Washington

Historical what if discussions, hypothetical operations, battleship vs. battleship engagements, design your own warship, etc.
alecsandros
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Re: Washington

Postby alecsandros » Sat Jul 21, 2012 8:32 pm

dunmunro wrote:
PE's guns have approximately the same ballistics as the RN 14", at 25K yds or less. The 20.3cm was a very high velocity, flat trajectory gun.


The angle of descent is consistently lower for the British gun, for all ranges the battle was fought. Thus, danger space is consistently higher.


http://www.navweaps.com/index_nathan/Pe ... ritain.htm
http://www.navweaps.com/index_nathan/Pe ... ermany.htm

Descent 14000 - 24000 yards
British 14"/L45
9.4 - 22 degrees descent.
German 8"/L60
10.0 - 28.8 degrees descent

Larger projectiles behave better at medium to long ranges (they are more stable in flight), and a battleship is a much more stable gun platform than a heavy cruiser.

Pandora
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Re: Washington

Postby Pandora » Sat Jul 21, 2012 8:39 pm

lwd wrote:
Pandora wrote: but the fact is that PoW was extremely lucky with her shooting considering she never got the correct range with her target.

I don't think that statement is correct. The fact that she got 3 hits is rather a good indicator that it isn't. As for luck that cuts both ways.

3 straddles and 3 hits, that is what I call luck. it could very well have been 3 straddles and just one hit or no hits at all.

lwd wrote:
Pandora wrote:the problem is that PoW took so long to get the first straddle for whatever reasons. even if you are using optical means only, needing 6 salvos to get a straddle vs a target on a steady course under good visibility... well it is not good.

Of course the visibility form PoW position wasn't really well described by "good" was it? Furthermore the probability of getting a straddle is impacted significantly by the number of rounds fired. For instance even if you have the range perfectly if you are firing 2 guns you will only straddle half the time. With three guns it's still only 75% of the time and as I said that's with perfect range.

that is my perception that PoW never got the range.
what about with 5 guns?

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Re: Washington

Postby alecsandros » Sat Jul 21, 2012 8:40 pm

dunmunro wrote:When I say "linkage" I mean mechanical problems with the shell feed system, which is exactly what is being described in the above quote.

They were turret problems, and catalogued as such in PoW war log.

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Re: Washington

Postby Pandora » Sat Jul 21, 2012 8:42 pm

Dave Saxton wrote:The Baron wrote that he obeyed the order to survey Norfolk and and Suffolk by using his optical director. The optical director was a persiscope like device. I studied some Denmark St. photos of Bismarck in action and it appears that the aft optical rangefinder, which the radar antenna was mounted to, was aimed at Hood or Prince of Wales throughout. This is a strong indication that the aft radar was being used to range the enemy battleships, because it was not being used to range the enemy cruisers.

The aft range finder and the foretop range finder are always aimed in the same direction, but not the forward (conning tower) range finder in the Denmak St. photos. Seperate FuMO27 radars could be tied together and operated as one unit, using single Central Impulse Geraete, Z Geraete, and Summer. They may have been doing this. After the battle the foretop rangefinder and the aft range finder remain aimed on the same coordinants, which varies from photo to photo indicating that they are going around and around together through a 360* arc.


The most forward radar antenna is not operating, or at least not operating in concert with the other two. It remains aimed directly aft in several post Denmark St. photos. This may be an indication that the conning tower radar was the one knocked out. If the foretop radar was knocked out as well it may have been brought back online by tying it to the aft radar. Some survivors talking amongst themselves, but secretly monitored by the British, said that the faulty radar was repaired by late on 24th.

It's likely that the radar knocked out was the forward (conning tower) set as Luetjens used that term in his language. He may have wanted the foretop radar to use against the shadowing cruisers and not having the use of the most forward radar he needed the Prinz Eugen to use its radar to survey ahead. Hence the change in position.

I can not see the direction the after rangefinder is pointing at the Denmark strait very well in teh photos, but what you said makes sense to me , thanks.
still some unanswered questions.

