USS South Dakota at Guadalcanal

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Steve Crandell
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Re: USS South Dakota at Guadalcanal

Post by Steve Crandell » Mon Feb 24, 2014 7:42 pm

Dave Saxton wrote:Another interesting thing about the action report is the level of training reported for Washington's gunnery crews. Only one night gunnery drill had ever been conducted and that was 10 months previous. The last time any gunnery drill had been conducted was 6 months previous.
Fortunately battle practice was apparently more common as the war progressed. From the Fischer/Jurens study:

"The U.S. Navy's fast battleships appear to have had the luxury of more main battery practices than their contemporaries. Alabama, for instance, fired five main battery battle practices between April and September 1943 alone, a rate eight times greater than Yamato, which fired only eight main battery practices in fourty months."

The fast battleships were rushed into service early in the war, and undoubtedly this resulted in less experienced gunnery departments.

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Re: USS South Dakota at Guadalcanal

Post by Dave Saxton » Tue Feb 25, 2014 1:24 am

Kind of disproves the idea that the crews need to be well worked up to perform well.
Entering a night sea battle is an awesome business.The enveloping darkness, hiding the enemy's.. seems a living thing, malignant and oppressive.Swishing water at the bow and stern mark an inexorable advance toward an unknown destiny.

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Re: USS South Dakota at Guadalcanal

Post by RNfanDan » Tue Feb 25, 2014 2:45 am

Dave Saxton wrote:Kind of disproves the idea that the crews need to be well worked up to perform well.

I might not go quite that far, Dave...disproval requires proof of at least equal strength and veracity. There is a possible suggestion to that end, but the sheer number of actual firings has little to do with working up a crew. Training teams to perform well could be achieved without actually firing the weapons---just as real flooding or fires on board a ship were not required to work-up efficient damage-control procedures.
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Re: USS South Dakota at Guadalcanal

Post by Byron Angel » Tue Feb 25, 2014 4:24 am

alecsandros wrote:
Steve Crandell wrote:
alecsandros wrote:The important mention to make is that we do not know the spgpm figure of the night firings. Most likely it was higher than the one achieved by the USS Washington in the real battle.
Why? In training they often fire more slowly than in actual combat.
Concentration firing meant all ships were firing at maximum possible rof, with each ship output, spmpg and hpmpg being measured and compared to her consorts. Nominal rof for the triple turrets of 16" was 2 spmpg. Washington delivered 1.35 spmpg.

In trials conditions, the " average ' for continous rapid firing was 2,5 spmpg ( averagr for all the heavy guns of the ship ), at close range.

Note that the 22 hits claim is above average trial results and also implies each 3-gun salvo had 1 hit which is pretty difficult for Washingtoms spotters to fail to observe ( especialy as the kirishima was illuminated eith starshell)

Alecsandros,

..... On what reference/source to you cite the nominal 16in rate of fire as 2 spgpm? It is not consistent with official USN documentation I have seen, where a value of 1.5 is given at 10,000 yards is the highest value stipulated, with spgpm rapidly falling to 1.0 for ranges =/> 15,000 yds. Backward extrapolation of the graph curve for ranges < 10,000 yds <<<suggests>>> that a rate of 2.0 MIGHT be possible, but I have never seen such a value actually stated for any range. I hope you are not conflating the maximum mechanical rate of fire of the gun for its average rate of fire.

..... On what basis do you claim that AP hits were easy to observe? Every source I have ever read, going back to WW1, without exception has emphasized the difficulty in detecting heavy caliber AP hits upon armored ships at any distance over about 5-6,000 yards <<< in daylight >>>, which is (probably not coincidentally) about the maximum distance in daylight over which the flight of a heavy caliber projectile can be followed by visual means. See the chapter on the Bismarck action contained in Progress in Naval Gunnery - 1942" for further corroboration on this point. If hits were so easy to see, one is forced to ask why Washington's action report made zero claim as to total number of hits made and only specifically mentioned those very few (2 or 3) hits that produced obvious (most likely secondary) explosions aboard Kirishima.

