Not sure why you think the sea state would eliminate the advantage of long range shooting. From some of what I've read over on kbismack the German radar was actually pretty good. There was also some pretty good shooting at long range in the North Atlantic. The problem for the Germans is that the US practiced long range engagements and their doctrine was to keep the engagement at long range. The redundant radars would also be a factor as even shorter range engagements might require or at least significantly benefit from radar fire control due to visibility issues. As for taking damage the German ship might be able to take more and stay afloat the question though is how much could it take and keep fighting in comparison with an Iowa. Looking at Nathan Okun's tables Bismarck's turret faces can be penetrated out to over 28,000 yards by Iowa's guns. The upper facet looks to be penetrable at any range and the turret roofs at anything over 26,000 yards. The barbets are vulnerable out to around 30,000 yards as well at over that hits are unlikely in any case. In comparison the Bismarck has to get under 18,000 yards to penetrate Iowa's faceplates and only starts penetrating the turret roofs at ranges in excess of 38,000 yards. Nathan Okun has a fairly detailed comparison of Bismarck's armor scheme to that of several contemporary battleships (SoDak is used rather than Iowa for the US). It doesn't inspire confidence in the ability of Bismarck to soak up more damage than Iowa.