Along that line, when uncertain as to whether classify a sonar contact as a whale or an enemy submarine, the correct decision is to classify with ordinance.
This means that you drop a torpedo on it. If the torpedo explodes, it WAS a submarine.
WWG1WGA
Garde la Foi, mes amis! Nous nous sommes les sauveurs de la République! Maintenant et Toujours!
(Keep the Faith, my friends! We are the saviors of the Republic! Now and Forever!)
LonePalm, le Républicain du verre cassé (The Broken Glass Republican)