Naval History Forums

And there I was, thinking that Washington sunk Kirishima. Where did I get that from.

So, it's not 720 then?

The French chose the armour to protect the ship against bombs, mainly, not long range shell fire. Thanks for asking about the deck, indeed it appears to have been non cemented, with the turret roofs being different. Sorry.

You said C2 = 720, and that's what I used. If you need it to be it a 1000 now because 720 doesn't cut it, feel free, the Excel sheet will give you the result in no time. Richelieus cemented deck was far more effective against bombs or projectiles coming in at really steep angles than it was at defea...

This is getting tiring. You have the Excel sheet, so play with the numbers. And if you don't trust it, do your own calculations. When you do, pay big attention to the various C's, as you keep mixing them up. They are very clearly spelled out in the transcription of the Gercke interview, so there's n...

So to get from 660 to 720 you're essentially looking at the relative tensile strengths and estimate that number on your own, is that right? It's not from any report that is directly linked to Krupp armour penetration tests. It should be noted that the C=660 for homogeneous armour in the report refer...

As there are apparently no questions left, could one of you please explain to me how you arrived at the figure of C2 ~ 705...720 for Wotan hart?

For your entertainment and education I've put Gerckes formula into an Excel sheet, which you can find here:

http://www.mitglied.lycos.de/jaytdee/Compoundarmour.xls

If you have any further question, feel free to ask.

Says ADM213/915. The purpose of the space array tests was to determine the most effective arrangement and properties of the armor deck system. Tests showed that the best results come when the second deck is harder than the one above, consequently having a higher ballistic coefficient. The ratio bet...

This is not what he says on the next page. Next page says: If the coefficient (I gave) multiplied with the ratio C1h/C is larger than one, then the velocity is larger for two plates then it would be for one plate. Please note, it is C1h and C, not C2. And it's not squared. C1h is the C value for the...

Formula 6a, page 78, which the table on page 98 is based on:

(C2/C1)^2 = 1.2, as you say
e = 80/130 = 0.615

Therefore

V2/V1 = sqrt((1-0.615)^1.6 + 1.2 * 0.615^1.6) = sqrt (0.22 + 0.55) = 0.88

Not 1.07. Point out mistakes if you wish.

For Bismack and Tirpitz, V2 = 1.07xV1, and not 0.82. Says who. And more importantly, why? This is not about the torpedo protection system. You seem to have a vague representation of Bismarck's geometry. http://www.kbismarck.com/proteccioni.html The inclined portions of the second deck (turtle deck)...

What is the context of this snippet? Gercke does report that in most cases multiple thin plates result in Vnot= (square root) V1(squared) +V2(squared)+v3(squared)... but did you notice when he outlines how a two plates system can match or exceed the effective thickness of a single plate of equal su...

http://www.navweaps.com/index_nathan/Penetration_United_States.htm Deck perforation at 24000 yards for 2700pds shell fired from 16/L45 = 4.5" to 5.4", with an average of 5" = 124mm Ok, my number is against rolled homogeneous armour, qualities not stated. German decks from your source...

US empirical formula gives 124mm STS, and that is probably exaggerated. It is more likely 110-115mm. This depends on the formula, data published for the gun, based on the US formula, gives 140mm at a range of 22000m. 124mm is what the 16"/50 would do at that distance. Bismarck's minimum compou...

Made up through greater thickness. The 16" perforation of the entire deck system of Jean Bart at Dakar shows that the difference wasn't compensated. The normal perforation for that shell at 20-22km was 124mm, while the compounded thickness of JB's deck system was ~ 160mm. At 22 km it was more ...