Alberto Virtuani wrote:
Can someone confirm/correct these schemes and provide some comments about their efficiency (e.g at which distance/inclination would Montana have been immune to her own and to Yamato's guns?
Dave Saxton wrote: "Maybe it (17") represents the barbets, but they should not be at the midships cross section"
Robertson wrote: "that leaves the problem of the gain of only 1100 yds for a 3.8 in thicker belt"
RobertsonN wrote:A point about Montana's protection scheme which puzzles me. I have a copy of a document listing official IZ values for US battleships (C-BB/S1-1 of 13 July 1942) against 16 in 2240 lb shells with an MV = 2520 fps. The inner limit for BB 61 (Iowa) is given as 17600 yds and that for BB 67 (Montana) as 16500 yds. But Montana was to have had a 16 in belt, much thicker than Iowa at 12.2 in, both sloped at 19 deg. True the Iowa also has a 1.5 in outer hull, which adds only a little to the overall protection according to any of the usual formulas. There is also the possibility that the outer skin acted as a decapping layer, which would considerably increase the protection offered and indeed prevent effective penetration by intact shells. But I am sceptical that the outer skin was thick enough to reliably decap incoming shells, particularly at the obliquities related to the inner limit of the IZ. And AFAIK no historical sources or serious secondary ones ever mention decapping in this context. But that leaves the problem of the gain of only 1100 yds for a 3.8 in thicker belt. Some of the difference might come from a significantly lower quality of the thicker armor. Any other ideas?
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