Hello, I'm playing the new Chaos DLC and I am trying some pure lances fleet. I use acherons and hellbringers mk2. I've noticed that acherons never manage to crit the enemy engines, whereas the hellbringers do. I suppose it's because I use the hellbringers in stealth mode and manage to get them behind the enemies and shoot directly in the engines. Is that the case? What are other favourable directions to crit other system? Example: from where should I shoot to crit the deck or the generator?
That is precisely the case, and it's pretty straightforward. Whatever is visible, can be critted.
However you can crit generator from the front as it is considered to be on top, but it's relatively rare, sides and back are obviously preferable for that.
The same case with deck, except it's easier to crit from the front. Engine is the opposite, it pretty much can't be critted from the front (I may have seen it once or twice, but I can't vouch for that) but can be critted from the sides and if you're at the back it's the most favorable target.
Other than that, it's pretty straightforward really. Whichever weapons are visible from the sides you can attack, can be critted. So if you're on one side of enemy ship, you can't crit batteries on the other side.
Overall if you want to crit the engines, shooting at the back will increase your chances significantly as ships have no weapons at the back, meaning less potential crit targets other than engine/generator.
In other cases, it's a matter of RNG and setting up crit priority on the target (probably).
Excellent response from Ahriman, direction matters for what systems could be damaged if a crit is rolled.
Also keeping in mind the Class crit reduction for each ship (a battleship will only take 20% of crits where as a cruiser will take 60% of crits).
You can almost never crit the engine from the front, and these directional crits mean that you NEVER want your rear taking a pulsar volley as it will crit your engine most of the time.
Likewise with Imperial Broadsides, only the side getting fired on can be critted.
It's a neat system