HMS Warspite wrote:
US post treaty period BB's were known to lack a good underwater protection system, as especially the South Dakota and Iowa classes had their vulnerabilities, mostly as a result of the inclining of the main belt armor, which also was build inside the hull, where an outside main protective belt as on the preceding North Carolina class offered a bit more internal space to play with. Couple with the almost paranoid stability on the post treaty USN BB's, any damaging underwater hit, causing enough list, of flooding would seriously hamper the ship, if not leading to its destruction outright. Foreign battleship designs normally did not fear much better though, except when having a much wider beam, like the Bismarck and Yamato classes, allowing a far deeper internal anti-torpedo defense system (which the Japanese for some reason did not exploit in their Yamato design)
USS South Dakota is the actual battle example. How did she fare? Against the kind of pounding that sank Prince of Wales, the SoDak survived. USS North Carolina, another example, took torpedo damage that killed a KGV and scuttled a Littorio. US design armor package choices were Panamax restricted and not because of any inherent faults in competency. Where one sees American design flaws is in the electrical system, as was also seen in the KGVs, and these once revealed in battle were quickly American resolved. US ships flooded even keel due to transverse sectioning. like the French did. British and Japanese ships because of the longitudinal compartmentation design tended to roll into the sinking condition and they turtled and went down in spite of counterflooding, so there is that design choice that could be considered by those naval architects with regard to the float bubble, reserve buoyancy and damage control that was less than optimal by American designers. British naval architects should also have paid attention to shaft alley and overall hull shock damage issues, but they did not.
So which navy's BBs were actually more vulnerable to underwater damage? The British BBs were, not the Americans. Battle results indicate these factors, not personal opinion, not guesswork, actual events and post battle damage assessments, sometimes decades after the event upon diving the British wrecks.
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Of the post treaty design BB's the ones produced by the USA were possibly the best gunboats in general, but certainly not the toughest, as they had the thinnest belt armor of all, one of the thinnest deck armor (opposing BB's of the same age had almost one inch more in general), as well and no reserve stability, mainly as a result of the lack of beam, and relatively overloaded hull. So the USN BB's did have only Yamato outgunning them, but had almost all outarmoring them, just as several decades ago Lord Fisher proposed to design the battlecruiser with the biggest guns and highest speed, at the expense of protection. Unlike opposing contemporary designs, the new breed of USN BB's was not protected against its own guns, where the opposition was designed to offer protection against a similar opposing design.
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Lots of wrong myths to correct.
Protection? What did the evidence show?
1. Yamatos were sunk by 457 kg SAPPY bombs and puny 240 kg TNT equivalent torpedoes. Their protection scheme was not too good.
2. KGVs ditto. They sank quickly to damage US ships, especially American aircraft carriers, to which the Americans did not succumb all that easily. See above remarks about compartmentation and shock and float bubble and reserve buoyancy as the key factors in a protection scheme.
3. When Japanese 35.5 cm shells bounced off USS South Dakota, it proved that despite the actual armor design defect, which was deeper than prudent face hardening of the Class A plate, it was good enough to defeat Japanese Vickers type 14/45 SAPPY shells easily. Refer to 1 and 2.
4. Again US design Panamax choices were not the result of incompetence but the result of the desire to fight off the float bubble as being the most important consideration for damage battle control and ship survivability as well as the treaty tonnage limits per unit. If the Americans could punch into their own ships that was also because the Midvale Unbreakables could also PUNCH into British and Japanese ships, INCLUDING the Yamatos as US postwar tests proved against the thickest Japanese plate. Not opinion, but actual events are the evidence. Refer to 1 and 2.
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The 2nd battle of Savo Island could have shown this, but it did not, mostly due to Japanese failures. USS South Dakota was hit only one to three times by 14 inch shell's (One officially credited, two probaable). Had the Japanese been alerted and ready for a surface engagement, Kirishima would not have needed time to change ammunition in the guns and turrets from land attack to anti shipping, which took her several minutes and use AP from start of the engagement early on. At the range the fight was fought, Kirishima's 14 inch AP round could have easily outmatched South Dakota's protective belt, inclined, or not did not matter at such close range. (even the 8 inch AP round could have done this at such ranges, though the majority of 8 inch hits were on the superstructure though)
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1. It is Second Guadalcanal, NOT Second Savo Island. The winners get to name the victory.
2. Kirishima did have her ammunition issues as described, but her shells should not have skipped off US plate even as SAPPY. US tests showed this post battle because they, the Americans, were mystified by the actual battle results and wanted to know why it happened the way it did. US SAPPY shells cracked the Class A plate as was expected. So there is that evidence for what it is worth.
3. Japanese 20.3 cm at those ranges failed against US cruisers. Refer to 2.
4. South Dakota's guns went tango uniform because of the Prince of Wales moment she had when an incompetent engineer shorted out her portside main electrical distribution and the breakers tripped and fried the bus. See above remarks about that design flaw. She was hammered while helpless. The armor and compartmentation held. Meanwhile her sister ship, the Washington shot the Kirishima full of holes, set that Kongo afire, and did it while she, Washington, Mexican hat danced through enough Japanese Type 93 fish fired at her to prove again that the Japanese incompetence first seen at Java Sea in a night brawl where torpedoes were wildly launched, willy nilly, and not effectively salvo fired, as was American practice, was not a fluke, but actually endemic to the IJN wrong way of doing things. Plus the IJN RAN after Kirishima was rearranged to suit American tastes.
5. Maneuver and shoot is also a form of protection which is important when discussing Americans and their ship design choices. British and Japanese fire control systems could not do the track solutions while dodging enemy straddles. They had to sail straight. The Americans could dodge and weave while shooting. Refer to 4 and the DEADLY results.
These are not opinions, but observed historic events.
McP.