Vanguard vs. Iowa?

Historical what if discussions, hypothetical operations, battleship vs. battleship engagements, design your own warship, etc.
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José M. Rico
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Re: Vanguard vs. Iowa?

Post by José M. Rico » Thu Jul 09, 2020 3:16 am

Julien wrote:
Tue Jul 07, 2020 12:37 pm
I wrote such a long response to this that took hours to write giving armor values, effective armor at ranges, and armor penetration values showing how Iowa had the advantage in almost every scenario save for storms and the stupid site deleted it because it wanted me to sign in to post it even though I was already logged in, I've lost all willpower to respond effectively. All I'll say is that I put so much work into that response and it was just cut away by this broken site. I won't be posting on here again. That response was crafted with well over a couple hours of my time. This site can burn...
I'm very sorry to hear about that.
When writing very long messages, I suggest you save a draft of your text in your computer, so you can later "copy and paste" it to the site in case anything goes wrong.

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wadinga
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Re: Vanguard vs. Iowa?

Post by wadinga » Thu Jul 09, 2020 6:50 pm

Fellow Contributors,

I expect we have all had that frustration at one time or another, but Mr Rico is perfectly correct. I always highlight and Control-C before hitting the preview button (just in case) and if I am being really long-winded, I compose my deathless prose in a word processor and insert in the box.

Julien, don't let a little setback get you down, just keep on posting!

All the best

wadinga
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Thorsten Wahl
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Re: Vanguard vs. Iowa?

Post by Thorsten Wahl » Fri Jul 10, 2020 9:44 pm

I had the same problem several times.
It does me not prevent from writing.
Meine Herren, es kann ein siebenjähriger, es kann ein dreißigjähriger Krieg werden – und wehe dem, der zuerst die Lunte in das Pulverfaß schleudert!

Mostlyharmless
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Re: Vanguard vs. Iowa?

Post by Mostlyharmless » Sat Jul 11, 2020 1:41 pm

There is another reason for composing a message using a word processor on your computer rather than online. On many sites, anything that you write online can be stored by the website. Thus if you were to write a vicious libel against another member and then decide not to post it, the words could still be found via the site's logs and used against you.

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wadinga
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Re: Vanguard vs. Iowa?

Post by wadinga » Sat Jul 11, 2020 9:26 pm

Hello Mostly Harmless,

Good point. Having enjoyed the catharsis of typing it, there is still time to reflect that actually posting it would maybe not be such a good idea. :cool:

Just a reminder for extreme range fans, it would appear no warship has hit anything with a gun at more than 27,000yds that was not a landmass and standing still. There is apparently some suggestion about Yamato and White Plains at Samar, but there were other ships shooting from closer.

AquaDragon I am confused by
also using diseal which is not combustible is an edge
Vanguard was a steamship burning fuel oil as described above:
Machinery:
4-shaft Parsons geared turbines, 8 Admiralty 3-drum boilers, 130,000shp = 30kts (31.57kts on trials at 45,720t), Oil 4,423t..
All the best

wadinga
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Steve Crandell
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Re: Vanguard vs. Iowa?

Post by Steve Crandell » Sun Jul 12, 2020 1:30 am

Why do you think that because the longest range hit was at 27,000 yds that means it wasn't possible to hit things at longer ranges? That happened early in the war, and late war the USN practiced at ranges of over 30,000 yds. They obviously thought they could hit a battleship size target at that range. If you get a hit at that range it will probably be a hit on deck armor, which it will penetrate, potentially resulting in destruction of the target ship. Why is that not worth doing?

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wadinga
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Re: Vanguard vs. Iowa?

