求问一个看书的小问题，这里一直没明白

北师大的海

看美国巡洋舰设计史里面这一段话的意思是CA2D是有13英寸35磅背板的装甲带，但是为什么前面表格里面对12寸炮的免疫区感觉不像有这么厚啊？

北师大的海

就是这段话看到的13寸装甲带，图片传得好模糊。What was hidden in these figures was the extraor-dinary cost of protection against the very efficient12-in gun.For example,CA 2D was designed with13-in belt armor on 35-lb backing,which was con-siderably thicker than that of the lowas.On the otherhand,the short range ensured against underwater-trajectory shell hits,the threat of which had causedconsiderable problems in battleship design.Modestouter limits (20,000 rather than the 30,000 yards ofbattleships)made for reduced deck armor.In a majorchange from cruiser practice,side armor was main-tained at full height for its entire length rather thanbeing stepped down fore and aft of the machineryspaces,"to gain,without excessive depth of hull,ap-propriate resistance to gunfire through armored free-board,as well as to provide a degree of buoyancyprotection which is considered essential in a ship ofthis size."That is,in the eyes of Preliminary Designthe near-battleship size of CA 2 justified changes indesign practice which in themselves increased thesize of the ship and therefore contributed to the de-feat of its concept.Splinter protection was superiorto the usual cruiser standard,except in the minimumdesign,CA 2A.

北师大的海

就是这里这个表格。是美国巡洋舰设计史的294和295页。

北师大的海

压缩了一下图片大小，就是这个13寸装甲带和免疫区没弄明白……

海上君主

同问。楼主的意思就是免疫区下界同为18千码，CA2D主装13寸+35磅（合计13.875寸），CA2E-H主装10.1寸+130磅（合计13.35寸），看起来CA2D防护应该更强一点吧？

北师大的海

海上君主 发表于 2022-5-30 18:01
同问。楼主的意思就是免疫区下界同为18千码，CA2D主装13寸+35磅（合计13.875寸），CA2E-H主装10.1寸+130磅 ...

嗯嗯是的，而且看CA2D的另外一张图纸装甲带也是19度的，等效比衣阿华还要厚，面对12寸炮的免疫区却感觉好小，总觉得有哪里不对。

伊吹

我怎么看不明白你们说的是啥，空白区是啥啊，你有疑问的是啥啊

伊吹

打漏了，是看不明白

第四弦

基本上19度倾角、18千码免疫区下界和13吋厚度里面大概有一个出错了，我倾向于是表格里面18千码的免疫区下界写错了。（当然了都是间接推测）

首先是图纸上明确标明了19度，这个出错的可能性最低；



然后是你的引文，稍微往前翻一下就能看见这么一段：

“As in cruisers, the inner edge of the desired immune zone was set at a much shorter range than in battleships, even though 12-in-gun fire would be effective at battleship ranges. The short inner-edge range was justified on the ground that a ship operating alone might well find itself engaging other cruisers at short range, particularly if weather limited visibility. In a fleet such engagements would be precluded by the presence of lighter screening ships. Thus many of the CA2 designs showed rather thick belt armor.”

18千码的免疫区下界其实跟战列舰同一水平（南达科他对16吋2240磅2520fps的下界是17.7千码），跟这段描述显然是不契合的，但如果带入13吋19度就很合适了。

最后拿sps稍微验证，10吋上下的装甲明显用不了这么大的吨位，而13吋主装也能轻轻松松捏出来……

北师大的海

第四弦 发表于 2022-6-1 16:55
基本上19度倾角、18千码免疫区下界和13吋厚度里面大概有一个出错了，我倾向于是表格里面18千码的免疫区下界 ...

哦哦！那这样看来那个18千码有可能其实是对16寸标准弹的免疫区了，感觉可能是错在这儿了。