Who won?

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Bill Jurens
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Re: Who won?

Post by Bill Jurens » Mon Jul 27, 2020 2:03 am

Thanks, Thorsten. I remain, very respectfully, skeptical...

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Thorsten Wahl
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Re: Who won?

Post by Thorsten Wahl » Mon Jul 27, 2020 11:16 am

Bill Jurens wrote:
Mon Jul 27, 2020 2:03 am
Thanks, Thorsten. I remain, very respectfully, skeptical...

Bill Jurens
Can imagine this as "learned" artilleryofficer.
Meine Herren, es kann ein siebenjähriger, es kann ein dreißigjähriger Krieg werden – und wehe dem, der zuerst die Lunte in das Pulverfaß schleudert!

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wadinga
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Re: Who won?

Post by wadinga » Mon Jul 27, 2020 1:13 pm

Fellow Contributors,

They were not the only ones......

From the RN Progress in Gunnery 1939
89. The limitations of the method of correcting for canted trunnions, described in C.B. 3001/36, page 90, have been disclosed in practice firings during the year, and proposals have been put forward for additional equipment to enable this correction to be applied more accurately and with less lag.

These proposals will be fully met by the cross-levelling gear which will go into production shortly, and in the meantime temporary additions to fire control equipment cannot be contemplated.
I guess if anybody anywhere had ever managed to hit anything at more than 27,000yds we would know whether this was successful.

Bill has previously mentioned the limitations imposed by the use of towed target sleds, principally with regard to their unrealistically slow speeds and lack of manouevring and the difficulty of extrapolating realistic hit possibilities out at very long ranges from the more modest ranges at which navies normally chose to expend their very expensive reserves of training ammunition. It might be that it was a 1% chance out at 35,000 yds, but then it might not. It might be 0.1%. Several navies used radio controlled target battleships to get more realistic training, and perhaps more a realistic assessment of shell performance on and after impact.

In the RN Progress the C-in-C Home Fleet says:
It is hardly an unfair criticism to say that in the last ten or fifteen years, every time that the Gunnery results over a period have not shown improvement, some squadron or other has suggested a new form of spotting rules in the hopes of getting better hitting results.

(iii) It would not appear that the many changes in the spotting rules have had much effect on the hitting results. On the other hand, the frequent changes in the rules have undoubtedly caused uncertainty in the minds of control officers and have certainly tended to distract the latter’s attention from the real problem which has to be solved if good hitting results are to be obtained, i.e.:-

“Keeping the inclination of the enemy correctly.”

(iv) This is the crux of the whole question of hitting the enemy, and no amount of “trending” or any other form of spotting rule will produce good hitting results if the rate keeping is bad.

(v) There is no getting away from the fact that in spite of improvement in material we have made very little if any improvement in inclination results from 1918 to the present day. This points to faulty methods.
A table later on indicates that inclination estimates, even at the modest ranges used, were frequently 20-30 degrees out, and I personally suspect that estimates were worse for inclinations close to right or left 90 degrees rather than those of 0 and 180 which are the only ones with no ambiguity. (OK a binary one) :D

Sydney against Bartolomeo Colleoni was a 17-20,000yd stern chase gunnery success www.world-war.co.uk/sydney_story.php3

Norman Friedman's Naval Firepower mentions pre-war French experiments with ranges up to 28,000yds but nothing about results and frustratingly doesn't appear to mention the Iowa class experience (surely the zenith of US fire control) efforts against Nowaki.

Tsushima is an example of a short range action with plenty of hits and important functions hidden behind armour relying on its protection.

Later on there was a proliferation of vulnerable (and dangerous) equipment outside of the citadel, ie rangefinders, radar, spotting and gunnery control equipment and personnel, fuel-filled spotting aircraft, deck mounted unarmoured torpedoes and the desire of senior command to have a better view and hence situational awareness by abandoning the weighty conning tower designed for their preservation. When fighting at those ranges where the guns have a good chance of hitting, guns win because a lot of assets are unprotected. In the real world, early loss or damage to these unarmoured extraneous assets puts one side at a great disadvantage and relatively toothless if a toe-to-toe pounding match ensues. PoW's Compass Platform, Bismarck's fire control, South Dakota's electrics and Guilio Cesare's air intake are all examples. The first and last were in a position to escape from the fight, SoDak had a buddy, but Bismarck had neither.

All the best

wadinga
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Steve Crandell
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Re: Who won?

Post by Steve Crandell » Mon Jul 27, 2020 6:16 pm

I believe it was fairly common for US fast battleships to perform gunnery practice at ranges over 30Kyds.

Thorsten Wahl
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Re: Who won?

Post by Thorsten Wahl » Mon Jul 27, 2020 8:32 pm

Steve Crandell wrote:
Mon Jul 27, 2020 6:16 pm
I believe it was fairly common for US fast battleships to perform gunnery practice at ranges over 30Kyds.
Do you have impact patterns of 9 gun salvos at this distance?
Meine Herren, es kann ein siebenjähriger, es kann ein dreißigjähriger Krieg werden – und wehe dem, der zuerst die Lunte in das Pulverfaß schleudert!

