Bismarck and her contemporaries

[Dave Saxton]

No need for correction Francis, your points are well taken.

[dunmunro]

Lutscha is right on these points. TP in March 1942 had most of these short comings, with the exception of the single shot 37mms, at least partially addressed and turned in a much better performance. In this case the British were able to approach almost to with in torpedo release range hidden by cloud before TP could open fire as well-negating TPs heavy flak batteries for the most part. The big difference was the greatly increased volume of fire from light flak, more accurately aimed, made possible by the addition of 20mm Vierling mounts. The Vierling was an effective AA weapon capable of lethal accuracy. Don't let the caliber fool you, because this high velocity weapon had the effective reach of most 40mm weapons.

For the Allies the most important AA weapon upgrade was the 40mm Bofers. McMullen's post action report after the loss of Prince of Wales paints a picture that supports the importance of light , high volume of fire, weapons. The heavy flak and the slow firing pom poms both in director control proved completely ineffective during the sinking of Prince of Wales. McMullen points out that the 40mm Bofers and the 20mm Oerlikons with tracer were at least some what effective. This same Air Group was cut to pieces in the Solomons in 1942 by American transport ships equipped with Bofers.* Allied ships would find the Bofers in large numbers indespensable as the war progressed

Prinz Eugen had its 37mm battery replaced with 40mm Bofers and this improved PG's AA capability.

The 37mm weapons were upgraded to automatic fire like the land versions in some cases. I have one refrence that this ocurred on TP but have not been able to confirm this.


* American light flak had the advantage of the excellent MK14 computing optical gun sight designed by Stark Draper of MIT

McMullen's post action report is a bit misleading, as PoW's pom-poms did record hits on IJN aircraft, where the 40mm bofors didn't. Mcmullen noted that IJN aircrew were likely to take avoiding action when faced with tracer fire, but he doesn't actually note any 40mm hits. Of the 4 aircraft shot down by Force Z, pom-pom fire got at least two, and probably all 3 that crashed immediately, and possible the the 4th that crashed en-route to its base. Repulse's pom-poms got 2 of the aircraft, IIRC. The pom-poms biggest problem was defective ammo which greatly cut the effective RoF, and secondarily the lack of radar ranging for the Mk 4 pom-pom directors which had gyro lead computing sights.

The Pom-pom, with it's very large on mount magazines theoretically had a higher effective RoF than the Bofors despite a slightly lower maximum RoF.

[alecsandros]

Duncan,
I read that 4-5 of the attacking planes crash-landed on return, because of heavy damage suffered. They were not repairable.
Do you have any more info on this ?

[dunmunro]

Saturation alone doesn't do it either. This was the problem with barrage fire. For example, after 12 salvoes in directed fire producing no results, and now with the rate change to quick to keep up to, PoW's 5.25's switched over to barrage fire which made it less likely that damage would be inflicted. It would be pure luck that aircraft would fly through the barrage's kill zone at exactly the right moment in time. A British operational researcher described barrage fire as: " based on sloppy thinking and bad arithmetic"

PoW's 5.25s didn't shoot down any bombers, but they did damage 5 of 8 in the first bombing wave, and caused at least one aircraft to abort further attacks.

Barrage fire probably caused pilots to jink and thus reduce the accuracy of their bombing runs, but barrage fire was the only way for heavy guns to contribute to AA defense once aircraft got within the minimum ranges for effective computer control, or were engaged in steep diving attacks, where FC computers could not provide accurate prediction.

[dunmunro]

Duncan,
I read that 4-5 of the attacking planes crash-landed on return, because of heavy damage suffered. They were not repairable.
Do you have any more info on this ?

AFAIK, only one crashed or crash landed, in addition to the 3 shot down immediately, but several more were damaged to varying degrees, but were repairable, IIRC.

The post war RN battle summary does state that 2 aircraft crashed at base or en-route and claims that this was based upon access to IJN records and thus 5 were shot down, but most account state the above.

