budden@manta.nosc.mil (Rex A. Buddenberg) (05/08/89)
From: budden@manta.nosc.mil (Rex A. Buddenberg) Keyword: Re: Iowa Maneuverability Twin screws do not have shafts locked together. The primary reason for twin screws (or 3 like icebreakers or 4 like BBs) is survivability through redundancy. Using a single reduction gear would introduce a single point of failure. Backing down on the inside shaft(s) in a turn certainly cuts the turning radius -- all the way to 0 if you want to. Trouble is that you kill your way when you do and in WWII, tactical speed under fire still meant a lot. So if you see a BB turning inside a DD radius, the DD is probably using 5 degrees rudder. BBs were often used in the Pacific as ainti-air batteries close to the carriers. So both would be inside the escort screen, but the main battery would not be in action at all; there's enough real estate on deck to put lots of 3 and 5" guns to pop away at aircraft. Picture the BB conning officer sticking a few hundred yards away from a CV in a hot fight with both at 30 knots. Rex Buddenberg -------