Question about WWII German U-boat bow planes

Discussion in 'Boat Design' started by Gannet, Oct 22, 2009.

  1. Gannet
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    Gannet Junior Member

    wardd Great discovery. I going to review it now and probably be back with more comments.

    bntii - Have not been to the Torsk yet, but now that I am retired it will give me something to do. I have been to the Submarine Muesem in Pearl Harbor. Also, The Wolf Pack Book how big is the downloaded pdf?

    I have been going through all my Submarine Books.

    The following are applicable excerpts on diving planes and bow planes from Friedman, Norman; Submarine Design and Development; Conway Maritime; London; 1984:
    • Diving planes perform three very different functions; diving, surfacing, and depth and trim control. The latter must be quite precise at or near periscope depth.
    • At greater depths, it is more important for maneuvering, so that the rate of changing depth is more important than the ability to maintain a particular depth.
    • Bow planes were initially added to permit submarines to dive on an even keel, although that has not been the standard practice for many decades.
    • Bow planes located underwater (when the submarine was fully surfaced) would be effective as soon as they were inclined, and so would (in theory) make for fast submergence, but they were also a source of resistance, making for reduced surface speed. Planes above the waterline would not slow a submarine, but they would not take effect until it reached the awash condition; i.e., until some considerable flooding had occurred.
    • Bow planes were also notoriously subject to damage when coming alongside or docking. One compromise was folding planes employed by many navies. However, it was argued that the extra mechanism increase their chance of failure.
     
  2. bntii
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    bntii Senior Member

    Good morning Gannet,

    I see you are in Baltimore, MD. I am just down the road in DC. I had a chance to board the Torsk some years back.

    I don't know how large the download is. I reviewed the text in the on-line browser & the download is limited to members. Do you have a copy of Rossler's book?

    Yeah- that site wardd posted is remarkable.
    I spent some time going over the accounts & period photos.

    [​IMG]

    Some happy faces among these German kids captured after their sub was destroyed. No surprise given how rare it was to have survived.
     
    Last edited: Oct 27, 2009
  3. Gannet
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    Gannet Junior Member

    Yes I am right up I-95 from you. Lived here all my life except when I was in the Marine Corp and when I was Marine Engineer on a Merchant.

    I am member of Scibd, when I tried to download the pdf it was up to 30 Meg when I got a runtime error.

    I remember reading that 4 out of 5 German U-boat sailors perish during WWII.

    I don't have Rossler's book.

    I have been reviewing the design study and the statement they make in it "complete entity present little of interest" does not sit well with me. I hope they were not "jumping to conclusions." But as wardd mentions it does call what I've been calling "fixed fins," "Plane guards for bow planes."

    Also apex 1, I notice that at the site wardd provided http://www.uboatarchive.net/index.html
    they are looking for translators. IMHO you would be ideal

    Another thought I was having is that having the bow planes always underwater even when on the surface provided any hydrodynamic lift like hydrofoils to reduce wetted area.

    I really enjoy this discussion it is nautical, technical, and historical:)
     
  4. wardd
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    wardd Senior Member

  5. Submarine Tom

    Submarine Tom Previous Member

    I toured the HMCS VICTORIA in dry dock last week.

    www.naval-technology.com/projects/ssk_victoria/

    She has retractable (not folding) bow planes. They are surpisingly small

    and not used very often. They would be submerged while surfaced.

    Tom
     
  6. apex1

    apex1 Guest

    Me too.
     
  7. Gannet
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    Gannet Junior Member

    Wardd still going through the design study you found and also the other index which has an article on the "The Working Environment for German Submarine Design in WWII" You are like a hound dog finding these great sites!

    One thing I noticed in the design study is that on the Type IXC-40 the bow planes are rigged at a 7 degree rise (design was for a 5 degree rise) and because it is submerged while the submarine is running on the surface would provide lift such that it would reduced wetted area. I am thinking that the reduction in skin friction drag maybe significant enough to offset the drag associated with the bow plane being submerged.

    Another thing I noticed in the report is that all the control surfaces: rudders, stern planes, and bow planes were electrically actuated.

    Also there is mentioned "Further with respect to rudders, the vertical center of area is relatively higher on the vessel than it is in current U.S. Naval practice, thereby reducing the tendency for the vessel to take a list when turning." I am also thinking that having the bow planes permanently rigged also reduces this listing during turns

    Submarine Tom
    From Friedman, Norman; Submarine Design and Development; Conway Maritime; London; 1984; p124 he states:
    Apex1 The only people I give flowers to are the wife or dead people. I was just bringing it to your attention.

