In US submarine service when we had twin screw submarines, running the propeller shafts in opposite directions was called "a twist." Ranier is correct. In my experience it was used almost exclusively in tight maneuvering situations in harbor to turn the boat. Engineering plant wise on US diesel-electric boats it was simple to do and was accomplished by the port and starboard controllerman shifting a couple of levers and turning voltage restats. The load put on the diesel engines was determined by the "bell order" 1/3, 2/3, standard, full, flank. It was always accompanied with a full over rudder.

The most difficult submarine docking I experienced was in Hong Kong in 1962. We were trying to maneuver into our berth inside the basin at the Royal Navy Dockyard. 142 bells from passing the sill to all stop finished with engines. The senior controllerman told me they couldn't keep up with the propulsion orders from the conn and were always one or two orders behind. There were several "twist" combinations ordered along with having number 1 mooring line on a bollard on the pier to twist against. The Brits were impressed with our skippers ability to maneuver and tie up a 311 foot fleet snorkel boat in the basin without a pusher boat.

Patrick Meagher TMC(SS) USN Retired