Bgile wrote:
All we know is that one technician was having troubles on Indiana in early 1943.
Your statement is all inclusive. All I know about is some problems with 5" guns in RPC. The 40mm Bofors used RPC, and they shot down a lot of aircraft. The British used it as well. How bad could the problems be?
What does this have to do with the fuse setters in the hoists? As far as I know, they were relatively trouble free.
I'm guessing that if you looked into the lives of British maintainers during the war you would find a few with serious maintenance problems to deal with. For some reason, we don't hear about them. A read of the pom-pom problems during the loss of force Z is instructive. IIRC one 8 gun mount on Repulse had one gun firing.
I know that the RN had problems with RPC as well, but also that the RPC used on the Bofors mount, which, IIRC, was derived from UK (Admiralty Research laboratory) technology used by the British Army for the Kerrison Predictor (
http://en.wikipedia.org/wiki/Kerrison_Predictor ) , did not use the USN RPC system and was pretty much free from the problems in the other USN RPC systems. I have commented adversely on the RN Hazemeyer system in the past.
If the hoists aren't working, then neither are the fuse setters...
Despite the defective ammo, Repulse's pom-poms still shot down two aircraft. Technically, PoW's CIWS was far superior, but it proved more fragile, and it failed to perform up to the same levels as it had in Aug/Sept 1941 during Operation Halberd. Why this was the case, has never been adequately explained, IMHO.
The point, again, is that it is wrong to assume that because a particular system appears to be technologically superior, that in actual service, that it was. The RN needed robust systems that could work with minimal maintenance under very adverse conditions, and it took the USN some time, which was a luxury the USN had, to work out the bugs, but the RN was in the thick of it from 1940 onward and the same kinds of problems would have been catastrophic. I'll quote from Mindell again:
However useful and innovative, this feature exceeded the limits of BuOrd’s or its contractors’ technical knowledge. The feedback loop on the Mark 37,“a previously untried closed-circuit servo,” had a stability problem: the output of the computer moved the director, which in turn affected the input to the computer. Both the computer and the power drives had time lags, so the two could push and pull each other and make the system oscillate. How these loops interacted and fed back on each other was poorly understood and caused severe problems in operations. When radar was added in the equipment was already in production, and the navy was preparing for war. The noisy, often erratic signals instigated a complete breakdown. But The stability problem in the Mark 37 was the most prominent example of a complication arising throughout naval fire control. Wherever sensitive instruments and intricate computers drove powerful servos on heavy gun mounts the systems could become unstable.“It is well known,” a 1937 report read, that “the guns, because of their enormous inertia, do not respond instantaneously to a signal from the director . . . for similar reasons the guns tend to swing too far when coming to alignment with the director after such motion, giving rise to ‘hunting’ or oscillations.” Adjustments could make these systems stable, but only at the cost of unacceptably degraded performance. A series of tests identified an “inherent weakness”in the Ford system of control and in the hydraulic speed gear with which it was used. BuOrd’s precious machines suffered from “insufficient ‘stiffness’ or ‘rigidity’ or a lack of prompt response to the director system.” Naval fire control systems, for all their precision, ruggedness, and sophistication, had run up against a problem the engineering culture could not solve: how to make a feedback loop move a large mass at high speed without making it unstable. Solving this problem required more theoretical analysis than the engineering culture of fire control could provide, so the navy turned to institutions that had developed different types of knowledge about feedback, including Bell Labs and MIT.
Mindell, David A. Between Human and Machine : Feedback, Control, and Computing before Cybernetics.