<Li> Slow Ahead / Astern, the number of revolutions is standardized for the individual ship, and as such is unstated; </Li> <Li> Half Ahead / Astern, accompanied by an order for a specific power setting (e.g., "half ahead both engines, revolutions 1500"); </Li> <Li> Full Speed Ahead / Astern . This is reserved for emergencies, and as such the word "speed" is included to distinguish it from the other commands previously mentioned . No specific power setting is expressed, it being implicit that maximum power is required . </Li>

Where did the term flank speed come from