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wadinga
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Re: Who won?

Post by wadinga » Mon Jul 27, 2020 10:02 pm

Hello Thorsten,

I have just dug out Bill and Brad Fischer's titanic splendiferous two-part article from Warship International and will be keeping my head below the parapet until I understand all/some/any :shock: of it.

They do present many examples, including one of the "finer practices from the collection" showing salvo patterns from USS North Carolina at ranges in the region of 32,300 yds during an offset shoot with USS Washington as target. Multiple hits were estimated to have been made on a nominal battleship sized target from only 11 partial salvoes. Good shooting indeed! Perhaps Bill could be induced to reproduce an example.

Although I think it fair to say the majority of examples shown, even from late WWII, appear to be from practices at considerably shorter ranges, 22,600 yds being a popular value. Unfortunately many salvoes recorded are less than 9 shots, realistically I suppose because of economics/ gun wear.

All the best

wadinga
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Bill Jurens
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Re: Who won?

Post by Bill Jurens » Wed Jul 29, 2020 12:07 am

Often, small salvos were used because it made spotting more difficult -- it's harder to accurately spot a four-gun pattern than a nine-gun pattern, and the target practices were often for training purposes. Sometimes shorter ranges were employed with reduced charges, which essentially made a 24000 yard range look like a 35000 yard range with much less equivalent wear on the guns. It's difficult to generalize...

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Re: Who won?

Post by Steve Crandell » Wed Jul 29, 2020 6:21 am

Thorsten Wahl wrote:
Mon Jul 27, 2020 8:32 pm
Steve Crandell wrote:
Mon Jul 27, 2020 6:16 pm
I believe it was fairly common for US fast battleships to perform gunnery practice at ranges over 30Kyds.
Do you have impact patterns of 9 gun salvos at this distance?
I believe there is a formula based on known average gun dispersion for the weapons in question in the Jurens/Fischer series, but I don't have it to hand at the moment.

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Re: Who won?

Post by Bill Jurens » Wed Jul 29, 2020 5:30 pm

There are a number of rule-of-thumb formulas for this. At normal battle ranges, these allow doing the problem in one's head. For 9 guns and U.S. guns, expected pattern size is range is typically around 1.8-2.0% of range. At long ranges where gun alignment doesn't really matter much, provided the interior ballistics is good, this is almost independent of the type of guns in use.

In addition to my papers written with Mr. Fischer, you can also check out "The Evolution of Battleship Gunnery in the U.S. Navy, 1920-1945" in Warship International, probably around 1989 or so.

Bill Jurens.

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wadinga
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Re: Who won?

Post by wadinga » Thu Jul 30, 2020 12:01 am

Fellow Contributors,

That article is in Warship International Number 3 1991. I am enjoying studying it again now, along with the later one.

I have been an INRO member for many, many years and have learned a great deal thanks to the heroic and selfless efforts of the Editorial and Production team including Bill Jurens. :clap: :clap: :clap:

All the best

wadinga
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paul.mercer
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Re: Who won?

Post by paul.mercer » Thu Jul 30, 2020 9:30 am

Gentlemen,
A fascinating subject although a bit too complex for my limited (very!) knowledge on the subject.
Are we saying that with the improvements to radar and range finding in the latter years of WW2 that it was possible to fire out t a range of 35000 yards with a reasonable chance of hitting the target? If this is so it brings me back to another topic where I asked about penetration and you kindly explained to me in detail. it was about the penetration of a one ton bomb against a one ton shell, if I am correct in my understanding of the replies the answer being that a shell would be falling at an angle but the bomb would be falling almost vertically and was more likely to penetrate the amoured deck. My question is this, presumably if a ship is firing at maximum range, the guns would be at maximum elevation and at a range of 30-35000 yards surely the shell would be falling almost vertically, like the bomb and therefore very likely to penetrate the deck armour.
While on the subject, I believe some of the Iowas were refurbished for the Vietnam and first Gulf wars with a considerable amount of dollars being spent on modernising the radar and fire control systems, so would that have enabled them to accurately fire at greater distances.(like 35000 yards) Does anyone have any information at what ranges they were firing at in those two wars?

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wadinga
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Re: Who won?

Post by wadinga » Thu Jul 30, 2020 3:50 pm

Hello Paul,

You might choose to visit Navweaps http://navweaps.com/Weapons/WNUS_16-50_mk7.php in order to find for yourself information like this:
35,000 yards (32,004 m) 12.97" (329 mm) 8.48" (215 mm) 1,556 fps (474 mps) 36.27
That is 36.27 degrees angle of fall. Even at the most extreme 42,345 yds it is only 53.25 degrees.