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Re: Washington

Postby Pandora » Sat Jul 21, 2012 8:45 pm

dunmunro wrote:PE output:
"Total 184 possible shots Actually fired = 157" = 85% output. If we assume 8 hits, then we have a 5.1% hit rate, or less than PoW, and PE had the benefit of radar ranging.

yes, but what matters is the number of straddles not the actual hit rate. and I dont think PE was as lucky as PoW to get hits with every straddle.

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Re: Washington

Postby Pandora » Sat Jul 21, 2012 8:48 pm

Dave Saxton wrote:Staddles tell us how good the shooting is. Hit % mainly tells us how lucky or unlucky.

EXACTLY MY POINT! :D :ok:

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Re: Washington

Postby dunmunro » Sat Jul 21, 2012 8:59 pm

alecsandros wrote:
dunmunro wrote:
PE's guns have approximately the same ballistics as the RN 14", at 25K yds or less. The 20.3cm was a very high velocity, flat trajectory gun.


The angle of descent is consistently lower for the British gun, for all ranges the battle was fought. Thus, danger space is consistently higher.


http://www.navweaps.com/index_nathan/Pe ... ritain.htm
http://www.navweaps.com/index_nathan/Pe ... ermany.htm

Descent 14000 - 24000 yards
British 14"/L45
9.4 - 22 degrees descent.
German 8"/L60
10.0 - 28.8 degrees descent

Larger projectiles behave better at medium to long ranges (they are more stable in flight), and a battleship is a much more stable gun platform than a heavy cruiser.


PoW records the range as 15k yds or less at the close of the action.

PoW/PE/Bismarck/Bismarck range table, angle of fall ( http://www.navweaps.com/Weapons/WNGER_15-52_skc34.htm )
6.0/5.4/5.8/~5.5 = 10k yds/ 2k yds intervals.
7.7/7.7/7.3
9.4/10/8.8
11.7/12.3/12.4/10.4
14.1/16.2/14.4
16.5/20.1/16.5/
19.3/24/19/16.4 = 22k yds

There not going to be substantial difference, but then again Bismarck has flatter tragectory than PoW...

lwd
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Re: Washington

Postby lwd » Sun Jul 22, 2012 3:31 pm

Dave Saxton wrote:... Bismarck's and Prinz Eugen's shooting at Denmark St. was superior to Washington's and South Dakota's shooting east of Savo Island.

This part is not so clear at least as far as Washington goes. It's not known just how many hits she got. Then the problem of just how you define "shooting" if the radar reports a false target for instance how does that count?

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Re: Washington

Postby lwd » Sun Jul 22, 2012 3:35 pm

alecsandros wrote:
dunmunro wrote:
Turret problems had nothing to do with the reductions in output up to Salvo 18; reductions in output to that point were caused by linkage problems and errors in drill.

No.

"[i]B - Events during the First Action"
..

When you quote something it's good manners and good policy to at least give the source (if the quote is extensive enough not doing so may violate copyright provisions for instance) and most boards make it part of their requirements to do so. I suspect this is from:
http://www.hmshood.org.uk/reference/off ... 09guns.htm
but there could be other sources and they might be of interest to some in the group.

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Re: Washington

Postby lwd » Sun Jul 22, 2012 3:54 pm

Pandora wrote:
lwd wrote:
Pandora wrote: but the fact is that PoW was extremely lucky with her shooting considering she never got the correct range with her target.

I don't think that statement is correct. The fact that she got 3 hits is rather a good indicator that it isn't. As for luck that cuts both ways.

3 straddles and 3 hits, that is what I call luck. it could very well have been 3 straddles and just one hit or no hits at all.

Or it could have been even more hits and/or more straddles. If she wasn't close to on 3 hits becomes pretty improbable not impossible but the larger the numbers the more the odds are against a string of improbable events.
lwd wrote:
Pandora wrote:the problem is that PoW took so long to get the first straddle for whatever reasons. even if you are using optical means only, needing 6 salvos to get a straddle vs a target on a steady course under good visibility... well it is not good.

Of course the visibility form PoW position wasn't really well described by "good" was it? Furthermore the probability of getting a straddle is impacted significantly by the number of rounds fired. For instance even if you have the range perfectly if you are firing 2 guns you will only straddle half the time. With three guns it's still only 75% of the time and as I said that's with perfect range.

that is my perception that PoW never got the range.

Then how do you explain the hits, straddles, and near straddles?
what about with 5 guns?

