The Type 23 ASW Frigate has set the gold standard in NATO for ASW capability for a generation, with its quiet DC propulsion system.  The Type 23 is shortly to be superseded by the Type 26 Global Combat Ship, using even quieter AC propulsion motors.  However, even more advanced technology is in development, that could yield even quieter and more power dense solutions.  This presentation reviews the progression of quiet ASW propulsion technology over the last 30 years and examines what can be expected from the technology of the future.