Total number of shells fired by Bismarck and straddles

[Antonio Bonomi]

Ciao all,

@ Karl,

according to my opinion it was Lindemann after having seen/received the torpedo alarm from Brinkmann to turn Bismarck hard out to starboard, he was in command of his ship engaged into a battle and an order to do so from Adm Lutjens was NOT necessary at all; he surely did not ask for that decison to be taken immediately.

In the opposite, while evidently into a disengagement action, he needed the authorization of Adm Lutjens to pursue PoW retreating, and he got a negative answer based on Adm Lutjens SKL received orders for Op. Rheinubung that prohibited him to engage on his initiative an enemy battleship unless a convoy was to be destroyed by doing that, and that was NOT the case.

Just like for Kpt Topp and Adm Ciliax on board Tirpitz during Op. Sportpalast, when the battleship is into the battle action, it is his commander to manage her based on received admiral orders on what to try to achieve.

@ all,

to better understand Bismarck firing methodology, you have to study the sequence they used to reach the "straddle " and than order the "rapid fire" like they did.

First the VOLLSALVE ( 2 semi salvoes of 4 guns each ) with large spread, than based on the observed results a GABEL GRUPPE 400 meters ( a group of 3 semi-salvoes with close spread, one short, one centered and one long intentionally ) than again based on the results observed : WIRKUNGSCHIESSEN ( rapid fire or fire for effect )..... that is when Schneider was heard to say : " GUT SCHNELL " ... which meant exactly that they had to start the rapid fire.

We covered this matter time ago and I produced a drawing to explain it :

viewtopic.php?f=1&t=1662&start=30

From what has been reported it seems that Schneider and Bismarck gunners went immediately on target on Hood and after the usual 2+3= 5 semi-salvoes described above the Bismarck rapid fire on target hit the Hood on the spotting top immediately and than with only other 4 semi-salvoes they obtained a fatal hit on the Hood magazines.

Based on the evidences we can state that when Schneider on Bismarck switched fire to PoW he did not reset the whole things restarting everything from the VOLLSALVE, as it was not needed ( while Jasper on Prinz Eugen did so switching fire at 05.59 ) but just continued to fire rapid fire with a minor correction factor and that is why he hit PoW "almost immediately" as reported by Capt Leach and PoW survivors.

Bye Antonio

[dunmunro]

Everyone tends to get mesmerized by Hood's destruction but the simple fact is that Bismarck probably only scored 5 hits during the engagement and 4 of these hits were scored outside the citadel zone, with one on Hood's fighting top, one on KGV's bridge and the UW hit, all being correct for line but over or under in range, in terms of hitting the citadel. Bismarck, in theory, had a functioning radar ranging system capable of generating very accurate ranges and range rates and yet she never landed a single round with the potential to enter PoW's citadel. The other factor is that the salvo that did destroy Hood was fired from only ~16.3k yds, substantially closer than most accounts state:
http://www.hmshood.com/history/denmarks ... encIVb.gif
since PoW scored a hit on Bismarck, just as Bismarck was firing the fatal salvo:
http://www.hmshood.com/history/denmarks ... encIVb.gif
and thus the range had to be within a few hundreds yds of the range indicated on PoW's track chart. These facts tend to support problems in Bismarck's 38cm elevation control system, IMHO.

[paulcadogan]

OK Duncan, I see your point. Schneider had the range "taped", yet landed only one hit that entered the target's citadel because of that elevation error over which he had no control.

The Prinz on the other hand scored a higher proportion of citadel type hits (2/2 on Hood, 3/4 on PoW), probably because the 20.3 cm gun didn't suffer from that problem?

But also, PoW was hit while executing her maneuver around the sinking Hood, making hard course alterations. This would obviously constantly affect the range rate until she settled on her 160 deg retreat course.

[frontkampfer]

But the one who scores the most telling hits first gains the upper hand - that's what counts in the end. And in the DS, that went to the Germans hands down, no dispute. They had the advantage from the start, based on the British approach, and they used it perfectly.

Paul,

I think your statement above says it all. In all the discussions I've read on this forum and in this thread in particular, your words sum up this battle. Everything else is secondary. As for the luck factor, someone once said "You make your own luck"!

Bravo-Zulu!

[dunmunro]

OK Duncan, I see your point.

Yes, that's what I'm trying to get at. Thanks for the info on PE's shooting.