Post by wadinga » Sun Jul 12, 2020 10:21 am

Hi Steve,

I realize now this long range gunnery debate is a "thing" for you after reading the thread "Long Range Gunnery" commencing at
http://www.kbismarck.org/forum/viewtopi ... =36&t=2637

After reading contributions from luminaries like Brad Fischer and Bill Jurens I take the latter's observations as a good guide:
My first guess would be to multiply the table figures by 0.5, i.e. to assume about 1% hits at 30000 yards for normal target angles.
100 shells for one hit- maybe.

and I note your own estimation was at odds:
He presents a graph at the end which would indicate to me that it wasn't unreasonable to expect good results from these guns at a range of 35,000 yds. My estimate from interpreting the final graph is about 7% hits on a battleship size target at that range from hot guns, which would make such an attempt worthwhile.
However such estimations are based on extrapolations from experimental data flawed by such points as:
Target speeds were, admittedly, often somewhat slower than might be experienced in combat, especially when towed targets were being used. Offset shoots enabled the target to travel at higher speeds, but somewhat restricted the course changes permitted due to safety issues.
In other words- unrealistic. Wishing and wanting and hoping is one thing, but in real life the chances of hits are clearly diminishingly small.

Even the studies slew things to try and be encouraging.
A Naval War College study performed during World War II estimated that an Iowa Class (BB-61) battleship firing with top spot against a target the size of the German battleship Bismarck would be expected to achieve the following hit percentages.
Range Percentage hits against a broadside target Percentage hits against an end-on target Ratio
10,000 yards (9,144 m) 32.7 22.3 1.47:1
20,000 yards (18,288 m) 10.5 4.1 2.56:1
30,000 yards (27,432 m) 2.7 1.4 1.92:1
By choosing to consider an end-on target the really difficult problem of estimating inclination accurately neatly disappears. Battleships fighting each other would be on nearly parallel courses to unmask all batteries. 10 degree error in estimating inclination means that shell travelling for 70 seconds at a ship which has moved a kilometre is heading for the wrong place. A hit would be only a result of inaccuracy/dispersion. Luck.

Back in the real world when bombarding Japanese static land targets with an area much larger than a battleship:
TU 34.8.2's bombardment began at dawn on 15 July. The three battleships fired 860 16-inch (410 mm) shells at the city from a range of 28,000–32,000 yd (26,000–29,000 m). Aerial observation and spotting of damage was made difficult by hazy conditions, and only 170 shells landed within the grounds of the two plants.
from Wikipedia

All the best

wadinga
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Re: Vanguard vs. Iowa?

Post by Steve Crandell » Sun Jul 12, 2020 1:51 pm

Why do you think a ship could get a hit at 27,000 yds early war and it wasn't possible to get one at 30,000 yds late war? Range determination was much more accurate late war. If you could see the target, you could get accurate bearings. Given accurate range and bearing, you can get target inclination computationally. The target is not going to maneuver in such a way as to make much difference in a couple of minutes and still get out of the salvo pattern. For one thing, that would make it's own gunnery more difficult.

Bill Jurens had a number of plots in his and Fisher's article in Warship International which superimposed Yamato on salvo patterns from US practice shoots. There were hits. Having said that, Bill hasn't stepped in here, so at this point I'm going to give up. I don't want to put words in his mouth and his silence here speaks volumes.

Apparently accurate shooting was a lost art and what was done in the early war was impossible to repeat or improve with better technology. Everyone but me seems to agree.

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Re: Vanguard vs. Iowa?

Post by wadinga » Sun Jul 12, 2020 6:42 pm

Hi Steve,
his silence here speaks volumes
Well.............. he might actually have other things to do, gardening, walking the dog or maybe conducting a search for another missing battleship somewhere. :D

I think we should consider a number of factors. Shot dispersion gets worse the further away the target. Salvo spread is therefore bigger. No progress on that during the war.

The steeper the angle of fall the smaller the danger space gets. If the shells were able to fall vertically it would just be the deck plan.

Radar range accuracy is also somewhat dependent on distance and is usually represented as a percentage, bigger range bigger error, and it is not the range now that matters but in 75 seconds or so. Retrospectively discovering inclination (ie course steered) from averaged ranges takes quite a while and assumes the friendly opposition steers a steady course. Manoeuvering certainly doesn't exactly help your own shooting, but your gyro tells you where you are heading, you have a speed log and the F/C works out what that does to the range, so it hurts the enemy more than you.

The long range gunnery efforts were all stern chases. Glorious was running for her life ie low rate of change of distance and low change of azimuth ie low deflection corrections required. Guilio Cesare, Nowaki and even White Plains ditto.

