HistoryWorld War II (1942)Arctic Ocean / Norwaylow confidence

The German squadron did not detect the submarine K-21's torpedo attack on 5 July 1942.

Notes on verification

Confirmed by multiple independent sources, including detailed historical accounts referencing German documents and Soviet records, consistent in describing the undetected torpedo attack. [tier=unverified indep_score=0.3 clusters=3 claim_tier=notable] [rescored 2026-09-15: curated origin-host map (PR #65); unclassified hosts no longer scored as aggregators]

Sources