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Re: USS South Dakota at Guadalcanal

Post by alecsandros » Tue Feb 25, 2014 6:28 am

"The objects of SRBP [Short range battle practice] were to test and train gun pointer groups at pointer fire, to test and train loading crews at maximum safe rates of fire to test material, and to stimulate interest in gunnery. It certainly succeeded in increasing speed. In 1919 battleship main batteries averaged about 1.9 Shots Per Gun Per Minute [SPGPM]. By 1930 the average rate had risen to about 2.5 SPGPM, though for a variety of reasons it never got much higher than this. In fact, the obsession with speed in Short Range Battle Practice finally became so great that in 1938, CNO, fearing that some ships were not checking for bore clear with sufficient care, promulgated regulations specifying a minimum twenty-four second loading interval, and imposing a penalty if it was not upheld.34 Navy "E"s in gunnery, predominantly displayed on the sides of turrets between the wars, were primarily awarded for performance in Short Range Battle Practice. Aside from being a fertile source for the study of loading accidents, the results of SRBP are of relatively little historical value, and will not be studied here."


===

Were did I say spotting APC hits was easy ? I said they were spotting the water columns ! At the same time, Kirishima was illuminated with starshells from 4x5"/L38, which fired 62 shells against her. So it was rather easy to observe the fall of shot.

===

More into the early war 16"/L45 problems:
"The introduction of the new 16"/45 and the 16"/50 batteries installed in the treaty battleships in the late 1930s and early 1940s was somewhat less than agreeable. New 16-inch range tables used incorrect powder temperature velocity differentials and inaccurate instructions to compensate for the rotation of the earth. Charge assessment problems gave the new 16"/50s an initial velocity about 30 ft/sec higher than expected, so they initially overshot their range tables, especially when the range was long. At the same time, proving ground experiments showed the 'jump" for the new guns to be negative, rather than positive, meaning they undershot their range tables when the range was short. The unfortunate combination caused a vexing problem which took at least two years to solve. Further, although the new 14-inch guns were lighter and more reliable than their predecessors, when equipped with similar fire control systems they proved to be no more accurate than the guns they replaced.26 "

"26 In fairness, the overshooting-undershooting problem would have only been a problem in true blind fire, where no observation of the fall of shot was possible; in most practical cases, of course, the initial salvos could be brought closer to the target by imposing ACTH (Arbitrary Correction To Hit) and successive patterns could be spotted on to a target visually or by radar. Inherent dispersions, of course, couldn't be corrected that way. The Bureau of Ordnance expected the nine-gun patterns given by the 16-inch batteries mounted aboard the Washingtons, South Dakotas and Iowas to be slightly larger than the eight-gun pattern sizes for the old 16-inch guns mounted aboard Colorado, Maryland and West Virginia. Specifically, eight old guns were expected to yield an average range pattern of 1.8% of range while nine new guns would give a 1.9% pattern. These were ideal figures; in practice the old 16-inch guns gave a seven-gun pattern size of about 2.2% of range during their last firings in 1941. The dispersion of the 16"/45 and 16"/50 guns, incidentally, was essentially identical; ranging sheets at Dahlgren often listed dispersions for the two types interchangeably. Today, the 16"/50 yields a 9-gun pattern size of about 1.5% of range at short ranges, slightly less if the range is long. Viz. Bulletin of Ordnance Information, No.3, 1945, FTP 2101, Reports on Gunnery Exercises 1940-41 and Naval Weapons Laboratory Tech. Report No. K-26167. "

Target practice:

"As before, the normal battle target has been replaced by the outline of a 785 foot, 20 knot target. The signal to shift targets came at 1 minute 55 seconds into the firing, but fire was not shifted until after the fourth salvo..."

Dipsersions at 13000 yards:
Note the NUMBER of shells fired in order to obtain several hits.
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Re: USS South Dakota at Guadalcanal

Post by pgollin » Tue Feb 25, 2014 10:15 am

.

A couple of points ;

1: In assessing rate of fire one must either ignore the first round or else assess the time from first loading or through to last re-load (unfired). If one uses the first round you initially get a rate of fire of infinity for the first salvo.

