Total number of shells fired by Bismarck and straddles

[lwd]

. 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.

Good point. Frankly if the extreme round on either end hits is it still considered a straddle? For instance if the underwater hit on POW had been the longest round would that have been considered a straddle? Certainly the Germans wouldn't have recorded it as such as all the splashes would have been short.

[tommy303]

The most probable reason for the differing shooting patterns between the Bismarck and Prinz Eugen may have had more to do with the differing GM between the two ships. Bismarck had a very great GM compared to the cruiser, giving her much greater stability, but the stability came at a price--the roll period was very short and angular acceleration much higher than in Prinz Eugen, making it harder for the RPC to the guns to keep them on target. If the fire control crew on Bismarck was using rapid fire proceedures, i.e., the director layer firing on the up roll instead of using the gyro-stabilized firing circuit in the fire control center, rapid roll might have caused the shells to leave the muzzles just very slightly late, bearing in mind there is a finite time between closing the firing circuit and the instant the shells leave the muzzles. In Prinz Eugen, the roll period was a bit longer and slower, which must have made it easier for the fire control teams.

[Thorsten Wahl]

the director layer firing on the up roll instead of using the gyro-stabilized firing circuit in the fire control center, rapid roll might have caused the shells to leave the muzzles just very slightly late, bearing in mind there is a finite time between closing the firing circuit and the instant the shells leave the muzzles

this is not quit right
from here
viewtopic.php?f=1&t=1145&p=34581&hilit= ... ure#p34581

2)
ancillary procedure
aiming with follow pointer method with central firing and/or Zentralvorzündwerk for roll and pitch

the Zentralvorzündwerk was a correcting unit for movement of the barrel due to roll and pitch, so even the primary RPC was not functioning, the Vorzündwerk was also able to correct ignition timing of propellant charge up to the required time the shell leaves the muzzle to ensures the correct orientation of the barrel on firing.

im not sure, but I hope my words are clear

[tommy303]

im not sure, but I hope my words are clear

Your words are always concise and easily understood. Thank you.

[Djoser]

Really, as far as 'luck' goes, I think it was fairly evenly divided.

What with Hood blowing up from a magazine detonation; but then Bismarck getting hit in the rudder when he was that close to reaching safety despite the entire Royal Navy hounding after his ass, Bismarck getting all 4 main battery guns in both forward turrets knocked out with one hit, the nearly simultaneous destruction of the primary fire control position, and so forth.

I am not so sure how unlikely it was that Hood would blow up given a hit anywhere near the magazines, major and minor; given the propensity of the British BCs to do so. Even with the stacking of opened charges being a likely cause for 1-2 of the fatal explosions at Jutland, we have the case of the Queen Mary which quite likely went the same way Hood did, from the detonation of the 4" magazines setting off the big one--in her case the forward rather than the rear. We cannot know for sure in either case, but with 4 out of the 12-13 British BCs blowing up all told (not counting the Furious, et al, as BCs), there was clearly a weakness and it cannot all be laid on some overeager gun crews in one battle.

The British BCs were vulnerable, and the Hood was going up against the best adversary in the world at that time. Not that she was destined to blow, but I would have rather quickly chosen the POW as my ship to be a crew member of, hands down, were I to have a choice.

Only a damned fool commanding any sort of major military force (or minor come to think of it) would fail to account for the improbable going wrong just when he needed 'good luck', or 'fair odds' on his side.

Bismarck's gunnery was clearly not deficient, not as far as I can tell--and a whole lot of gunnery experts would appear to agree. The Swordfish pilots were clearly not incompetent (and were clearly as heroic as anyone in the campaign when it comes down to it).

[Dave Saxton]

What were the relative wind and sea conditions for each warship involved?

[paulcadogan]

The wind was 7 - 10 knots (Force 3) from the east and the sea conditions "3" according to PE's KTB. According to the Beaufort scale, the sea would be 0.6 - 1 m with large wavelets and scattered whitecaps. This is consistent with the film footage, I think.

For the British, much spray was being produced at the bows which was fogging the RF's of the forward turrets which could not, as a result, produce any range readings.The Germans reported no such problems as the prevailing wind would blow any spray away from their line of fire.

PoW's 15 ft. RF on her DCT did not give a satisfactory range either and her gunnery radar was not running at the opening of fire. Her GO used other methods to get a range estimate which turned out to be 1500 yards too great followed by down ladders til he straddled and hit on the 6th. Hood probably had radar ranges given the fact that her conning tower director and its 30 ft. RF would also have been spray-affected (she had no optical RF on the spotting top director) and her two opening salvoes were pretty good for range but out for line. (This also explains why her gunnery degraded after the spotting top was hit, knocking out her radar.)

[RF]

. Hood probably had radar ranges given the fact that her conning tower director and its 30 ft. RF would also have been spray-affected (she had no optical RF on the spotting top director) and her two opening salvoes were pretty good for range but out for line. (This also explains why her gunnery degraded after the spotting top was hit, knocking out her radar.)

This would not also be influenced by firing at the wrong (smaller and shorter in length) target would it?

[paulcadogan]

This would not also be influenced by firing at the wrong (smaller and shorter in length) target would it?

Good question. I've often wondered if Bismarck had been where PE was, if Hood's 4th salvo which barely missed the latter, might not have hit Bismarck.