That nowhere does it approach 90 degrees to the horizontal.
Are we saying that with the improvements to radar and range finding in the latter years of WW2 that it was possible to fire out t a range of 35000 yards with a reasonable chance of hitting the target?
Further perusal of the Navweaps location will suggest maybe 2.7% hits at 30,000 yds and under actual combat conditions this estimate
would be on the optimistic side
The Bill Jurens and Brad Fischer papers of which we speak go to immense detail in attempting to answer a question like yours. Recently Bill has answered thus on another thread:
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.
So at 34,000 yds, even with late-war radar spot, and all the other bells and whistles, about 1%. Is that a "reasonable chance"? That is for any kind of hit. Maybe on the citadel, maybe somewhere critical, maybe somewhere completely inconsequential. Of course, significant quantities of naval shells in reality fail to detonate as per specification or indeed at all even when they score a hit.

It has been suggested that is a "reasonable" tactic to exploit a perceived fire-control and ballistic advantage against an opponent not so well endowed, provided that the opponent agrees to "play nice" by observing by these "Marquess of Queensbury rules" and stay at the requisite extreme distance until defeated. Seems unlikely to me.

HMVS' earlier comment about bombing becoming more significant than long range shellfire with regard to provision of deck armour is -right on target :ok:

All the best

wadinga
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Re: Who won?

Post by Steve Crandell » Thu Jul 30, 2020 5:26 pm

Except that dive bombers at least, the bomb is travelling much slower than a 16" shell. And level bombers against a moving ship don't have much chance to get a hit, especially dropping only one very heavy bomb.

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wadinga
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Re: Who won?

Post by wadinga » Thu Jul 30, 2020 7:18 pm

Hi Steve,
And level bombers against a moving ship don't have much chance to get a hit, especially dropping only one very heavy bomb
Deck protection provision revolved around perceived threats, which don't always materialize. Bombing was perceived to be more accurate than it proved to be in combat, the precision of Mk 8 radar at 35km was unimaginable before the war.

As we seem to have established, the aircraft computer has to forecast the target position in 42 seconds time, whereas the ship 35 kms away has to forecast 75 seconds into the future. I think both had a pretty tough computational problem and it is thus that neither seem to have any hits.

The Germans "cheated" by putting radio control in a Fritz-X bomb and sinking the Roma and developing the Hs 293 which had a rocket engine as well for extra speed and penetration. Both were in service by 1943.

All the best

wadinga
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Bill Jurens
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Re: Who won?

Post by Bill Jurens » Thu Jul 30, 2020 11:40 pm

My thanks to Wadinga for his kind comments re INRO and Warship International.

Paul Mercer wrote:
"[Regarding the relative effects of a one ton bomb against a one ton shell, if I am correct in my understanding of the replies [to a previous question] the answer being that a shell would be falling at an angle but the bomb would be falling almost vertically and was more likely to penetrate the amoured deck. My question is this, presumably if a ship is firing at maximum range, the guns would be at maximum elevation and at a range of 30-35000 yards surely the shell would be falling almost vertically, like the bomb and therefore very likely to penetrate the deck armour."

It is rare for angles of fall of high-velocity naval guns to have angles of fall exceeding about 70 degrees, regardless of range. Depending upon exactly how one does the computations, at 35000 yards, the angle of fall of the US 16"/50 is about 44.3 degrees, and the striking velocity about 470 m/s, resulting an a resolved vertical component of about 66 mJ of energy. A typical half-ton bomb WWII bomb dropped from 15000 feet at an initial velocity of 250 knots would have an angle of fall of about 69 degrees and a striking velocity of about 280 m/s, resulting in a resolved vertical kinetic energy of about 15.8 mJ. For a one-ton bomb, the figures would be about 69 degrees (as before) but the striking velocity would increase to 288 m/s (not much difference) and the resolved vertical K.E. would go up to about 33 mJ, about half that of a 16" shell.

Other factors come in to play. Generally, more of the aircraft bomb is devoted to explosive load, so one should add in the effects of the explosive payload as well. On the other hand, the bomb is generally not nearly as robust as a gun-fired projectile structurally. So, the bomb might do quite a bit more damage if it did not penetrate, but would have a considerably lesser chance of penetrating in the first place unless the deck armor was somewhat on the thin side.

As is often the case, although it's relatively easy to assess these trade-offs on a case-by-case basis, it's usually much more difficult to generalize...


Mr. Mercer also wrote:

"While on the subject, I believe some of the Iowas were refurbished for the Vietnam and first Gulf wars with a considerable amount of dollars being spent on modernising the radar and fire control systems, so would that have enabled them to accurately fire at greater distances.(like 35000 yards) Does anyone have any information at what ranges they were firing at in those two wars?"

A lot was done to improve long range accuracy. Much of this revolved around better control of interior ballistic issues, as at long ranges the majority of dispersion can be traced to variations in initial velocity. I don't have any figures immediately at hand, i.e. at my elbow, as most of my data comes from target shoots, but my general impression is that in Vietnam and and in the Gulf most of the firing involved fairly long range firing against inland targets. Although I do have some insights into Gulf War shooting, I am not sure if any of it has since been declassified.

Bill Jurens

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