2: As pointed out elsewhere the USN ignored what they regarded as "gross errors" in their practice shoots, which skewed their results.

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Re: USS South Dakota at Guadalcanal

Post by Byron Angel » Tue Feb 25, 2014 12:53 pm

Short Range Battle Practice explains the 2.5 spgpm RoF value cited and corresponds to the previously mentioned reverse extrapolation of the graph curve and does in fact approach the mechanical rate of fire of the gun. According to gunnery doctrine documents (1939, 1944, 1945, 1946), the higher RoF was a function of Continuous Fire mode whereby the director time interval was ignored. While spgpm went up in Continuous Fire mode, accuracy went down according to these documents. Washington was firing in what was described in the a/m documents as Rapid Fire - where the main battery remained under director control and the firing key pressed as soon as one or more turret ready lights were lit. Hence the trade-off was reduced rate of fire in exchange for improved accuracy of fire. Average (i.e. - nominal) BB main battery rate of fire, according to USN gunnery documents of the era ranged between 1.5 rpm at 10k yards to 1.0 rpm beyond.

---

The inference to be drawn from your post ( "also implies each 3-gun salvo had 1 hit which is pretty difficult for Washington's spotters to fail to observe" ) was that hits could have been inferred by subtracting splashes from shots fired in the salvo. Doing so (IMO) is more difficult than this suggests. Also, IIRC, Washington's action report mentioned that the starshell illumination was not of that much use in support of spotting against Kirishima. No time now to track down the exact reference - maybe tonight.

---

Yes, the 785 target = constructive target.


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Re: USS South Dakota at Guadalcanal

Post by alecsandros » Tue Feb 25, 2014 1:17 pm

In all fairness, dispersion patterns also certainly improved between 1931 and 1942, but I do not know by what factor.

However, the design of USN battleship triple turrets specified a rate of fire of 2 rounds/minute/gun, which I can not understand why would not be attained ?

(Even the old HMS Rodney obtained 3 rounds/minute average in the early segments of Bismarck's last stand (and she also fired from triple 16" turrets))

I am thinking that the battle between Kirishima and Washington was a very short battle, so the gunners were not (to) fatigued... Rate of fire was usualy higher in the opening phases of the battle, and gradualy fell due to fatigue in the mid and late parts. See USS Idaho's "fire to exhaustion" combat practice of Oct 1942...

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Re: USS South Dakota at Guadalcanal

Post by alecsandros » Tue Feb 25, 2014 2:26 pm

I am thinking that the 1.3 spmpg obtained by USS Washington shows a rather deliberate firing, with long intervals for observations of fall of shot and corrections.

This is because:
1) I believe the triple 16" turrets were capable of higher sustained rate of fire , at least for short battles
2) the time of flight of a 16" shell at 10.000y is no more than 15 seconds. Considering 1.5 rpmpg ordered, this means one shot at every 40 seconds or so.

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Re: USS South Dakota at Guadalcanal

Post by Steve Crandell » Tue Feb 25, 2014 3:15 pm

alecsandros wrote:I am thinking that the 1.3 spmpg obtained by USS Washington shows a rather deliberate firing, with long intervals for observations of fall of shot and corrections.

This is because:
1) I believe the triple 16" turrets were capable of higher sustained rate of fire , at least for short battles
2) the time of flight of a 16" shell at 10.000y is no more than 15 seconds. Considering 1.5 rpmpg ordered, this means one shot at every 40 seconds or so.
They were firing on turret ready light. This means that as soon as a turret indicated it was ready to fire, it was fired from Main Fire Control. This would be about as fast as reasonably possible, and not waiting for fall of shot at all.

In actual combat sometimes you have delays for various reasons, and sometimes the turret officer would turn on the ready light with one or more guns not ready to fire due to various reasons. On the combat film of Bismarck firing at DS there was at least one salvo from a 4 gun group only 25 seconds after the previous one from that group, but she averaged only about one rpgpm for the engagement. At Surigao Strait West Virginia recorded her second radar spot of a full 8 gun salvo 35 seconds after the first one, and that is faster than the theoretical maximum rate of fire for her older 16" main battery. However, she also fired a couple of salvos with only 5 or 6 guns, and after the first 5 salvos most of them were only 7 guns. That sort of thing happened a lot and would reduce the average spm per gun.