Then you would fail to straddle about 6% of the time. However it's worth noteing that according to:
http://www.hmshood.org.uk/reference/off ... 09guns.htm
PoW fired 18 salvos and 55 rounds that works out to just a bit over 3 rounds per salvo. Furthermore her first salvo was with 6 guns and her second with 5 I believe. If you take out these two ranging salvos then we have 16 salves and 44 rounds which is 2.75 rounds per salvo. The implication is clear she could have had a good range and still not straddled on a number of occasions. It's even possible that one or more of the hits were on salvos that didn't straddle.

Wm Jurens

Re: Washington

Postby Wm Jurens » Sun Jul 22, 2012 7:11 pm

Alecsandros wrote:

"Larger projectiles behave better at medium to long ranges (they are more stable in flight)..."

This is an interesting statement. Could you elaborate, please, regarding your understanding of the relationship between projectile stability and caliber?

Thanks in advance...

Bill Jurens.

Pandora
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Re: Washington

Postby Pandora » Sun Jul 22, 2012 8:09 pm

lwd wrote:
Pandora wrote:3 straddles and 3 hits, that is what I call luck. it could very well have been 3 straddles and just one hit or no hits at all.

Or it could have been even more hits and/or more straddles. If she wasn't close to on 3 hits becomes pretty improbable not impossible but the larger the numbers the more the odds are against a string of improbable events.

or it could have been anything but the fact is that it was 3 straddles and 3 hits.

lwd wrote:Of course the visibility form PoW position wasn't really well described by "good" was it? Furthermore the probability of getting a straddle is impacted significantly by the number of rounds fired. For instance even if you have the range perfectly if you are firing 2 guns you will only straddle half the time. With three guns it's still only 75% of the time and as I said that's with perfect range.

that is my perception that PoW never got the range.

Then how do you explain the hits, straddles, and near straddles?

good luck maybe?
I dont know of any "near straddles", just 2 straddles + 1 other probable resulting in 3 hits, total salvos 18.

lwd wrote:
what about with 5 guns?

Then you would fail to straddle about 6% of the time. However it's worth noteing that according to:
http://www.hmshood.org.uk/reference/off ... 09guns.htm
PoW fired 18 salvos and 55 rounds that works out to just a bit over 3 rounds per salvo. Furthermore her first salvo was with 6 guns and her second with 5 I believe. If you take out these two ranging salvos then we have 16 salves and 44 rounds which is 2.75 rounds per salvo. The implication is clear she could have had a good range and still not straddled on a number of occasions. It's even possible that one or more of the hits were on salvos that didn't straddle.

ummm, getting hits without straddling the taget, that is what I call good luck! :D
Last edited by Pandora on Sun Jul 22, 2012 8:24 pm, edited 2 times in total.

alecsandros
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Re: Washington

Postby alecsandros » Mon Jul 23, 2012 10:30 am

Wm Jurens wrote:
This is an interesting statement. Could you elaborate, please, regarding your understanding of the relationship between projectile stability and caliber?

Thanks in advance...

Bill Jurens.

I think it's pretty self explanatory.
An obvious empirical example comes from GKDOS100, where shell with larger caliber give smaller dispersion at longer range than their smaller caliber cousins. Assuming same gun and mount characteristics, the obvious explanation is shell trajectory - and the way it is influenced on the way by the external ballistics variables...

And I have a distinct feeling of Deja Vu. Have we discussed this before ?

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Re: Washington

Postby alecsandros » Mon Jul 23, 2012 1:51 pm

lwd wrote:PoW fired 18 salvos and 55 rounds that works out to just a bit over 3 rounds per salvo..

NO.

21 salvos and 59 rounds.
Last edited by alecsandros on Mon Jul 23, 2012 1:54 pm, edited 1 time in total.

alecsandros
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Re: Washington

Postby alecsandros » Mon Jul 23, 2012 1:53 pm

dunmunro wrote:
PoW/PE/Bismarck/Bismarck range table, angle of fall ( http://www.navweaps.com/Weapons/WNGER_15-52_skc34.htm )


Bismarck's shells are not of concern, as your above statement was about Prinz Eugen.

Ranges below 14000y are irrelevant, as the battle was not fought at those ranges.


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