These 2 upgrades buff one and the same thing. Maybe you could change it so CSM give a morale and crew buff.
We all know what happens with stackable upgrades. Please consider looking at this.
I though the hell drake forge buffs assault boats and CSM the ship-boarding actions.
Did you mean Khorne Berserkers? They do seem to buff the exact same thing as chaos space marines.
@jamodon yeah! Zerkers with drakes sounds like cancer.
I tested it in-game. hell drake forge does not change the ship boarding crit chance. you can stack zerks with CSM to reach dark eldar crit chance with boarding, but zerks don't increase the lightning strike crit chance.