The 1945 example. There was no benefit in getting closer to Japanese land targets than one needed to, but even with aerial spotting the preference was not absolute maximum range and results even then were not exactly outstanding, considering the targets were standing still. Some other shoots went up to 34,000 yds but again results were not great.

I agree that you are perfectly correct to say there must have been some improvement during the course of the war, but there are limitations on what "dumb" shells can do, and it just gets worse with range, and not linearly. If the Iowas really had nuclear "Katie" shells after the war they didn't need to hit the target anyway and the further away the better. However Tomahawk and Harpoon when they became available with terminal guidance are better yet.

I give a certain commander operating in very bad weather conditions, my last word
The Bismarck turned north, steaming about 12 or 14 knots. We kept turning in and out to confuse the enemy range-takers, all the while closing the range rapidly. The Admiral [Tovey] kept on saying: ‘Close the range; get closer; get close. I can't see enough hits!’ And so we closed the range.
All the best

wadinga
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Re: Vanguard vs. Iowa?

Post by Bill Jurens » Sun Jul 12, 2020 7:40 pm

I have not been following this thread particularly closely, and it seems to be developing rather rapidly. I am not sure exactly what opinions are wanted here, but if I get the gist of things correctly, I think the question is whether or not accurate gunnery could be achieved at quite large ranges. The short answer, at least in the USN is 'yes', especially after Radar ranging became common.

My data reflects gunnery experience and expertise obtained during my participation in the USN gunnery improvement program in the 1980's, a reading of the actual target practice reports conducted from 1925 or so on, often deliberately conducted at very long ranges, and a variety of SECRET level documents prepared by the Princeton University Applied Mathematics Panel mid-to-late WWII. Coupled, of course, to various documents used to create and conduct the USN Naval War College Maneuvering Game simulation.

Hits at long range might not be expected to be common, but -- as was demonstrated in a number of actions -- even a single hit, particularly a 'first hit' at long range -- could shift the balance of power quite dramatically. The idea that long range hits were so unlikely as to be of little-to-no tactical consequence is, in my opinion, not easily justified.

I would be glad to comment further, in response to specific comments and questions.

Bill Jurens

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Re: Vanguard vs. Iowa?

Post by Steve Crandell » Sun Jul 12, 2020 8:49 pm

Wadinga:

I believe you misinterpreted the results on one of your charts. It's actually more difficult to hit an end on target because a dispersion pattern is an elipse, and a small error in bearing can cause the target to be outside the pattern. A target on a parallel course is therefore easier to straddle. The Baron in his Bismarck book mentioned that their opening salvo was usually "on" for line and range had to be adjusted. Of course, a straddle on an end on target is more likely to achieve a hit.

West Virginia's performance at Surigao Strait was better than that of the British ships at Denmark strait, and West Virginia was shooting at night. West Virginia was firing full salvos, which make it easier to determine MPI on a radar display than with half salvos. When time of flight gives you the time to load all of your guns before the next salvo, there is little reason not to do that.

Shooting at an industrial target is a completely different problem. First, as mentioned in your post, it was difficult to spot because of haze. Radar would have been useless for spotting corrections, whereas at sea it's much easier because your target is on a flat plane and you are able to observe your MPI on radar. Also, one hit on an industrial target is extremely unlikely to destroy the factory.

As mentioned previously, one hit can be very significant if it penetrates the citadel armor. Massachusetts achieved a hit on Jean Bart's 6" magazine that could have been very significant had there been ammunition there.

Bill:

What percentage chance do you think an Iowa class battleship would have to hit a battleship size target at 30,000 yds? 35,000 yds?

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Re: Vanguard vs. Iowa?

Post by wadinga » Mon Jul 13, 2020 1:30 am

Hi Steve,
If you could see the target, you could get accurate bearings.
It's actually more difficult to hit an end on target because a dispersion pattern is an elipse, and a small error in bearing can cause the target to be outside the pattern.
Aren't these observations mutually exclusive?

