In WWII, How Effective Was the Foxer in Defeating Homing Torpedoes? (war, influence)

[Exitus Acta Probat]

How effective were they? If, for example, a U-Boat fired a Type V torpedo at a destroyer towing a Foxer, what were the approximate odds the torpedo would go for it instead of the destroyer?

[MidValleyDad]

As I understand it from what I have read and heard frominterviews with crew members of Escorts it was VERY effective (and cheap) probably above 80% effective

[Exitus Acta Probat]

That is quite effective.

[MidValleyDad]

I believe my 80% is probably conservative. I vaguely remember one article claim that no escort actually using foxer was ever hit.

[Cryptic]

I have also read that they were very effective. The only draw back is that the devices were large and created a lot of drag. This slowed down the escort.

Originally Posted by Exitus Acta Probat

How effective were they? If, for example, a U-Boat fired a Type V torpedo at a destroyer towing a Foxer, what were the approximate odds the torpedo would go for it instead of the destroyer?

I don't mean to nit pick, but....

Modern fleet destroyers (true destroyers) were rarely used against U boats. Rather, a variety of obsolete destroyers, corvettes, frigates and destroyer escorts (DE) were used. These ships often had less powerful engines and in some cases, near failing engines in the case of the WWI surplus flush deck destroyers). As a result, the speed reduction from the foxers was noticeable.

[NJGOAT]

The data is hard to come by, because it is difficult to know exactly how well the counter measures worked. This article details some of how the torpedoes worked as known by the allies and the development of counter measures and their effectiveness.

https://www.ibiblio.org/hyperwar/USN...51/ASW-15.html

While the counter measures were highly effective (over 90%) in lab testing, in the real world the numbers were more subdued. We know that approximately 40% of all torpedo hits from Sept. 1943 to May 1945 involved T5's. Of those 32 hit ASW ships and 19 hit merchant ships. Of the 51 total, 7 were employing active noisemakers, 4 were travelling at under 9 knots (effectively lowering their sound signature and making them difficult for the torpedo to pickup) and 40 were not employing any countermeasures at all.

The issue is that we don't know how many T5's were fired in total to see how those numbers might compare. The German records and postwar interrogations lead to a wide variety of estimates of success. The Germans themselves seemed to chalk up most of their failures as duds. At the same time they developed tactics to specifically go after ships employing counter measures showing that they certainly influenced German thought.

Side note...of interest in the table at the linked article is the sink rate. Against warships T5's had a hard time actually sinking a ship. Most of that seems to be tied to the fact that T5's mainly impacted the rear of the ships, where it was easier for damage control to save the ship, and the smaller charge that they carried causing less damage.

[Exitus Acta Probat]

Interesting -- thanks.

BTW, was firing T5's at merchants frowned upon by BDU, since a T3, T2, or T1 was a more economical choice and merchants generally traveled too slowly for the T5's homing to work? However, if a U-Boat captain only happens to have T5's loaded, then there's of course no choice in the matter since it could take 20 minutes to unload, then reload any given tube.

And, if a T5 was homing in on a destroyer and accidentally plowed into a merchant, that's another matter too.

[NJGOAT]

Originally Posted by Exitus Acta Probat

Interesting -- thanks.

BTW, was firing T5's at merchants frowned upon by BDU, since a T3, T2, or T1 was a more economical choice and merchants generally traveled too slowly for the T5's homing to work? However, if a U-Boat captain only happens to have T5's loaded, then there's of course no choice in the matter since it could take 20 minutes to unload, then reload any given tube.

And, if a T5 was homing in on a destroyer and accidentally plowed into a merchant, that's another matter too.

According to statements made to the Allies during the war by German POW's, the T5's were to be used against the escort ships and then more conventional munitions could be used against the remaining merchants. This is why counter measures were primarily developed to be used by escort vessels, since it was believed that they were the intended target. German documents of the time however, show that this was not the case. T5's were not designated solely for attacking escorts, but the noisy escorts certainly tended to attract them.

[Cryptic]

Originally Posted by Exitus Acta Probat

Interesting -- thanks.

BTW, was firing T5's at merchants frowned upon by BDU, since a T3, T2, or T1 was a more economical choice and merchants generally traveled too slowly for the T5's homing to work?

Firing T-5s against merchant shipping was frowned upon and U boat captains were instructed to save them for escorts. At the same time, Doenitz gave U boat captains near total local discretion when making attacks. As a result, T-5 uses against merchants were probably ignored- espescially when the T-5 was introduced, many U boats were lucky to be making any kind of successful attack and returning home.

Originally Posted by Exitus Acta Probat

However, if a U-Boat captain only happens to have T5's loaded, then there's of course no choice in the matter since it could take 20 minutes to unload, then reload any given tube.

I think having all five tubes loaded with T-5s would have been very unusual. T-5s were specialty weapons and were in short supply. Initially, each U boat was only given one or two of them. Though production did increase, it never reached the stage where enough T-5s were available to make them the standard battle carry.