[Thorsten Wahl]

Bismarck, in theory, had a functioning radar ranging system capable of generating very accurate ranges and range rates and yet she never landed a single round with the potential to enter PoW's citadel.
and thus the range had to be within a few hundreds yds of the range indicated on PoW's track chart. These facts tend to support problems in Bismarck's 38cm elevation control system, IMHO.

in general I was conform with your opinion that the Bismarck shooting wasnt that optimal. But ther are some specialties to be considered

In theory, the service regulations regarding accuracy let us expect roughly 30% hit probability at 15 km if target is straddled, -this was definately not the case.
The theory says roughly 1 hit out of a 4 gun Turmgruppe at 15 km if target is straddled.
But Bismarck was shooting at two different targets.

The observed salvo spread was found to be remarkable small. this indicates no abnormal dispersion.

Most of the hits were in upper structure, so these salvos could be over. maybe assessment of salvo impact was faulty.
Even if there was a problem with the elevation, the result(overshooting) was a systematic error similar to an increased muzzle velocity, permanent tailwind or reduced air density.
This should result in a manual correction of the firecontrol equipment to decrease elevation.

By comparision of the real results to expected results according service regulations the achieved hit probability was comparable to other shootings.
In this regard the shooting was not conspicuous

For a detailed analysis you need the shooting documents from the bottom of the atlantic.

hits on POW
in between 06.01min,00sec and 06.03min,00 sec POW made a roughly 135 deg turn
so ~10 degrees per 10 seconds
the bismarck shell trajectorys from this drawing
http://www.hmshood.com/history/denmarks ... damage.gif
were conform to 20-30 seconds intervals between the 3 hits but i dont know the exact sequence of the hits.
3 hits on probably 3 succeeding salvos at a turning ship is a extremly favorable result. This requires a predictive change of the fire solution to be constantly on target.

[José M. Rico]

Even if there was a problem with the elevation, the result(overshooting) was a systematic error similar to an increased muzzle velocity, permanent tailwind or reduced air density.
This should result in a manual correction of the firecontrol equipment to decrease elevation.

When I was a boy I had an air rifle with a defect in the barrel so the pellets always missed the target no matter how well I aimed. Therefore to correct this deffect, I began aiming a little to left of the target in order to get hits.

[dunmunro]

My reading of the AVKS report is that the elevation error was more or less random, and so it couldn't be corrected for. Basically, after a salvo is fired, the guns are automatically lowered to the loading positions, the guns are loaded and then return to the firing elevation as requested by the FC computer. However, it appears that the guns would not go to the requested elevation, but to elevations that were +/- ~15 minutes of the requested elevation:

c. Calibration [adjustment] characteristics
During the eight ­week period that the AVKS was onboard, the calibrations of the elevation
remote control had changed repeatedly, although the remote control had never been worked
on. The reason for this [drift of calibration] could not be established with certainty. The drift in
the calibration settings requires a continuous recalibration. Since the calibration work is very
difficult and time­ consuming, and since it cannot be readily performed by insufficiently trained
mechanic personnel, this means that there will be a persistent uncertainty factor of this
equipment for the time being.
d. Accuracy
Because of the lack of sufficient sea motion, the accuracy of the elevation remote control during
sailing, the elevation control mechanism could only be determined with a sinusoidal
oscilloscope. The oscillograms revealed a control error average misalignment of 7/16 degrees,
but this also included several series of measurements of larger deviations of 9.6/16 degrees.
The control error of the elevation remote control was independent of whether the control
sequence was just based on the elevation value indicator -- barrel alone, or the entire remote
control chain of commands that was sent via alignment ­elevation indicator, target indicator,
alignment­ elevation indicator to the turret.
The number of larger errors, which occurred during several measurement series, can obviously
be traced to very marked control­ technical deficiencies, as for example, in the imprecise
workings of both delayed­ action increments [step­ups?] (more about this in the special report);
moreover, the accuracy of the remote control of the 38 cm turret is completely inferior to
the 28 cm and 20.3 cm turrets. In this, the substantially larger intrinsic dynamic forces of the
38 cm guns play a considerable role. A further reason is evident for this mechanical slack
[looseness] is given in cipher 9.

Obviously, I can't prove this was a factor in Bismarck's shooting, but Bismarck and PE did seem to have a very different pattern to their hits.

[frontkampfer]

When I was a boy I had an air rifle with a defect in the barrel so the pellets always missed the target no matter how well I aimed. Therefore to correct this deffect, I began aiming a little to left of the target in order to get hits.

Jose,

Good Point! In early American history that kind of shooting was called that "Kentucky Windage".