[Francis Marliere]

This same Air Group was cut to pieces in the Solomons in 1942 by American transport ships equipped with Bofers.* Allied ships would find the Bofers in large numbers indespensable as the war progresse

Gentlemen,

my bad, I read Dave's message too quickly yesterday and missed one point. As far as I know, the cruisers and destroyers that "cut to pieces" a Japanese Air Group off Lunga Point during Watchtower didn't have 40 mm Bofors, just 1.1" and 20 mm guns (as well as 5"/38 and 5"/25). There were very few Bofors afloat in late 42 (USS Enterprise didn't get some before October 42) and the guns weren't common untill 1943.

Best regards,

Francis Marliere

[Djoser]

Hey I wasn't the one to start making fun of choice of words.

But it's not a big deal, we are just posting opinions on an internet forum. I'm sure if we were all sitting at a table with a few beers or maybe a fine bottle of Schloss Vollrad, .

I've never had but will be glad to try some!

It would be my pleasure to buy us a bottle someday. It's the best medium grade German wine, and not too sweet at all--almost dry for a German white wine.

Getting back to the subject of AA, I remember reading that the British Navy fired off a prodigious amount of AA ammunition during the fighting north of Crete, so had to conserve ammunition during the fighting to the south of the island. I forget how effective the AA fire was though. Anyone know?

[Djoser]

McMullen's post action report is a bit misleading, as PoW's pom-poms did record hits on IJN aircraft, where the 40mm bofors didn't. Mcmullen noted that IJN aircrew were likely to take avoiding action when faced with tracer fire, but he doesn't actually note any 40mm hits. Of the 4 aircraft shot down by Force Z, pom-pom fire got at least two, and probably all 3 that crashed immediately, and possible the the 4th that crashed en-route to its base. Repulse's pom-poms got 2 of the aircraft, IIRC. The pom-poms biggest problem was defective ammo which greatly cut the effective RoF, and secondarily the lack of radar ranging for the Mk 4 pom-pom directors which had gyro lead computing sights.

The Pom-pom, with it's very large on mount magazines theoretically had a higher effective RoF than the Bofors despite a slightly lower maximum RoF.

Thanks for posting this.

I did recall that POW and Repulse didn't shoot down many planes, but I forgot it was quite that poor a showing considering both ships were sunk.. Comparatively speaking, the Bismarck didn't do so bad, when you look at a loss ratio of two sunk capital ships vs. 3 aircraft. The immense superiority of airpower to heavy naval vessels, especially when using torpedoes, was proven time and time again during the war. Which makes any discord on the subject rather fruitless. It took two strikes with maximum effort to cripple the Bismark, and not even come close to sinking him.

But still, regardless of whether his contemporaries had any better AA defense or not, if one could go back and improve any one thing, the Bismarck's AA would be the immediate choice!

[Francis Marliere]

Getting back to the subject of AA, I remember reading that the British Navy fired off a prodigious amount of AA ammunition during the fighting north of Crete, so had to conserve ammunition during the fighting to the south of the island. I forget how effective the AA fire was though. Anyone know?

I don't have the number of planes shot down at hands, but I would like to recall that the main purpose of AA fire is not to shoot down planes but to make them miss their target. Destroying planes is somewhat the 'cherry on the cake'. As for operation off Crete, my opinion is that British AA fire was effective because a lot of bombs missed their target.

Best regards,

Francis

[dunmunro]

McMullen's post action report is a bit misleading, as PoW's pom-poms did record hits on IJN aircraft, where the 40mm bofors didn't. Mcmullen noted that IJN aircrew were likely to take avoiding action when faced with tracer fire, but he doesn't actually note any 40mm hits. Of the 4 aircraft shot down by Force Z, pom-pom fire got at least two, and probably all 3 that crashed immediately, and possible the the 4th that crashed en-route to its base. Repulse's pom-poms got 2 of the aircraft, IIRC. The pom-poms biggest problem was defective ammo which greatly cut the effective RoF, and secondarily the lack of radar ranging for the Mk 4 pom-pom directors which had gyro lead computing sights.

