say, I wasn't paying attention and tested that officer using an officer that doesn't have Damage Control, so it could have tanked 104 000 damage from ACG before dying, if I remembered to get a proper skill mix.
WARNING: APPROXIMATION ABOUND FROM NOW ON
Using all the dirty tricks, I got following results from testing: I tested that Enforcer and came with the 104k hull number as approximately what it gets against ACG-strength weapons, or more than 10 times the stated hull points. Then I tested a Venture against ACG as well, and the result was approximately 483 718 effective hull points against ACG, or 28 more times than its stated HP of 17 000. Admittedly, I picked a Venture that has both armour and hull intact, so ymmv. But I thought that no one would use ACG to crack Ventures, so I decided to switch to Heavy Blaster testing, and it sadly wasn't as good. Against that, that Venture had only ~162 679 HP. Tripling the hit strength triples your damage output, makes sense in this situation. It's still nine and a half times the stated Venture HP.
Then I thought like being silly, so I grabbed militarised subsystems, assault package (which increases hull integrity by 10% and armour by 5%, and increases flux by 10%, but that's not important right now) and Auxiliary Support (if a single Venture is the only militarised ship in your fleet, then it receives +300% bonus from assault or escort package). That Venture had 2024 armour and 21 000 hull. I decided not to even bother with ACGs and use only Heavy Blasters in testing, and against them, the effective HP against HBs was 278 515, 13 times as much as stated!
Besides making ships incredibly tough, this skill has another downside: it means that for low-tech, pristine ships are the worst ships. 5 d-mod ship, even with compromised structure, armour and hull, is still going to be way more durable than a pristine ship.
How durable can be an Onslaught with 5 d-mods? Enough to survive two and a half minute of constant barrage of missiles and projectiles from Remnants. The only reason it can't kill them is because it can't keep up with them (and, of course, the famous flanking vulnerability of Onslaught)
