Nikolai Lunin did not directly observe the result of K-21's torpedo attack on the Tirpitz, but noted sounds of explosions which he interpreted as torpedo hits.
Notes on verification
Multiple independent Russian-language sources (Wikipedia articles on both the attack and submarine K-21, plus historian-cited popular history site) and an English-language mirror consistently confirm that Lunin did not visually confirm the torpedo hits and relied on explosion sounds. [tier=unverified indep_score=0.3 clusters=2 claim_tier=notable] [rescored 2026-09-15: curated origin-host map (PR #65); unclassified hosts no longer scored as aggregators]