Why Some Submarines Return to Port Flying Pirate Flags

The Rebellious Reason British Submarines Fly The Jolly Roger After Missions

Jolly Roger, Did All Pirates Fly The Skull And Crossbones?

Did US Navy submarines have a way of showing how many enemy vessels they sank on patrol when they returned to Pearl Harbor? - Quora

Why did one of the U.S. Navy's most advanced subs return to port with a pirate flag?

Submariners: underhanded, unfair, and damned un-English? - Pacific Navy News : Pacific Navy News

This Navy Destroyer Flies a Pirate Flag: USS Kidd and Jolly Roger

This Navy Destroyer Flies a Pirate Flag: USS Kidd and Jolly Roger

Why Some Submarines Return to Port Flying Pirate Flags

Where does the stereotypical skull and crossbones flag actually originate? Pirates or Hollywood? : r/AskHistorians

Did submarines use flags underwater? - Quora