Post ww2 subs and type xxi

Which post war designs were influenced by the Type XXI and to what degree? If it was never designed do you see the design of subs going the same route?
 
All of them and yes.

Pre radar submarines were really submersibles and so were mostly focused on high performance on the surface. The idea being that they would get into position on the surface and then submerge to attack if necessary, sub-surface manoeuvres mostly being tactical. Once radar equipped search planes were effective they would be expected to operate mostly underwater, and hence design parameters would follow. As an example of how inevitable higher underwater speed and the streamlined hull form were once underwater operations were prioritized have a look at the WW1 R class submarine.

The Type XXI influenced western submarine designs mostly as a way of exploring options by seeing what worked and what didn't and in developing anti submarine tactics against fast submerged submarines rather than directly copying, since both the UK and the US had extensive design and combat experience of their own. The USSR was more directly influenced, and used the XXI class as the design starting point
 
The first submarines designed for high underwater speed were the British R class. 12were built in 1917/18 and they can lay some claim to having been the first "hunter killer" submarines.
The Japanese worked in a similar concept with an experimental boat ( No 71) before the war and built to classes of high underwater speed submarines the larger type ST and coastal type STS.
The type XXI is just more famous, but all the ideas were also tested elsewhere and would have been adopted because they were clearly the next step in submarine evolution.
 
The R Class is one of those great 'what ifs' because after the War the RN said "We don't need it and thus no one else will!" and basically scrapped the idea and any research into it :( The XXI pointed the way forwards, it combined the technologies that were available into a whole unit.
 
I see the Klasse XXI as a reputation largely built on mythology, another German 'if only' 'wonder weapon' that would 'win the war'. And I don't see them being especially influential.

As @AdA stated, the R-class were the first high underwater speed subs. When Naval Intelligence got wind of the XXIs, the first thing they did was review the R-class jacket.

The XXIs were overly complex with over engineering, and a bad design. The figure-8 hull was never repeated. They originally were to be fitted with peroxide propulsion, but when that was abandoned (at the concentrations needed, it could dissolve humans) in favor of diesel-electric, it was crammed into a hull not designed for it. The batteries were very poor, and would have needed replaced after each voyage, assuming the sub survived. Internally, piping and wiring were behind paneling, where it couldn't be reached or repaired in a timely manner. Any sub expecting to be in combat should have them accessible.

In addition, construction was poor, an outgrowth of trying to disperse production; fit and welding were issues, both being poor. Water flow noise made them easy to detect once the Allies knew what to look for.

The Japanese I-201s were a better design, and built to higher standards, just as the R-class a generation earlier was. Arguably, those Rs outperformed the XXIs, and the I-201s were considerably superior. One thing the I-201s and XXIs did have in common though; they were both very hard to control underwater. Hard maneuvers could throw them out of control, and they could pass crush depth before the situation rectified.

A couple of S-class boats were modified for high (relative) underwater speed, and they were being tested before Klasse XXI was around. They showed what needed to be done to counter such a sub: 21 knot corvettes and destroyer escorts would be removed from service, replaced by 24 knot escorts, and there were plans to convert Benson/Gleaves and Mayo class destroyers to an ASW configuration with 2 x 5in, two large Hedgehogs in place of two 5in, two medium Hedgehogs on the waist and 20 DC throwers on the rails. Post-war trials showed they would have had a 30 per cent chance of killing a 'fast' sub on the first pass.

The S-boat modifications showed a US Fleet Boat or RN T-class could equal XXI performance with simple modifications. They showed the way to the GUPPY boats post-war.

Of course the real revolution in submarines was postwar the USNs Albacore (tear-drop hull) and Nautilus (nuclear propulsion). When they converged in Skipjack (SSN-585), submarines were changed forever.