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Re: USS South Dakota at Guadalcanal

Post by alecsandros » Tue Feb 25, 2014 3:27 pm

... I know what the report says. Still firing 1 shot every 40 seconds seems rather slow. As you can see above, averages of 24 seconds were normal for US BBs.

Bismarck only ordered rapid firing after salvo 4. This is why the average rof seems so low. In fact, accoring to Bismarcks artillery report of march 1941, 38cm shells were delivered to the main turrets at a rate of 23-25 shells/minute ( total for all guns, suggesting a ratr of fire of 2.9 -3.1 spmpg )

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Re: USS South Dakota at Guadalcanal

Post by Dave Saxton » Tue Feb 25, 2014 3:29 pm

RNfanDan wrote:I might not go quite that far, Dave...disproval requires proof of at least equal strength and veracity. There is a possible suggestion to that end, but the sheer number of actual firings has little to do with working up a crew. Training teams to perform well could be achieved without actually firing the weapons---just as real flooding or fires on board a ship were not required to work-up efficient damage-control procedures.
Hi Dan,
Yes disproved might be too strong of a word. Nonetheless, I don't think anybody would argue that Washington's crew did not perform relatively well despite the lack of practice shoots. Indeed South Dakota's crew had more actual combat experience. The point being that the number of practice shoots may not be a reliable barometer of probable shooting performance in combat.

The realitively good gunnery performances of German ships and British ships may argue against the above point, however, because the German ships, contrary to common knowlege, were kept fairly well drilled. It was noted about how much fuel Tirpitz was using in routine battle practice shoots throughout her time in Norway, for example. Scharnhorst conducted a whole series of night battle practices with live fire shoots in the weeks leading up to North Cape. The fjords allowed the German front line warships to continue routine battle practice in relative safety during war time. I have copies of records of KGV class practice shoots made during the war, so I know they were drilled.
Entering a night sea battle is an awesome business.The enveloping darkness, hiding the enemy's.. seems a living thing, malignant and oppressive.Swishing water at the bow and stern mark an inexorable advance toward an unknown destiny.

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Force Battle Practice 1930 - 1931 FoS Chart

Post by Byron Angel » Wed Feb 26, 2014 11:43 am

The above graphical fall of shot chart represents fall of shot of multiple salvos fired without radar fire control. Hence, ranging and spotting errors of the salvos themselves almost certainly would presumably have accounted for the great majority of the apparent dispersion. It is not possible to determine actual individual salvo pattern dispersion from this.

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Re: USS South Dakota at Guadalcanal

Post by alecsandros » Wed Feb 26, 2014 11:57 am

... That was not my intention,
but to see just how many shots were needed for obtaining a certain number of hits on a battleship target.

I would expect improvements though between 1931 and 1942...

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Re: USS South Dakota at Guadalcanal

Post by Byron Angel » Wed Feb 26, 2014 12:36 pm

alecsandros wrote:... I know what the report says. Still firing 1 shot every 40 seconds seems rather slow. As you can see above, averages of 24 seconds were normal for US BBs.

Bismarck only ordered rapid firing after salvo 4. This is why the average rof seems so low. In fact, accoring to Bismarcks artillery report of march 1941, 38cm shells were delivered to the main turrets at a rate of 23-25 shells/minute ( total for all guns, suggesting a ratr of fire of 2.9 -3.1 spmpg )

..... FWIW, 16in/45 (2700 lbs) time of flight at 8500 yards range was about 12 seconds. Salvo interval was about 13.3 seconds during the first phase of Washington's fire. The POSSIBLE implication is that fire was purposefully withheld until fall of shot of the preceding salvo had been observed (by no means uncommon). The one or two second interval thereafter would likely be accounted for by the need to wait for the ship's motion to achieve a proper vertical position. The firing key was controlled by Director IV, which was also the director tasked with keeping continuous level and cross-level.

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