[paulcadogan]

Ok but what about Bismarck's other engagements?

vs. Norfolk, May 23: 5 salvoes fired, A & B turrets only, straddles obtained (not sure how many), splinters hit the cruiser, no direct hits, one shell was seen to ricochet off the sea 50 yards away (Kennedy, Pursuit)

vs. Suffolk, May 24 pm, during release of the Prinz; First salvo 1000 yards short, later ones "near enough to loosen rivets in the plating aft". No hits.

vs. Sheffield, May 26 pm - 6 salvoes fired, first was over 1 mile short, second was a straddle with splinters raking the ship, killing three and wounding 9. Other four fell close as Sheffield retreated. No direct hits.

vs. Rodney, May 27 - 3rd salvo straddled with splinters going aboard. This apparently was the closest she got. No direct hits.

vs. KGV, May 27, (the Baron in the aft director, aft turrets only) - 4 salvoes, 4th straddled "3 (shells) over, 1 short". No hits.

[dunmunro]

Ok but what about Bismarck's other engagements?

So ~5 straddles and no hits...statistically improbable, but consistent with the AVKS report.

[José M. Rico]

When I was a boy I had an air rifle with a defect in the barrel so the pellets always missed the target no matter how well I aimed. Therefore to correct this deffect, I began aiming a little to left of the target in order to get hits.

Jose,

Good Point! In early American history that kind of shooting was called that "Kentucky Windage".

I didn't know that. Thanks for the history lesson!

[Dave Saxton]

If Bismarck's RPC was still giving trouble they could switch to the alternative shooting procedures. Bismarck was quickly and consistently straddling, so this doesn't seem to indicate a troublesome intractable technical problem, and PG had basically the same FC systems and procedures. What this does indicate is that actual combat shooting sometimes does not produce the same results as the theoretical probabilities. As Jose pointed out the measure of good shooting is straddling and there is no certainty of hits from straddles -only a probability. For a probability to work out there must be a large enough sample, as in several straddling salvoes grouped together. The Bismarck is firing strings of only a few straddling salvoes; before switching targets, ceasing fire, having its own FC stations disabled, or otherwise having the string of straddling salvoes interupted.

[lwd]

In regards to the probability of hitting at various ranges it might be worth taking another look at the chart at:
http://www.navweaps.com/Weapons/WNUS_16-50_mk7.htm
While this is for a US weapon and so not directly comparable it should be "ballpark" for others as well. Here are some of the relevant pieces:

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
10,000 yards (9,144 m)___32.7____________________________________22.3
20,000 yards (18,288 m)__10.5____________________________________4.1

Note that Bismarck's shooting falls in pretty close as based on the above I would expect her to have a P(H) vs Hood of between 3 and 5-5%. Somewhat lower than the above table as Hood was following an oblique course. The fact that she was in the upper side of this especially if there was an elevation problem as suggested indicates she was shooting pretty good although the number of rounds and the conditions make it hard to make any strong statistical statements in that regard.

As to the effect of luck I think it is clearly indicated. If the P(H) for a single round is say 10% then if you fire a 4 gun salvo the chance of getting one or more hits is ~45%. Obviously one doesn't hit if one doesnt stradle however stradles don't guarantee hits. The more often one straddles and the closer the target is to the center of impact the higher the probability of hits. Given a straddle especially one near the center of impact tight patterns also increase the probability of hits. Howver even if the P(H) were to go up to 50% given a successful stradle there is still a bit over a 6% chance that all shells will miss. So luck is clearly a factor in both the hit and even more so in the hit location. Skill and good equiment can increase both the probability of straddles and the probability of a hit given a stradle but it's not deterministic. Catostrophic hits are also very much a matter of luck. Certainly other ships had a chance of being destroyed by such hits and weren't. For instance both Kirishima and Yamashiro took quite a few hits that had the potential of causeing a catastrophic destruction but didn't. Like wise Hood could have been hit in quite a few locations that would not have resulted in catastrophic destruction. Some may have cause serious degredations in her fighting ability others minimal degradations. It is however pretty clear that if both British capital ships stay in the action Bismarck is very likely to take enough damage that her chances of survival are very poor and Eugen may as well.

[dunmunro]

. Obviously one doesn't hit if one doesnt stradle ...

A hit can occur, especially with a flat trajectory gun, where the salvo would not straddle the target and this may have occurred in several instances, especially the 38cm hit on Hood's fighting top and PoW's bridge.