Tirpitz AA Fire

[Dave Saxton]

Tirpitz's 20mm Veirlings were a significant improvement for at least two important reasons. One is the fact that the most effective flak on warships during WWII was the light flak with relative high total rates of fire, rather than heavy flak batterys. The German 20mm veirling would prove a very effective AA weapon through out the war. The other factor that placed importance on Tirpitz's improved light flak capabilities in this case was the fact that the aircraft were able to approach hidden by the low over cast as previously mentioned. This means that the heavier flak weapons had relatively very little time to fire on the attackers as compared to a more normal daytime torpedo attack circumstance.

Although it's true that the swordfish in the Bismarck's case were attacking in bad weather, the Swordfish also should have been able to mask their approach using the weather and tracking their target using airborne radar, as the Albacores did vs Tirpitz. Despite the fact that the Swordfish were fabric covered biplanes they possessed airborne radar. The air to surface vessel radar was called ASV-II operating on a wave length of 140cm. When approaching the Bismarck’s location, the aircrews had detected a radar contact, so emerging from the rain clouds they began to line up the first warship found below. It was with frantic signaling by the cruiser Norfolk that the aircrews were informed that the ship was a British warship and not the Bismarck. They repeated the same error a few minutes later when emerging from the cloud they found that the corresponding radar contact was in fact the American Coast Guard ship Modoc, before going on to the attack the Bismarck a bit further on. This illustrates a problem that few had given much thought to. Radar contacts are nothing more than squiggles on traces, or blips, on the indicators, and they do not readily indicate what the contact really is, or if it is a friend or a foe, or perchance a neutral. Thus the attacking air groups did not have the element of surprize by the time they were finally ready to attack Bismarck. Bismarck probably had detected their approach anyway.

[Bgile]

US heavy flak shot down about 25% of the total in the Pacific. Many of those were shot down before they were in range of the light flak, and some of the kills by light flak were undoubtedly aircraft already damaged by heavy flak. Heavy flak also forced attackers to maneuver, making their attack less effective than it might have been otherwise.

While it's true that the numbers favor the light flak, the heavy flak contributed a lot, especially considering it was a dual purpose weapon.

[Dave Saxton]

I don't disagree Steve. A good point. Tirpitz's heavy flak may have been able to contribute in like fashion had it had more time to target the aircraft during their approach. Bismarck's heavy flak was probably not able to develop its (somewhat lesser) potential either oweing to the adverse weather. This placed an even greater burden on the light flak in the specif cases of Bismarck and Tirpitz, and Tirpitz's light flak a year later was much more capable than Bismarck's.

[Bgile]

It's also probably true that the weather in the North Atlantic made light AA even more important than in other theatres because of that increased likelyhood of air attack under poor visibility conditions.

[Francis Marliere]

US heavy flak shot down about 25% of the total in the Pacific.

Bgile, could you please tell me your sources ? I am interested by the subject and surprised because I was inclined to think that prior the introduction of VT fuze, heavy flak was not very effective. I think that according to South Dakota AAR for the battle of Santa Cruz, 5" guns shot down only 5% of ennemy planes destroyed by US flak.

Best regards, and thanks in advance for your precisions,

Francis

[lwd]

South Dakota's claims resulted in considerable "debate" in both the historical comunity and the USN at the time. In general beware of claimed kills especially from units or ships with problematic records in that regard.

There are a couple of threads here where we got into the AA area pretty deeply. Included are some good links.

[Bgile]

Here is one of them (a little different from the one I recall, but in the same ballpark):

http://www.history.navy.mil/library/onl ... y_wwii.htm

[Thorsten Wahl]

The official statement
MDV 601 Heft 13 Operationen von Flottenstreitkräften im Nordpolarmeer im Jahre 1942

[José M. Rico]

Can anyone give us an English translation?