The Pom-pom, with it's very large on mount magazines theoretically had a higher effective RoF than the Bofors despite a slightly lower maximum RoF.

Thanks for posting this.

I did recall that POW and Repulse didn't shoot down many planes, but I forgot it was quite that poor a showing considering both ships were sunk.. Comparatively speaking, the Bismarck didn't do so bad, when you look at a loss ratio of two sunk capital ships vs. 3 aircraft. The immense superiority of airpower to heavy naval vessels, especially when using torpedoes, was proven time and time again during the war. Which makes any discord on the subject rather fruitless. It took two strikes with maximum effort to cripple the Bismark, and not even come close to sinking him.

But still, regardless of whether his contemporaries had any better AA defense or not, if one could go back and improve any one thing, the Bismarck's AA would be the immediate choice!

PoW's air defence was rapidly degraded by the single torpedo hit to her port prop shaft that caused far more flooding than it should have. This was a very freak hit, and subsequent faulty damage control greatly exacerbated it's effects. The other 3 hits did very negligible amounts of flooding and internal damage. I don't want to change the discussion away from AA, only point out that had proper damage control been initiated (PoW restarted the damaged shaft and most subsequent damage from that hit was therefore self inflicted) her AA power would have been far less impaired, and the IJN strikes, more costly.

[alecsandros]

The other 3 hits did very negligible amounts of flooding and internal damage.

The bow hit caused some flooding, and more reduction in speed...

Is it certain that there were only 4 hits ? As I understand it, the second explosion was so violent and the wall of water so large, that most interpreted it as 2 torpedoes hiting simultaneously, or a torpedo exploding and causing the explosion of another one, in close proximity, but a little bit behind it. This double shock wave would be responsible for at least some of the flloding and damage suffered.

[dunmunro]

The other 3 hits did very negligible amounts of flooding and internal damage.

The bow hit caused some flooding, and more reduction in speed...

Is it certain that there were only 4 hits ? As I understand it, the second explosion was so violent and the wall of water so large, that most interpreted it as 2 torpedoes hiting simultaneously, or a torpedo exploding and causing the explosion of another one, in close proximity, but a little bit behind it. This double shock wave would be responsible for at least some of the flloding and damage suffered.

It is certain that there was only 4 hits; this was the observation made at the time and noted in PoW's bridge record of the action, and recently a survey of the wreck confirmed this.

The majority of the port side damage and flooding undoubtedly occurred after the shaft was restarted, and allowed to run at near full power, causing it to rip the apart bulkheads along the shaft passage right up to the engine room. There is a link to the report on the PoW wikipedia page. The starboard side hits caused some damage, but relatively little flooding or loss of electrical power and would have had no effect on PoW's firepower

However, I don't want to divert the discussion to PoW, other than to note that her AA power was unduly weakened by the port side hit.

[alecsandros]

However, I don't want to divert the discussion to PoW, other than to note that her AA power was unduly weakened by the port side hit.

I also think so...

[paulcadogan]

Here's a direct link to the latest edition (2012) of the report.

http://www.pacificwrecks.com/ships/hms/ ... update.pdf

[alecsandros]

Here's a direct link to the latest edition (2012) of the report.

http://www.pacificwrecks.com/ships/hms/ ... update.pdf

I know the report;
What I did not find was an attempt to explain the first 2 particularly violent explosions. In G&D's "Allied battleships", the theory presented is that such violent shocks, could only have come from 2 nearly simoultaneos torpedo warheads eplosions.
The second hit mentioned in the report is reported as being even more violent than the others.
Also, in the CG images inclued in the report, the second hit has a larger hole than the others.

There may have been only 4 hits, but I did not see any recent attempt at explaining the particular violence of the 2 hits... [which were considered by some as 4 hits, raising the total to 6]