Das Boot or the American Fleet Boat

[Krauter]

As someone mentioned earlier in the thread, the two submarines are very hard to compare because each was designed to meet specific needs of it's theatre.

Thus it's like comparing (vague comparison coming..) a crocodile to a dinosaure. Sure they're related, but both predators come to meet different criterias of their region and age.

One point that boggles me is that yes, the earlier Type VIIA and possibly the Type VIIBs cannot really be compared to subs like the Gato, Porpoise, etc. But once the U-Boat operations started running out into the Atlantic Gap (now strictly talking of VII operations, not IX which could actually be compared to Gatos) the operational framework starts to look similar to that of the Pacific. Find, Fix and Destroy convoys and targets of opportunity in the middle of the ocean.

Thus, how do such subs such as the VIIC, VIIC/41 and the planned VIIC/42 compare to the Gatos and their contemporary American cousins.

Secondly, I understand the great difference that Radar makes for the Americans, but I'm really amazed to see that such simple (well not really simple..) things such as diving depth (really a Type VIIA can dive deeper then a Balao..) are greatly different between the two.

Question for you naval types: With the fleet boats larger size, would it not then offer a better chance at diving deeper then the smaller Type VIIs? What is the difference maker here?

I am really interested in the differences between the two campaigns and how they affected the ships that fought them, to this thread

Krauter

Could it be the differances in tactics in the interwar period?

The americans most likely subscribed to the traditional theory of submarines, their role was to sit at periscope depth outside of the enemy home harbor and sink ships of the line as they sailed out for one big battle. The idea was that they were like torpedo boats that could hide for a bit, not roaming underwater death machines.

The germans thought this way as well, but due to the foe being much more obvious and the tactics based much more on attacking escorted supply convoys submerged and getting away underwater, the focus was indeed on long term underwater ops and a deeper diving depth would be needed.

Still cant for the life of my figure out why radar would be a bad idea. If you suspect air activity in the area than switch it off, why deprive yourself of a tool?

[Piggy]

Yeah Ive always found that a bit odd that the fleet boats max depth was well under that of u-boats...

However, could the explanation simply be that the germans had a lot of prior experience with submarines, at war.

What were the diving depths of WW1 U-boats?

Edit: According to U-boat.net the UB III's (most produced of WW1) had a max depth of ~250' (75m).. so not very deep. These boats are quite similar to VII's.

http://www.uboat.net/wwi/types/index.html?type=UB+III

[tater]

Could the VIIA actually dive deeper? Balaos dove far in excess of rated depth and survived, and post war boats which were little different went deeper still.

I think like radar in actual use, this is more necessity than anything else—not of design, but practice. Had the US faced better ASW, our boats would have gone deeper and deeper since when the alternative is certain death, risking a deeper dive is a chance worth taking.

As was said, comparisons are hard due to the situations faced. Seems like the added range and stores in the Fleets would have proved very useful since simply getting to sea was often troublesome for u-boats. Once there, duration on station would be desirable, right? I assume the allies paid special attention to patrolling approaches to u-boat bases. Were they successful in sinking many that were coming or going from port?

[Krauter]

For diving comparisons I`m just assuming the designed crush depth of 200m for VIIAs (220 i believe for VIIC's). Whereas the Balaos was somewhere around 600-650ft.

If I am wrong by all means correct me. Because with the arguments that Balaos could go under the 650mark, the argument that VII's went under the 200m mark is perfectly plausible as well.

Edit: In regards to your earlier post on this page tater.. it's kind of like a damned if you do damned if you don't situation . I have somewhere in a book at home a quote which I will post later on a description of the U-Boat Kaleun. These men are truly magnificent example of bravery and courage

[tater]

I read in Friedman that the limiting factor on Fleet Type depth was actually the trim pump (which was based on a German design) seeing as it's not just the hull, but also every penetration that might leak. They made a new type of trim pump in 1944, and were much better off. I think the actual crush depth was beyond 675 feet.

It's tough, as I don't think either side destructively tested real boats, it was all sort of theoretical, whereas in practice, skippers on both sides went well below "sanctioned" depths.

You also have to be careful with production stats vs wartime use. US battery specific gravities were changed from the peacetime value upwards, increasing storage capacity, for example. So the time at 2 kts in the manual would be wrong if based on the lower sg. I'm sure there is loads of that on both sides.

[Bilge_Rat]

AFAIK, the deepest dive of a type VII (that came back up) was U-331 in november 1941. After it sank HMS Barham, it dived to 250 meters (820 feet).

The Balao class could dive to 600 feet and one accidently dived to 1011 feet and survived, although the hull was so damaged, it was taken out of service.

http://www.usschopper.com/Chopper%20...e%20Report.htm

[Rockin Robbins]

Re: Radar. Let's take a tactical look at the situation. You're on a submarine, tracking an aircraft carrier by radar. Perhaps you even know that the enemy can detect your radar. What do you do? What did the real skippers do?

As the user of radar, you know the course and speed of every enemy on the scope. You can plan attack and evasion with great flexibility. You can be much less optically visible by remaining at radar depth as you do so, or retain 21 knot speed by remaining on the surface.

