IMHO there is no WWII sub that can beat XXI :arrgh!:

Gato vs Ix boats, perhaps iXD

type VII must be compared with other us boats like P- class or barracuda.
but a true comparation is difficult because us boat were bigger than german boats.
for example s-class, about 900 tons , 12 torpedoes, and 14- 10 knts (from sh1)

XXI boat has not comparation with other ww2 submarine. because was the first modern submarine and not very different with actual diesel/electric concept (except the new AIP boats)

Well it`s very hard to compare the VIIs and Gato/Balao/Tench. They`ve been designed for totally different areas and therefore have little in common. Just notice the range issue - Gato wouldn`t have problems operating in the Atlantic while VII would have to spare fuel in order to operate in the Pacific.
Just for that, I guess it`s better to compare type IX to American projects.
IXD2 had superior range than Gato. Additionally, lower mass and ability of going deeper would make them more difficult target for ASW. And keep in minds, that all ASW means the Japanese had can be compared to the Allied of 1939-41 when we speak of quality, availability or numbers.
Another important aspect is the offensive potential and ability to intercept enemy targets. Here, Americans win. Sure, German attack periscopes were a piece of art and excellent design but you just can`t beat American radar equipment. Additionally, American conning towers were a little bit higher so even if we forget about the radar for a moment, Americans earn another point. Additionally, slightly higher maximum speed and more torpedo tubes mean more chances for interception and succesfull attack.
Then, comfort of the crew. In this term, Americans win easily. There was much less space in the German subs and in general the conditions were harsh.


In general, American subs may seem better but we should not forget about two important factors:
1. Japanese ASW were very poor when compared to the Allied ASW, especially late in the war. I bet American subs in the same conditions the U Boats suffered from 1943 on would have had the same or even higher loss ratio with not more successes.
2. Typ XXI was actually in all aspects way more advanced than any other sub of the time. So I guess this wuold be the ultimate winner of the competition :D

IXD2 Vs Gato is the only fair comparision. If one was to look at their specifications and dimensions, one would find they are very similar.

I agree w/ Ducimus.

The thing that I have been wondering, and haven't been able to find a good answer, or ever a bad one, anywhere is which boat was quieter at depth.

Anyone have any angles on this?

I'd give up a 100 feet of depth to have the extra four tubes anyday, not to mention the climate control....

I have been on board both a German U-Boat (U-505 a IXC) and an BALAO class Submarine (USS PAMPANITO) I was also aboard USS Growler (build just after WWII). Both are combat vets.

The German boats were impressive, espically all the toys they built for them later in the war such as Snorkel, the various pattern running and Homing Torpedos, it was all state-of the-art.

But I think in basic submarine design, the US boats were superior.

They had the better range, better speed, (Dive depth was about equal) were much faster both underwater and on the surface and were better armed. Also I believe the US had the advantage with a superior TDC. It was less accurate than the Germans but could provide a solution faster and target corrections could be transmitted via the pariscope.

The US also had better, and readily available search radar.

One thing nobody has mentioned is relibility, Espically the engines. The American GM diesels were incredibly reliable engines.

In terms of living space, the Gatos were much roomier. I thought space was pretty tight in the U505 boat (espically if you are 6'2). The USS Pampanito was much easier to move around.

No. But, the Americans had the equipment to detect and use a thermal layer to their advantage. This alone should be enough to give the boat a huge tactical advantage over a U boat.

I dont believe the Germans did that.

I practice, I wonder how many US subs on war patrols during WWII actually had bathythermographs installed? I recall reading an interview with a WWII German U-boat captain, that the Germans were well aware of the thermal layer phenomenon, and that getting under them was advantageous. However, the only way they knew they were passing through one (thermal layer) was if they observed a temperature fluctuation on the thermometer.

I'll have to see if I can dig that old article up.

Well, at least the USS Pampanito did as its use is mentioned several times in the excellent book, USS Pampanito, Killer-Angel".

Barkhorn.

Probably every fleet sub that went back into port for a refit.

