Nikolai Lunin did not directly observe the result of K-21's torpedo attack on the Tirpitz but interpreted heard explosion sounds as torpedo hits.
Notes on verification
Confirmed by Wikipedia and multiple independent naval-history sources drawing on Lunin's original report and archival accounts; consistent across sources that the attack result was inferred from sound rather than direct observation.
Sources
- Attack on the battleship Tirpitz by submarine K-21 (en.wikipedia.org)
- https://forum.axishistory.com/viewtopic.php?t=126564 (forum.axishistory.com)
- https://weaponsandwarfare.com/2015/03/02/k-21-versus-bb-tirpitz/ (weaponsandwarfare.com)