The evidence problem with U-boat radio taunts

Did submarine commanders really taunt escort captains over the radio as shown in Greyhound?

No reliable firsthand account has surfaced, and the behavior would have been operationally unwise despite the many stories repeating that it happened.

Routine radio taunts from U-boat commanders are doubtful because broadcasting was unnecessary and potentially hazardous. Stories that someone heard of such an event are weaker evidence than an account written by a person who was actually on the bridge or in the radio room. The conclusion remains open if such a firsthand source appears.