WI:Krigesmarine type xxI

Discussion in 'Alternate History Discussion: After 1900' started by HMS queen Elizabeth, Nov 9, 2018.

  1. HMS queen Elizabeth Admiral vasieo Ignite the inferno.

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    What if the Krigesmarine gets the type 21 in 1943? Would the battle of the Atlantic go worse for the allies?
     
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  2. Astrodragon Coffee-seeking Dragon Donor

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    It's too late.
    By then the allies have beaten the U-boats and are sinking them at a rate of 40 a month.
    Type 21 would help a little, but sinking a few more ships isn't going to win the battle.
    The type 21 isn't a magic invulnerable sub, it has weaknesses. The British 2nd gen a/s frigate, the Loch class, was deadly against post war subs until the mid-50's. The Type 21 isn't as capable as those submarines.
     
  3. Riain Well-Known Member

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    If the Type XXI was introduced in 1943, and it was something of a surprise and deployed as such, then all the tactical developments and shipbuilding up to 1943 (the year the Allies won the BoA) would be for naught and they'd have to start again. This would give the Germans a new lease on life in the BoA, the Allies would no doubt beat them again, the the point is that they'd have to.
     
  4. ShockTrooper262 Well-Known Member

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    The allies already have the Mark 24 'Mine' deployed in use of ASW Operations, and due to the XXI's speed while submerged, I feel as if the Mark 19 Torpedo won't be passed in favor of the 26 torp. Either way the USN has a 29 knot homing torp that is still in testing in 1942, and a acoustic torp in use by 1943. The British also have dabbled in streamlined submarines so the RN and USN will be able continue winning the BoA. The Type XXI sets them back by a few months, but the Type XXI still would have teething problems and so the normal U-Boats get to play with USN ASW Torps that are significantly faster than they are.
     
  5. Cryhavoc101 Well-Known Member

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    Yeah March 43 sees a perfect alignment of the planets for the Allies regarding the BotA -at the time OTL the U Boats were winning but by May they had been beaten and stayed beaten.

    They hit the required number of escorts
    Escort carriers are introduced in significant numbers - allowing many convoys to have aircover
    New Freighter numbers particulalrly US built ones start to increasingly exceed losses - and these ships are generally faster and more capable than the vessels they are replacing.
    The RCN escort forces matures as a effective ASW force around this time
    The USN escort forces matures as an effective ASW force around this time
    Significantly LR Liberators are prized from the bomber commands of the RAF and USAAF along with other suitable aircraft basically eliminate the Black Gap
    New weapons such as the Porcupine coupled with new tactics make said escort forces much more effective in the attack
    In March 43 the FIDO is introduced and for every 6 of these air dropped homing torpedoes used in action 1 U Boat is sunk or damaged - in fact - it is so effective that the number ordered are significantly revised down from 10,000 to 4,000
     
  6. thaddeus Well-Known Member

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    my view they should have attempted the smaller Elektroboot Type XXIII and the minisub Seeteufel (the tracked project), their real world problems included coastal defense, something transportable overland to the Med, and the case of the minisub, something that could launch itself in absence of facilities.
     
  7. Astrodragon Coffee-seeking Dragon Donor

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    *ahem*
    Hedgehog
     
  8. hipper Just running down the clock Kicked

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    think of the implications of mass type XXI production in 1943 well it take a year for a u boat to come into service, so the XXI comes into use in 1944 too late.

    what the germans need is the XXI to be in service by 1843 to do that they need to be building large numbers in 1942 to do that they would have had to develop the submarine in 1940

    essentially they would have had to put considerable extra resources into U boat production and given up part of their U boat buildup in 1940 to 1943...

    introduction of the Type XXI could have made things easier for the allies The scary prospect is the Germans having a ready to go type XXI in 1940 fortunately versailles had prevented german submarine building i. the 20’s and early 30’s robbing them of time to develop revolutionary submarines rather than evolutionary submarines.
     
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  9. starman Well-Known Member

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    It wasn't that bad. Total u-boats lost from February to April 1943 inclusive was 50. In May 41 were lost from all causes including accidents.

    Depends on how many are available in '43. They may not win the BoA but if they keep tonnage losses in '43 at '42 levels it could slow the allied timetable.
     
  10. starman Well-Known Member

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    They should've halted Type VII production in 1941 and used the resources for the XXI. IMO this wouldn't have been so far fetched; in fact I'm surprised they didn't do it. The loss of the three best aces in March 1941 should've been a resounding wake up call. Allied convoy defenses were getting stronger and they needed a better boat for anticonvoy operations.
     
    Last edited: Nov 10, 2018
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  11. Cryhavoc101 Well-Known Member

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    Correct and well done for spotting the deliberate error....
     
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  12. Astrodragon Coffee-seeking Dragon Donor

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    Some people here keep talking as if doing a revolutionary class of sub is something easy that just requires a bit of work a little earlier.
    It's nothing of the sort.

    Its hard enough improving surface ships and their systems (and this is a lot easier, as you can fit and replace systems reasonably easier).
    Its HARD on a sub, it has a fixed (and very limited volume)

    Worse, a submarine is at the best of times a fatal accident waiting to happen. Rushing development results in them sinking (which they are supposed to do), but not coming back up(which is a problem...).
     
