Just to be fair, the bismark's guns couldn't depress far enough to hit the swordfish, the problem wasn't with tracking the targets.
Yes, the problem was with tracking the targets. The speed of the Swordfish were too slow for the German fire-control predictors used by German gunners. This caused the shells to explode way in front of the planes, minimizing the threat of damage or being shot down from shrapnel. It also helped that some of the Swordfish came in so low that the Bismark's flak guns couldn't depress enough to engage the attacking planes.
Read "Pursuit: The Sinking of the Bismarck", it's a very good book about the pursuit and sinking of the Bismark.
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