The enemy with a radar detector such as the Japanese used in WWII knows only one thing: there's an American sub out there. This could be crucial information, but it is also a double-edged sword, sometimes pressuring the commander of the target into deadly blunders.

Read Shinano by Joe Enright, skipper of the Archerfish and you'll see that the above situation is not fictional, it is exactly true. Enright knew the enemy could detect his radar and so left it on! The enemy, detecting the radar, reasoned that a sub would only have its radar on if it were shadowing and spotting for a large wolfpack looking to sink the Shinano.

Based on that erroneous decision, the Japanese admiral aboard Shinano proceeded to make decisions which resulted in Archerfish being in the exact position for a very high probability spread. Had the admiral just kept a straight course and accelerated, Enright never would have had a chance.

The decisive factor? Enright had a complete combat picture, where the Japanese had only one fact to deal with. Advantage Radar. Blub! Blub! Blub!

The American fleet boat took enough ordinance to battle to equal a Type VII PLUS a Type IX. What's a sub with four forward torpedoes going to do confronted with a convoy of 500 ships? Not a lot. What are 20 subs going to do? Not a lot. In practice they got one spread off and were driven harmlessly to that extreme depth the Germans were so proud to boast about.

A submarine driven deep is a harmless thing, moving slow. It cannot keep up with the convoy and the battle is over. Deep diving capabilities, rather than being tactically useful, were little more than an "ours is better" talking point.

AA guns on submarines are good for sinking sampans, something the Germans didn't have to shoot at so their weaponry was useless. By their intimidating appearance, they encouraged the poor captain to decide to shoot it out on the surface.

So the big expensive submarine shoots down a cheap replaceable airplane. Before the attack the airplane radioed the positon of the spotted submarine, which had foolishly remained on the surface to demonstrate its manhood. What do you think happens next? Blub, Blub, Blub! One expensive, hard to replace submarine, filled with irreplaceable highly trained crewmembers traded for a couple of popcorn-like aircraft. What a bargain! That's called owned nowdays.

The U-Boats chatted on the radio like a gaggle of Japanese schoolgirls, secure in the knowledge that the superior German intellect could not be outwitted by the hapless Brits or soft Americans. This "superior feature" alone doomed the entire fleet.

Time after time the supposed advantages of the U-Boats were central to their defeat. Even their 2 to 1 hits percentage superiority had no effect because they did not have enough firepower to make a difference.

I would say a very good argument can be made that U-Boats were a total waste of money and good men for the Germans who could have used the resources to make a decisive difference in the ground war.

In fact, I would say that the Germans, equipped with a fleet of Balaos, would still have lost the Battle of the Atlantic decisively. The Americans with a fleet of Type IXs would have had a much more difficult time defeating the Japanese.

This is not to say that the U-Boats were not marvelous and fascinating machines. They were. They accomplished WAY more than anyone, especially the Brits, expected. In spite of that, from the first "torpedoes los" the German submarine fleet was doomed. Reallocating resources to beef up the ground war MIGHT have made a decisive difference. Thank God it didn't happen.

[Bilge_Rat]

Originally Posted by Rockin Robbins

The U-Boats chatted on the radio like a gaggle of Japanese schoolgirls, secure in the knowledge that the superior German intellect could not be outwitted by the hapless Brits or soft Americans. This "superior feature" alone doomed the entire fleet.

very good post RR.

On that last point, the Allies were observing how the German U-Boats were being handled, centralized control, regular radio reports, propaganda articles full of details on particular patrols and the US submarine service decided to go the other way, namely total secrecy.

It was too easy to break naval codes and read radio traffic, plot the location of U-Boats through RDF and glean info on tactics through newspaper articles.

That point was driven home in the early winter of 43 when a new sub commander took over in Australia who insisted that his subs send in daily location reports so he could control their movements. Within a few weeks, 3 fleet boats disappeared north of New Guinea. It was surmised that the new orders might be the reason, so the subs went back to near total radio silence and the said commander was shuffled off to a non-combat role.

After looking through the japanese records after the war, it was surmised that the location of the subs had been pinpointed by the excellent japanese RDF network.

A big part of the reason why US submarines were so successful in WW2 was due to smart leadership.

[Noren]

Thats a great post, but how can you be so sure of yourself?

First: the japanese fleet knew that there wasa sub out there somewhere and radio/radar-detectors could generally give the bearing. If they have numerous bearings simultaniously they can triangulate the subs position and locate it.
Even without triangulation, the captain could have sent a patrol of destroyers after the sub. This is all only theories but logical ones and the japanese commander made an error.

Next you speak of convoys of 500 ships? Only in the very end of the pacific war have I heard of such concentrations of ships, namely american taskforces. Early in the battle of the atlantic, convoys were often 10-50 ships and lightly protected, so even few uboats could wreck havoc there (like Kretschmer did during nightattacks).

One could argu that if Döntiz had even more uboats, with working torpedoes at the onset of the war, before effective asdic, DC, fast shipbuilding, enigma codebreaking and naval aircraft patrols perhaps England indeed would have been severly cut of - like Churchill feared.

Shift resources from the navy to the army? The navy was small to begin with. I dont think what would have much an impact, perhaps a few more panzer divisions and perhaps 10 more infantry divisions but it would'nt had halted the russians or made much of a strategic differance when germany was fighting on 3 fronts.