I actually agree about bearing being easier to determine, but the fact that the shape of an end on target and a longitudinally extended ellipse are much the same shape is IMHO irrelevant.
Of course, a straddle on an end on target is more likely to achieve a hit.
Here I don't agree. A hit on a side-on target includes its whole deck plan plus all the "shadow" area on its far side developed by its hull and superstructure depending on the angle of fall, whereas most of the shadow falls within its deck plan for an end-on target, the latter is actually considerably smaller square area and thus harder to hit. Stern chase hits or near hits or worthwhile efforts to get hits (like Nowaki) depend as I mentioned on small differences in rate of change of distance and of bearing.

https://ibiblio.org/hyperwar/USN/ships/ ... rigao.html

The Surigao Strait ambush was the next best thing to a stern chase. WV action report says radar tracked the target from 03:10 until open fire at 03:52. 40 whole minutes to determine speed and analyze target manouevring. WV still only opened fire at 22,800 yds. If they had been confident at hitting at much longer ranges they should have ordered the DD's and PT boats out of the way. They were worried about wasting ammunition.
Range patterns were noted to average about 300 yards.
They knew this ecause they were getting good splash returns at that range. Whether they would have got good returns at 30,000+ yds and how big the dispersion would have been is questionable.

"Haze" looks like a good excuse to me. Air spotting should have produced better results.

Holland's ships weren't getting radar tracking for 40 minutes, had hardly any range data and a high rate of change of range. Most of the hits on PoW at Denmark Straits were immaterial. Expending say 100 shells to get a single glancing blow on, say Bismarck's boat, would have been a poor result in a long range bombardment. A lot of the target isn't citadel and that one hard-earned hit might be somewhere immaterial. Many shells didn't even explode.

BTW Jean Bart was tied to Africa- which wasn't moving.

All the best

wadinga
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Re: Vanguard vs. Iowa?

Post by Steve Crandell » Mon Jul 13, 2020 3:04 am

Hi Wadinga,

You can have accurate bearings on any target and still have an end on target be a more difficult target. Why is that mutually exclusive?

When you have a target that is 30,000 yds away, there is very little "shadow" to consider, because of the angle of descent. This is especially true of the USN 16" AP. The chance of hitting vertical armor is almost nil. The citadel is there to protect magazines and engineering. A citadel penetration has a good chance of hitting one of those areas. The hit on Jean Bart is an example of a citadel penetration and the fact that she was pierside is irrelevant. It was a hit. The same hit in the middle of the Atlantic would also have entered the magazine. That was my point, not the difficulty of hitting the target, which is greater if the target is moving.

West Virginia probably had a good fire solution within a minute or so of acquiring the target. I read the Tully book and I don't remember why they waited until relatively short range to open fire. You said "They were worried about wasting ammunition". Is that a fact, or supposition? It may have been to allow the Mark 3 equipped ships to acquire the target. It is true that the battleships there were primarily equipped for shore bombardment, unlike ships ready for antiship combat, who customarily carried a very high percentage of AP. I think Massachusetts had almost if not all AP. That would be enough for 100 full salvos.

Dispersion percentage is the same at 30,000 yds as it is at 10,000 yds. Obviously pattern size increases with range, bu it's a function of physics and it's linear. The Mark 13 was capable of marking 16" AP splashes at 30,000 yds or more. IIRC they were about 150 feet high. AP was easier to spot than HC.

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Re: Vanguard vs. Iowa?

Post by Bill Jurens » Mon Jul 13, 2020 4:30 am

Steve Crandall wrote:

"Bill: What percentage chance do you think an Iowa class battleship would have to hit a battleship size target at 30,000 yds? 35,000 yds?"

For a battleship-sized target, at 30,000 yards, estimates were 2.7% for Top Spot, 3.5% for Plane Spot, and 3.4% for Radar Spot.
There are, officially, no numbers for 35000 yards, but for 34000 yards, the equivalent values are 1.7%, 2.2%, and 2.1% respectively.

These are for engagements at 90 degree target angles. For a target angle of 60 degrees, multiply by about 0.9, for a target angle of 30 degrees multiply by about 0.76, and for a target angle of 0 degrees multiply by about 0.57.

This from SECRET report AMP Report No. 79.2R of the Statistical Research Group, Applied Mathematics Panel, dated July, 1944.

The Naval War College seemed to feel these figures, taken from target practices, were a bit on the optimistic side, and -- as I recall -- suggested multiplying these values by about 0.5 to reflect actual naval combat conditions.

Bill Jurens

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