Scorpion SS-278

"Following further yard work and fitting out, Scorpion conducted shakedown operations off the southern New England coast during January 1943 and sailed for Panama in late February. In mid-March, she transited the Panama canal, and, on 24 February, she arrived at Pearl Harbor. There, she underwent modifications which included the installation of a bathythermograph, a then new oceanographic instrument to enable her to locate and hide in thermal layers that minimized the effectiveness of SONAR equipment."

Great discussion going here!!!

A couple points I'd like to make:

1. The deep diving depths of the U-Boats was due to the fact that they had to go that deep for their very survival. US boats typically weren't subjected to ASW attacks as deadly as the assault of Allied Hunter-Killer groups. The Allies simply had better electonics. Go to www.de220.com for specifics as to WWII ASW capabilities. US subs could go very deep (Puffer: Gato Calss 500 ft, Tang: Balao Class 700 feet, Pollock: P Class 500 feet) but they weren't forced to do so as the U-Boats were. Not that going through a depth charge attack on one would be any less terrifying than on the other.

2. USS Seawolf. The only US sub to be sunk in the Pacific by an Allied escort the DE Rowell (I think). The Rowell had all the latest in ASW electonics and weapons (hedgehog/teardrop depth charges). It didn't take too long to put the Seawolf on the bottom...

From my understanding, thermel layers exist in both the pacific and atlantic, however the layers in the atlantic are MUCH DEEPER then in the pacific. Deeper then what submarines of the era could dive to. If i have that correct, then the germans (nor the american's) could exploit thermal layers in the alantic regardless if they had the gear to detect them or not.

I wonder why the thermal layers in the Atlantic would be deeper than the Pacific? I'm not saying this is incorrect, I'm just wondering why.... :hmm:

Thermal layers are not static nor are they exclusive per ocean.

The Thermalcline can vary from 30 to 400 meters with the the majority of them occuring towards the top of the range. 30 to 100 meters.

I doubt the entire Atlantic is under 200 meters constantly. Unless of course you are next to shore at which point surface disturbance and seasonal change can destroy the thermalcline altogether. There are also currents like the gulf stream that will effect the level as well. Off the coast of New jersey for instance the thermal cline often hovers close to 30 meters accept during the winter when it can disappear completely.

The best way to hide from surface vessels is to find and go into the layer or under it. U Boats just didnt do it where as US fleet boats had the equipment and knew how to use it. That is a huge adavantage.

"Ocean temperature varies with depth, but at between 30 and 100 meters there is often a marked change, called the thermocline, dividing the warmer surface water from the cold, still waters that make up the rest of the ocean. This can frustrate sonar, for a sound originating on one side of the thermocline tends to be bent, or refracted, off the thermocline. The thermocline may be present in shallower coastal waters, however, wave action will often mix the water column and eliminate the thermocline. Water pressure also affects sound propagation. Increased pressure increases the density of the water and raises the sound speed. Increases in sound speed cause the sound waves to refract away from the area of higher sound speed. The mathematical model of refraction is called Snell's law."

From this article in Wiki: http://en.wikipedia.org/wiki/ASDIC

I don't know what it is about the fixation over German subs going deeper than American boats. The Pacific war was nothing like the Atlantic war. Alot of the times the US boats were operating in waters that were too shallow for them to reach maximum depth anyway.

As for survivability I'll take the Gato/Balao class over any any German boat. How many German boats took multiple hits from 8 inch shells and lived to tell about it? A US boat did...course it was considered unrepairable and scrapped once it returned to port...but it did make it back.

How many German boats were pounded by DCs for over 24 hours some of which were no doubt 600 pounders and survive? The Puffer did.

Don't sell the US sub designs or their crews short.

Bottom line,the Germans for all thier vaunted technology failed to starve out England in approx 6 years of warfare. The US Subs starved out Japan,which had the third largest merchant fleet in 4 years. Approx 1 1/2 of those years was fought with defective torps. And the US did it with far fewer subs.

Which means that the Gato/Balao class were superior to the german boats in one major way...they succeeded,the type VIIs and type IXs failed.