Royal Order of Whale Bangers
Throughout WWI and WWII, allied pilots had a hard time distinguishing whales from U-boats. Numerous newspaper articles were published relating to this topic over the years.
The Creation of the Royal Order
This happened enough during WWII that American bomber crews flying over the Atlantic created an award to that effect: Any crew belonging to VP-53 squadron that sank a whale instead of a U-boat was awarded the (non-official) certificate of the Royal Order of the Whale Bangers by their peers!
Modern Context and Incidents
The issue can still arise in a more modern context: British warship HMS Brilliant targeted a pod of three whales during the Falklands War after mistaking them for enemy submarines!
-RBM.