Dogger Bank panic versus the Novorossiysk frogman theory

Which is less plausible: Japanese torpedo boats attacking the Russian fleet near Britain or Italian frogmen sinking Novorossiysk?

The claim about Japanese torpedo boats is less plausible because of the distance from any base, although both explanations are judged unlikely.

Japanese torpedo boats are the less credible of the two explanations. Small craft would need a workable base and route to reach waters near Britain during the Russo-Japanese War. The Italian frogman theory for the loss of Novorossiysk is also judged unlikely. Logistical feasibility weighs most heavily against the Japanese story, and neither account is accepted as fact.