I'm trying to make an effective tank class in Deathwatch. Partly because I feel like I'm not supposed to. However, I am encountering a lot of problems, and I was hoping we could pool our ideas to improve the concept.
Let me list what I have started with, and then some problems I have encountered. Please add additional build ideas, and any solutions you can think of. I fear it will be futile to ask that the thread be kept to RAW, since houserules have little value in my group.
THE GOOD
I chose the Techmarine for cheap toughness and multiple armor upgrades. I chose Ultramarines for the bonus to toughness and agility. Since you are not likely to roll a starting stat of 50, your best stat will be in the 45-49 range, which means the toughness bonus will give you two extra toughness initially and ultimately.
There seems to be no end to the defensive upgrades available, including somewhat hidden abilities, like Trade (armourer) and Evaluate. Early on (Rank 4) you can get some Artificer armor, which offers 13 AC to each location (as it is always master crafted). Opting to purchase a cybernetic in each location increases your toughness by 2 regardless of hit location. Masking Screen decreases enemy accuracy, and storm shield deflects shots while also increasing AC. (Depending on the reading of the rules, this may be interpreted as an illegal combination)
By the time you get your Machinator Array, your TB will be 18 in each location. Your AC will eventually be 13 base, +5 for The Flesh is Weak, +4 to multiple locations from your shield, +1 for master crafted Masking Screen, +2 for blessing your armor. Total average AC: 23
A shot of 41 will do no damage. With high dodge and defensive stance, you will automatically dodge the first two attacks per round, then have a 45% chance of deflecting additional shots (storm shield).
THE BAD
Defensive stance always takes a full action, which means you can't move in the least, and everyone else will have to move to get behind you.
Ultramarines offer no distinctly defensive upgrade options or powers. Some chapters have excellent defensive options, but you will give up your extra toughness, suffering two extra damage per hit.
Chapter trappings and Storm Shield improve Parry, which is practically worthless to this build.
Guarded Attack becomes worthless to this build (Dodge is already at 95+ percent), and thus the bonus gained from your Storm Shield. (If only Storm Shields let you use Defensive Stance as a half action, and you could move a little).
I tested with my Rank 1 character, and survived 10 out of 10 test Lascannon shots, without critical damage. But I want to tweak the build more.