Search found 216 matches

by JtD
Mon Sep 27, 2010 8:25 pm
Forum: Bismarck General Discussion
Topic: Bismarck and her contemporaries
Replies: 1293
Views: 128051

Re: Bismarck and her contemporaries

Funny one, really. The original chart has a discontinuity exactly at 0100. So if we were to count seconds, and to assume that Washington did not open fire before 0100:00, then it is less than 30° - because we go with the course plotted after 0100. If we consider this a typical inconsistency of histo...
by JtD
Mon Sep 27, 2010 8:09 pm
Forum: Bismarck General Discussion
Topic: Bismarck/Tirpitz = most powerfull European battleships
Replies: 249
Views: 22106

Re: Bismarck/Tirpitz = most powerfull European battleships

Other ones were dropped in a different attack, probably from a lower altitude that simply prevented them from penetrating. A fuse can get damaged by the impact, Bismarcks shell that hit PoW below the waterline was possibly defused upon hitting the water. I'd count the bomb as defeated, even though t...
by JtD
Mon Sep 27, 2010 5:42 pm
Forum: Bismarck General Discussion
Topic: Bismarck and her contemporaries
Replies: 1293
Views: 128051

Re: Bismarck and her contemporaries

alecsandros wrote: The impact obliquity is 31.5*, at least from my calculation -- arccos (cos20*) x (cos5.5*)
The result of that equation is 20.7°.

Nominal velocity at 10000yards was 1900fps, so it can be expected to not be lower than that at 8500.
by JtD
Mon Sep 27, 2010 4:51 pm
Forum: Bismarck General Discussion
Topic: Bismarck and her contemporaries
Replies: 1293
Views: 128051

Re: Bismarck and her contemporaries

So, which ones would have been stopped, which ones would not have fused? It never ceases to amaze me how people cherry pick figures that suit them, really. Feel free to contact Mr. Lundgren and ask him if he thinks if Washington opened fire with 358° true, as the chart he published and you're using ...
by JtD
Mon Sep 27, 2010 11:07 am
Forum: Bismarck General Discussion
Topic: Bismarck and her contemporaries
Replies: 1293
Views: 128051

Re: Bismarck and her contemporaries

I don't see that written down in the text, anywhere, so I'm assuming you've read that from the chart. The chart would also say that Washington opened fire at Kirishima with a bearing of 358° true, however it did with 8° true. This can also be seen in original charts. Since Washington hit, there's re...
by JtD
Mon Sep 27, 2010 9:55 am
Forum: Bismarck General Discussion
Topic: Bismarck/Tirpitz = most powerfull European battleships
Replies: 249
Views: 22106

Re: Bismarck/Tirpitz = most powerfull European battleships

Didn't a 1600lb AP bomb at about 300m/s velocity and an angle of impact of about 70° penetrate the 50+100mm arrangement on Tirpitz?
by JtD
Mon Sep 27, 2010 8:19 am
Forum: Bismarck General Discussion
Topic: Bismarck/Tirpitz = most powerfull European battleships
Replies: 249
Views: 22106

Re: Bismarck/Tirpitz = most powerfull European battleships

...If the homogenous armour has a tensile strength of greater 80kg/mm2, a de-capped shell requires considerably greater necessary velocity compared to a capped shell of equal mass, particuarly where we are talking about accutely oblique striking angles. Many examples where we have neceassary veloci...
by JtD
Mon Sep 27, 2010 8:15 am
Forum: Bismarck General Discussion
Topic: Bismarck and her contemporaries
Replies: 1293
Views: 128051

Re: Bismarck and her contemporaries

That's exactly where I got the information from. Washington started 65° off Kirishimas bow and ceased firing 85° off the stern, therefore a classic drive by shooting, with most of the damage done from a position almost exactly to the side of Kirishima. Now if you want to add vertical inclination to ...
by JtD
Sun Sep 26, 2010 11:06 pm
Forum: Bismarck General Discussion
Topic: Bismarck/Tirpitz = most powerfull European battleships
Replies: 249
Views: 22106

Re: Bismarck/Tirpitz = most powerfull European battleships

Note that 80mm+50mm=130 mm, and I seriously doubt that is coincidental. It's enterily plausible that because of de-capping and other factors touched upon that they knew that c1h/c could be raised to the point that VII>=VI, and they could attain at least 1:1 effective thickness. Actually, the only w...
by JtD
Sun Sep 26, 2010 10:57 pm
Forum: Bismarck General Discussion
Topic: Bismarck and her contemporaries
Replies: 1293
Views: 128051

Re: Bismarck and her contemporaries

OK, well according to NAaB at 8500 yds and 1952fps the nominal penetration of a USN 16/45/2700lb projectile, of UK CA armour is 20.3 inches. Ok, well, according to other calculations it is more. At 45 deg inclination, this drops to 12.4in for complete penetration and 13.9in for partial penetration ...
by JtD
Sat Sep 25, 2010 6:59 am
Forum: Bismarck General Discussion
Topic: Bismarck and her contemporaries
Replies: 1293
Views: 128051

Re: Bismarck and her contemporaries

Considering that Kirishimas unprotected superstructure fused shells, I'd say that PoW would have fused them as well.

The nominal armour penetration at that range was ~600mm, so not even somewhat increased obliquity is going to save PoW from getting the hull ripped open.
by JtD
Fri Sep 24, 2010 8:49 pm
Forum: Bismarck General Discussion
Topic: Bismarck/Tirpitz = most powerfull European battleships
Replies: 249
Views: 22106

Re: Bismarck/Tirpitz = most powerfull European battleships

Saves 30-50% if the first plate breaks up the projectile.

So when does that happen? Certainly doesn't when a 400mm shell hits a 50mm plate at 30°. Or a bomb get dropped.
by JtD
Fri Sep 24, 2010 3:54 pm
Forum: Bismarck General Discussion
Topic: Bismarck/Tirpitz = most powerfull European battleships
Replies: 249
Views: 22106

Re: Bismarck/Tirpitz = most powerfull European battleships

I'd say the 130mm turret tops would be a match for the 50+100 found over Tirpitz magazines, not for the 50+80 of the machinery. And, interestingly, with C1h = 660, C2=720 and C = 660 this is exactly what you'd get from Gerzke. Weren't the British using short fused shells that would fuse on the upper...
by JtD
Fri Sep 24, 2010 2:05 pm
Forum: Bismarck General Discussion
Topic: Bismarck/Tirpitz = most powerfull European battleships
Replies: 249
Views: 22106

Re: Bismarck/Tirpitz = most powerfull European battleships

This is a very long and technical report with some open ended conclusions, it doesn't really answer the question, was Bismarck the best? It's a detailed analysis of the strengths and weaknesses of Bismarcks armour protection. And while I don't agree with every conclusion reached, it quite well illu...