接下来是德意战列舰水下防御的比较，均为s1炸药接触式爆炸。首先是意大利的普列赛体系，实际上在未完工的帝国上还做过S2与S3炸药的测试，不过这几次测试中S2与S3炸药的爆炸距离在15m以上，射流效应完全消失，因此并未对舰体造成多大损伤。主要看S1炸药的这次接触式爆炸，这才是对普列赛体系真正的考验。
1944年7月20日，330kg的S1在水下4m处接触式爆炸，为模拟燃油效果，在相邻液仓中已注满海水。舰体反应不剧烈（相较于S2与S3)，大约10秒后倾斜稳定在5度。损伤结果显示外部有8×8米的破洞，100.5至115.5肋骨间空仓进水，第二机舱进水（115.5至123肋骨空仓进水，但第四机舱仍保持干燥)但进水量被认为是处于可控范围内的（水泵尚可处理)。就这次结果来看，帝国号相当于抵御了1148磅的tnt，算是一个相当不错的结果。

但作为对比，德国人模拟德意志级袖珍战列舰的防雷体系，3.75m纵深（这一次测试同样也是模拟俾斯麦防雷纵深的最窄处)，40mm焊接防雷舱壁。300kg的S1炸药于水下4m处爆炸。这一次测试中舰体同样进水（焊接的防雷舱壁焊缝开裂约80mm)，根据德国人的评价（帝国那次)，进水程度应该是要严重于帝国的。也正是这一次实验，证明了焊接防雷产品的不可靠，随即又换回了更厚实的45mm铆接防雷舱壁。而在5.4m纵深，45mm铆接防雷舱壁模拟俾斯麦的水下防御，对300kg的S1炸药的接触式爆炸，实现了完全抵御，即舰体内部完全没有进水，仅防雷舱壁略微凹陷。但实际上，3.75m的纵深，40mm的焊接防雷壁，对300kg的S1炸药也一定程度上实现了抵御，因此这可能还远不是其TDS极限值（有人声称模拟的该体系成功抵御了相同当量，但以S2代替S1的接触式爆炸，但具体无法考证)。因此神乎其神的普列塞实际上可能只与俾斯麦TDS纵深最窄处相当或略优。略微差于俾斯麦舰体中部的鱼雷防御。但需要注意的是普列赛的防御纵深将近达到7米，所以我们不仅要问一句普列赛真的能算是一个很好的设计吗？

定损结果显示：100.5 至 115.5 号肋骨之间的“圆筒”（普列赛系统核心）与纵向舱壁之间的空舱进水。但 115.5 至 123 号肋骨之间（对应 第 IV 机舱）的空舱保持干燥。由于平衡注水系统（counterflooding system）中的一个焊接点失效（failure of a soldering)，导致 第 II 机舱 进水。由于没有可用的水泵且漏点难以接近，第 II 机舱缓慢进水至吃水线。评估认为这些渗漏完全在水泵的能力范围内。40 毫米厚的纵向舱壁未被击穿。中间空舱进水被归因于40 毫米板与28 毫米板连接处的渗漏。
德国人自己那个焊接ATB的确是焊缝开裂了。而至于德国人对此给予的高评价，性质类似于丘吉尔评价俾斯麦是，"世界上最伟大的战舰"，"永不沉没的海上堡垒"

the British Mark1 15 and Mark 17 airdrop torpedoes and the American Mark13 all equipped with Torpex warheads can on
It's not probable that BISMARCK's TDS was endangered from (any) air dropped torpedoes with contact fuze. The British air dropped torpedoes failed to overcome the TDS of PBB DEUTSCHLAND on a clear hit amidships abreast the engine rooms (the ATB held, although shock effects did knock out the Diesels at this instance). Deutschland also had a rivetted 45mm ATB bulkhead (although not made of Wh like the 40mm ATB of SCHEER and ADMIRAL GRAF SPEE but of low% nickel steel as in late HSF capital ships of the 1910's) and had only 2/3 the system width of BISMARCK's 45mm Wh ATB 5.4m from the hull shell. It is not unreasonable to assume that the whole TDS system of DEUTSCHLAND has a lower performance than the TDS of BISMARCK.
Or in other words, the TDS rating of BISMARCK was about 300kg S1 in contact at its narrowest sections aft and foreward, where the depth of the TDS was about as large as that of GRAF SPEE, which also resisted a 300kg charge with only 40mm Wh ATB. Amidships, the TDS rating should be expected to increase proportionally to the wider depth of the system.
S1 and S2 -while only slightly more powerful than TNT in shock effect (peak pressure wave)- can be regarded as near full aequivalents to mid-ww2 Torpex in destructive effectiveness against inboard directed TDS bulkheads through "Schubeffekt" / -the at that time poorly understood but empirically recognized jet effect.