My thoughts,
 
U.S.S. Trigger (SS-564) was built with engines similar to the Type XXI. Here's a comment on her:

. . . the new fleet submarines built during the early 1950s had been a hushed-up scandal; their diesels had been undependable, their torpedo control input erratic, their freshwater distilling apparatus farcially ineffective, their torpedo tubes a maintenance nightmare. The skipper of the first one to go to sea, an experienced wartime submariner, had furiously radioed in during her shakedown cruise that his new boat was a travesty not fit for service — with the shattering result that he was severely dressed down, nearly relieved of command, for excessive forthrightness.

“Later on, a couple of that class had to be towed back to port, one all the way from England, so he was sure right,” said Richardson. “The Navy made it up to him with the Triton.

-- Cold as the Sea, Edward L. Beach

Who is also the captain being talked about. That's right, the author had his characters talk about him.
 

CalBear

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The change in design/mission was inevitable, the fairly shocking thing is actually that the WAllies, especially the RN, didn't incorporate the snorkel into their later wartime designs. The RN had FOUR O.21 class Dutch subs that had escaped, while still uncompleted, to the UK when the Netherlands were invaded. Worse, the British actually completed all four of them, including at least one in an actual Royal Navy yard and they then operated under the Dutch Flag, for the rest of the War. The WAllies had the damned snorkel sitting in their hands for five years. Absolutely no reason that the U.S. Tench class and even a Balao derived sub-class couldn't have been equipped with snorkels by 1943.

The German captured three of the O.21 class boats which is where their snorkel design was based.

What eventually clinched the change, however, was nuclear power, which led directly to the "Albacore hull".

 
The R Class is one of those great 'what ifs' because after the War the RN said "We don't need it and thus no one else will!" and basically scrapped the idea and any research into it :( The XXI pointed the way forwards, it combined the technologies that were available into a whole unit.
The R class could have lead to the RN developing submarines optimised for offensive Hunter Killer mission agains U-Boats deploying from their bases in WW2
 
The R class could have lead to the RN developing submarines optimised for offensive Hunter Killer mission agains U-Boats deploying from their bases in WW2
That would require questioning the complacent orthodox belief that the combination of convoys and asdic had neutered the submarine threat to Britain. You also have to persuade the treasury to fund a lot of expensive r and d into solving a problem the Admirals are saying has already been solved.
 
That would require questioning the complacent orthodox belief that the combination of convoys and asdic had neutered the submarine threat to Britain. You also have to persuade the treasury to fund a lot of expensive r and d into solving a problem the Admirals are saying has already been solved.
It would also be giving others obvious ideas, anybody can realize that an R class isnt going to be using cruiser rules........ Why work on this like subs that obviously hurt nations like GB that rely on ships?
 
That would require questioning the complacent orthodox belief that the combination of convoys and asdic had neutered the submarine threat to Britain. You also have to persuade the treasury to fund a lot of expensive r and d into solving a problem the Admirals are saying has already been solved.

Aye that's the problem! The RN was absolutely sure that ASDIC was the be all and end all solution for the submarine threat, and IIRC they held some heavily biased exercises to 'prove' this. I do recall reading somewhere that the RN did look at an ahead throwing weapon some time in the 30's but felt it wasn't needed so stopped development too.
 
It would also be giving others obvious ideas, anybody can realize that an R class isnt going to be using cruiser rules........ Why work on this like subs that obviously hurt nations like GB that rely on ships?
The use of Hunter Killer submarines is a deterrent. They would force the nations using submarines against trade to protect their bases from yet another threat. Submarine bases would now have to house ASW assets to create a bastion defense that kept hunter killer subs away.
Those ASW assets would then in turn need to be protected from enemy surface raids, and so on.
 
I think it's a shame that the RN never fielded a hunter killer variant of the small U class submarines in the Med and North West Europe. The Y class perhaps. More batteries, streamlined casing and higher powered electric motors.
 
The use of Hunter Killer submarines is a deterrent. They would force the nations using submarines against trade to protect their bases from yet another threat. Submarine bases would now have to house ASW assets to create a bastion defense that kept hunter killer subs away.
Those ASW assets would then in turn need to be protected from enemy surface raids, and so on.
But the exact same subs are perfect for say France (or Italy the med) to try and blockade GB merchant shipping.....

