Could Vian's destroyers have overstated their claimed torpedo hits on Bismarck?
Short answerYes. Rough seas and darkness made overclaiming possible, but three claims from sixteen documented launches remain plausible enough to leave the question open.
NotesWartime forces often overstated claimed successes. Rough seas, darkness, and explosions in the water could mislead destroyer crews, so the reports are not proof. Three claimed hits from sixteen documented launches nevertheless seems plausible for a well-practiced formation. That is a judgment about probability, not a definitive reconstruction of damage to Bismarck.