HMS Seal

The oddity, explained

Why is HMS Seal unusual?

HMS Seal appears here because the approved source classifies it as infrastructure. The source describes it as 1938 Grampus-class submarine. Heritage Atlas treats that specific classification-and-description combination as the oddity; the score is a comparative discovery signal, not proof of mystery or the supernatural.

Evidence and further exploration

The coordinate, category and description remain tied to the cited source. Comparative oddness helps discovery; it does not add facts that the source does not provide.