But looking at Hood's early fall of shot, you can see how Moultrie was working: shoot, spot, correct, shoot..- it all made sense:

Salvo 1: Left 150+ m ....correction right for line
Salvo 2: Left 100+ m ....correction right for line
Salvo 3: 1 shell left 50 m, one shell short (50 m)...correction slightly right for line, up 400
Salvo 4: Over, in line (photo - these shells must have just skimmed over the Prinz amidships aft to land where they did)

What happened next is the mystery. It should have been "Down 200...Shoot"....goodbye Prinz Eugen, but instead, Jasper says he was told "quite a few impacts" landed in the wake.

Why would Hood lose line then? The only reason I can think of is that at that point the first 20 deg. turn to port started, changing the rate calculations which her Dreyer FC table was hard pressed to manage. So her 5th salvo was correct for range, but fell right for line.

Then she took the boat deck hit, quickly folowed by the spotting top hit, with Captain Kerr trying to contact the spotting top to order Moultrie (most likely up there in the director) to shift target right (?)and failing to get through. (Briggs)

There is a delay until second GO in the conning tower director realizes there's nothing further from Moultie and takes over. (PoW observes Hood blazing and not firing and notes "Hood out of action" on her plot). The second GO has not received the communication from the bridge (why?), he cannot see Bismarck to the right belching the larger gun flashes to know he's on the wrong target - he can only see one enemy ship at a time. He is having trouble with spray-fogged lenses. He does his best firing the sixth salvo at approximately the same point as the 5th to start over. It falls right again, in PE's wake.

He's getting no spotting info from aloft, his A-Arcs are now open, but with flames from the boat deck licking over the roof of X-turret, the aft guns hold their fire. The forward guns fire three more salvoes, but spotting is difficult due to spray from the bows and shell splashes. The shells continue to fall aft of Prinz Eugen as Hood's wheel is put over to port to begin the second turn. As the boat deck fire dies down, Y-turret joins in...A, B and Y fire together as Bismarck's 5th salvo falls.......

The greatest mystery is why the orders for shift of target did not seem to get through to the gunners.

So I estimate Hood fired 10 salvoes (Antonio's estimate too, but also the number quoted in PE's KTB) totalling 21 shells, no straddles per se, but her 3rd and 4th bracketed the target.

Plausible?

Paul

[Djoser]

Nicely written, Paul...

[delcyros]

Some rangeplot´s I did based on primary source material and Antonio Bonomi´s paper on DS. First for PRINCE OF WALES engaging BISMARCK.
A few observations I made:



[A] note the large initial error in range
note how PoW stepped down the range in bracket pairs, requiring the fore turrets to alternatively fire 2 & 4 gun salvos and later 2 & 3 gun salvos. This was faciliated by a higher rate of fire than BISMARCK
[C]note that the three hits on BISMARCK mark a perfect line at a very constant change rate (-800 yard/min)
[D]note that BISMARCK didn´t changed course n between the three hits, thus the appearent constant change rate is a true one
[E]note that there is likely a fourth straddle which went unnoticed in between hit No. 2 & 3. This may be in part attributable by the few splashes which may have obscured that the MPI was set right on target (in within the dispersion pattern these may have been short or wide).
[F]note that two more salvos were spotted either wrong (short while beeing long and vice versa) or may have straddled with the splashes behind target not beeing noticed.

That makes for 4 probable straddles (+2 more possible) and three his resulting from them.

A similar rangeplot exists for BISMARCK

[RF]

Could you post it for comparison?

[dunmunro]

Some rangeplot´s I did based on primary source material and Antonio Bonomi´s paper on DS. First for PRINCE OF WALES engaging BISMARCK.
A few observations I made:



[A] note the large initial error in range
note how PoW stepped down the range in bracket pairs, requiring the fore turrets to alternatively fire 2 & 4 gun salvos and later 2 & 3 gun salvos. This was faciliated by a higher rate of fire than BISMARCK
[C]note that the three hits on BISMARCK mark a perfect line at a very constant change rate (-800 yard/min)
[D]note that BISMARCK didn´t changed course n between the three hits, thus the appearent constant change rate is a true one
[E]note that there is likely a fourth straddle which went unnoticed in between hit No. 2 & 3. This may be in part attributable by the few splashes which may have obscured that the MPI was set right on target (in within the dispersion pattern these may have been short or wide).
[F]note that two more salvos were spotted either wrong (short while beeing long and vice versa) or may have straddled with the splashes behind target not beeing noticed.

That makes for 4 probable straddles (+2 more possible) and three his resulting from them.

A similar rangeplot exists for BISMARCK

Here's PoW's salvo chart:

and your chart doesn't seem to correspond to the above, since you have the first straddle on salvo 7, not 6 as per PoW's chart, which indicates straddles on salvos 6, 9 and 13. I don't know if you have seen this, but I worked out the exact number of rounds fire per salvo based upon PoW's gunnery report and you can read that here:
http://www.hmshood.org.uk/forum/phpBB3/ ... 0abbd7256a

[delcyros]

Hi D.,

PoW's gunnery records is the primary source I based my graph on. My first straddle occurs with hit no.6, not with no.7, which was observed to be over. Thus the sequence No6, No.9 and No. 13 is the correct one for both. Where do You read that hit No.7 is the first one in my drawing? You must be mistaken.
I found Your datas highly interesting with regards to fired vs ordered and I didn't noticed that before, thanks for the pointer.

[dunmunro]

You have the first hit plotted at about 19400 yds, when the range on PoW's salvo chart is 21150 yds. I assumed that the first hit you plotted must have come from salvo 7, fired at 19825 yds. How do you account for the large variation in range between your chart and PoW's, for salvo 6?