Basically HK subs mean you are planning to fight underwater with torpedoes only, at that point the WNT/LNT/etc attempts to get subs banned or limited to cruiser rules are gone and RN/GB would never want to be first to do that?
 
Aye that's the problem! The RN was absolutely sure that ASDIC was the be all and end all solution for the submarine threat, and IIRC they held some heavily biased exercises to 'prove' this. I do recall reading somewhere that the RN did look at an ahead throwing weapon some time in the 30's but felt it wasn't needed so stopped development too.
Is it not more that basically all weapons development was stopped (or drastically slowed down) in interwar due to funds (look at how long it takes for the 16" N&R guns to be fixed with actual money spent on them), GB was trying to get treaties to limit subs out of use, so then got far to complacent in 30s for far to long, just like they did with 14" guns and BBs, when they started to actually believe the paper was worth something...?
 
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But the exact same subs are perfect for say France (or Italy the med) to try and blockade GB merchant shipping.....

Basically HK subs mean you are planning to fight underwater with torpedoes only, at that point the WNT/LNT/etc attempts to get subs banned or limited to cruiser rules are gone and RN/GB would never want to be first to do that?
Commerce raiding required long patrols on the surface, gun armement, and a decent surface speed.
HK submarines would be seen as a British curiosity, and not fit in with most other navies requirements
If the French ans the Italians decide to build some HK subs to chase one another in the Med, fine.
The Germans would probably build boats based on their best WW1 designs, as they did OTL.
The IJN tested the idea in the late 30s and didn't follow it until 1944.
 
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Commerce raiding required long patrols on the surface, gun armement, and a decent surface speed.
Not against GB from base in France if you are willing to go for USW rather than Cruiser rules...... Really, HK Subs would be very useful for a close blockade of GB ports from Europe or Malta from Italy?
 
Not against GB from base in France if you are willing to go for USW rather than Cruiser rules...... Really, HK Subs would be very useful for a close blockade of GB ports from Europe or Malta from Italy?
They would lack either decent detection/identification of targets or coms to locate shipping.
HK with WW2 tech would be limited to ambush tactics in small areas. They would be useful to ambush enemy subs out of their bases, but the western approaches to British Harbors are to wide open.
And their main attack tactic, salvo firing underwater based on predicted target positions using acoustic sensors, would be terrible wasteful for anti shipping missions.
The R had six 18'' bow tubes with one reload per tube, giving them basically two antisubmarine salvos.
For the conditions of the BoA, the OTL type VII were actually very well suited.
 
The Type XXI had only a small influence on post WW2 boats. Since the US/UK had pioneered modern ASW they knew that boats would need to spend almost all of their time underwater. This led them to make their own design changes. The US was also pursuing nuclear power. The Nautilus was underway on nuclear power in January of 1955. After this hull design really didn’t matter. The Skipjack class had a “tear dropped” shaped hull, but the US classes since have not. 594, 637, 688, Seawolf, and Virginia were/are all basically straight metal tubes with a fiberglass sonar dome and tapered at the stern. Except for 688s and Seawolf they were designed to be around 27 knots top end and stealth. 688 class was designed to escort US CBGs. The thickness of the hull was reduced for a higher top end. They maxed out around 33-36 knots. Seawolf was designed to be, well amazing. It was nicknamed SFFSFO (So f$&@ing fast sh@t falls off) by the guys who built it. You would be amazed to know how fast they really are. They are also super stealthy. Virginia’s were designed to be cost effective, no refueling, and quiet. The SSN(X) is going to be wider for more volume. It will probably have one electric motor instead of steam turbines. The stern planes will probably be “X” shaped. (Don’t know how much more maneuverable they will be. A 688 doing snap turns at ahead flank would throw people out of their racks. They were so powerful the ship torqued around the shaft on flank cavitate bells.)
 
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