  13. starman Well-Known Member

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    Who said that? Of course it's tough, but doable--look at all the revolutionary changes in the 20th century.
    In his Hitler's U-Boat War Vol. 2, Blair said the XXI had too many defects to have made much difference. But I think that reflected the harsher conditions of 1943-45, when it was being built. If the KM realized, on the basis of their March 1941 setback (as opposed to their May 1943 one), they needed to seriously focus on building a better boat, they might've had it in time to obviate "Black May." (After all, it took just two years from Black May to the first XXI operational missions, and conditions weren't yet as bad from '41 to '43.) Type VII construction should've ceased by mid '41 so resources could be invested in a fleet of XXIs. I think Type IX construction should've been halted too. (The XXI was a big boat by German standards and was capable of fairly long range operations, so they wouldn't need IXs either). Having firms experienced in sub building (like Blom and Voss) build the XXI's, instead of obsolete older boats, might've gone a long way toward obviating some of the XXI's technical issues.
     
  14. thaddeus Well-Known Member

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    they had Dutch snorkel from 1940 but failed to implement it? probably half dozen other plausible evolutionary changes that could be made to Type VII without (major) interruption of the production lines? (not saying they are leaping ahead of Allied countermeasures simply slowing the gains)

    why they didn't attempt smaller u-boat first, especially given need for one in Med, Baltic and Black Seas, and its new production method (which lent itself more to smaller boat)?
     
  15. starman Well-Known Member

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    German crews hated snorts, and they were fooled into thinking METOX revealed their positions.

    They used Type II "ducks" in the Black Sea, and at least once in the NW approaches, see Operation Drumbeat.
     
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  16. eltf177 Well-Known Member

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    This. Unless the bugs are worked out you're going to lose a lot of crews operationally...
     
  17. glamourous glennis Banned

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    We all live, in the yellow kriegsmarine...
     
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  18. thaddeus Well-Known Member

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    half the surviving u-boats had them later, there are problems with any technology and had they been placed in service earlier certainly improvements could have been made (my point)

    yes, understand they transported 6 u-boats to the Black Sea, along with 60 larger ones to the Med, but by 1944 they needed many more, and ones easily transportable overland.

    my post was not a thumbs down vote on Elektroboot technology but opinion on the type that could have actually been built and entered service in some numbers. would add that they tried the Alberich scheme of rubber matting on the Type VII u-boat but later planned on using it on the Type XXIII and Seehund (a realization some of the revolutionary tech easier to apply, in both senses of the word, to smaller boats?)
     
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  19. McPherson McPherson; a guy who needs a shave.

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    It might for one year.

    Here's why.

    1. One of the things about the Battle of the Atlantic that is misunderstood is that the weapon launch platforms, the weapons used, and the target sets are geared fundamentally to several factors.
    a. Signal detection threshold (misinterpreted as range in popular literature.)
    b. Time to target run times or sink-rates with the various weapons the platforms launch platforms employ.
    c. Velocity aggregates (Time over distance) otherwise known as tactical speed of all the objects employed in the three body problem of launch platform, weapon and target.
    d. Angle solution deltas (again time over distance) popularly known either as no-escape zones or probability to hit or probability to kill in popular descriptions. While this involves an aspect function between launch platform and target and also depends on a weapon characteristic, a bomb dropping on a diving submarine versus a torpedo running to a target freighter, the point is that every weapon has a set of parameters where it will meet the target and a set where it will miss.
    2. There is something called tactical speed. Targets, launch platforms and weapon systems have various tactical speeds, but when the aggregate system of systems is tallied up, the sensors employed, the various weapon classes used against freighters and submarines compared, one solves out a unique velocity aggregate mean. It is about 10-12 knots. Outer boundary escape where the tactical speeds exceed the existing launch platforms' ability to track is about 25 + knots. The weapon miss in most cases (freighter) is about 28 knots.

    Hence the allied solution to the type 21 U-boat is ridiculously simple. Build fast freighters. Make the Germans speed up. Not going to happen with a snort boat and not going to happen with German torpedoes. The Allies are inside the technology OODA loop. As for what else?

    If the Allies want to get fancy about it and actually kill U-boats instead of outrun them, then FIDO is going to have to become a 30 knot heavyweight torpedo and their depth charges will need to become larger with about 750 lbs of Composition D with a sink rate of 100 seconds to 300 feet. Complementary to this, the hedgehog mortar will have to become more like the Russian RBU 6000 (easy to do) and ASDIC/SONAR will have to graduate to magnetorestrictive GSF type German multichannel commutator actuated signal chase type sound gear. The Type 21 may be quieter than a Type VII on the battery, but she is twice as noisy on the snort. Read DEAD MEAT. The Germans did not raft their power-train properly. What they know about propellers is... well why do you think FIDO was designed to home in on screws instead of engine noise?

    Hence a year. The US and UK will tighten belts, lose a million more tonnes of shipping and the Russians will be in Berlin on schedule as in the RTL.

    IOW, the Type 21 changes nothing for the Germans. It might mean Russians on the Rhine though as the Allies might have to fort up and go defense in France for a few months. Who knows? Monty might not screw up Caen or Market Garden. The Allied truck shortage might not happen. Bradley might not screw up Falaise or the Bulge and things could still happen as in the RTL.

    What I want the reader to understand, is that the western allies were not stupid. They knew (^^^) about this stuff and were perfectly willing to eat "wonder weapons" for the year it would take to reach Germany, even if it meant more casualties in men and treasure. The Russians were always there as the prime engine of allied victory, so the German doom was inevitable. The real question was where the allied meeting line was going to be.
     
  20. thaddeus Well-Known Member

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    what does variable pitch propeller accomplish? have seen a projected 1 - 2 knots increase in speed (assuming in optimal case?) but for noise? or what is the solution?
     
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