    Thanks again
     
    Last edited: Oct 26, 2009
  8. apex1

    apex1 Guest

    You ruined my day. :mad:
    I was so happy I´ve given the right explanation and to receive a bunch of pansies.
    And then that...............
     
  9. Knut Sand
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    Knut Sand Senior Member

  10. wardd
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    wardd Senior Member

    people often get caught up in the weapon itself as though it acted alone

    case in point was the panther and tiger tanks, yes they were big and mean but that brought on a whole set of problems such as getting them to the battlefield and being so expensive and labor intensive that few were built

    same as for subs the Germans had the wrong equipment for the second half of the war for the area of combat and the enemy's capabilities where as the american subs succeeded against the Japanese because the had the right mix of capabilities for their environment
     
  11. apex1

    apex1 Guest

    The Tiger Tank was too heavy and overly complicated to be a good tank. Thats true, but the Panther was far better. The Tiger was designed by Ferdinand Porsche btw.

    The Type VII boats were almost a perfect weapon (far better than any allied sub) but the German Admirality did not understand some problems.

    1- The tactic was deadly:
    the so named "wolf- pack" tactic required a radio signal sent by the first boat in contact with a target (mainly convoy), to bring more boats in contact. These signals were easily located by British and US forces and the "surprising moment" was gone gone. Quite often this first boat was attacked and scuttled.
    But there was no possible solution, due to the fact that the "Luftwaffe" had no (or no sufficient) control over the most important area in the North Atlantic.

    2- The lack of understanding the abilities of Radar.
    Though the technology was used by themselves (and in the years 1937 `til 39 the German "Radar" was even better than the British), the German Military did not understand that it could be possible to "see" a target as small as a periscope! They did not get it until the war was over.
    So, many boats have been far away from being invisible.

    3- The German Enigma code was cracked in Bletchley Park after the British forces had brought up a damaged U-boat and salvaged the Enigma machine. From that day on, almost all German Navy operations were well known by the Allied forces.

    4- Last: the sheer amount of Allied battleships was by far too much to make most of the attacks "successful", from 1943 on.

    The situation in the Pacific was a completely different one.

    Regards
    Richard
     
  12. wardd
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    wardd Senior Member

    i see the weapon as part of a system, if any part of the system is deficient then you are not going to get the best out of the weapon.

    radar as a point, no matter how good the sub was with out good radar and radar detection they went to the bottom despite the quality.

    the ability of the allies to pinpoint the location of uboat radio transmissions no matter how short the burst was is another point that negated the quality of the build

    failure of the high command to take corrective action in the face of mounting loses negated build quality

    the type xxi while being innovative wasn't really technology that couldn't have been introduced earlier, but the attitude that the war wouldn't last that long came back to bite Germany in the ***.

    all these and probably more canceled out the quality of the build

    the Sherman tank was inferior in its weapon and armor and had mistakes made during the design phase , in that it was thought a high velocity gun would wear out too fast, they didnt grasp the fact that the tank wouldnt last that long in combat anyway, but the big advantage of the sherman was automotive quality (it was highly reliable) it was cheap and many thousands were made and shermans could be replaced from the supply chain, while late in the war they were waiting for tigers being repaired to put back into combat, they couldnt make enough
     
  13. Gannet
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    Gannet Junior Member



    From http://www.navy.mil/navydata/cno/n87/history/fullhist.html
    I am thinking the main reason for this disparity in casulties ratios is because the Germans U-boats were up against American, British, and Canadian Allied Forces whereas, the United States in the Pacific were only against the Japanese. Also, the Pacific battlespace was immensely larger than the Atlantic battlespace.
     
    Last edited: Oct 27, 2009
  14. wardd
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    wardd Senior Member

    the best weapon for the environment isn't always the best weapon technically possible

    and contrary to what some believe the Japanese military wasn't on par with the then modern western militarys , they were just better prepared at the beginning of the war
     

  15. apex1

    apex1 Guest

    Do´nt forget there have been just very few allied submarines in the Atlantic, operating as excessive (in terms of sea days) as the Germans.
    Then, the war was half won when the US entered!
    Other than the German U boot bases, the US and Canadian were not under aircraft attack!
    And there has been no tonnage battle (convoy´s) in the Pacific.

    That makes some statistics become quite clearer.

    And of course, wardd, weapon is a system, not just the "gun" and the system on the German side had one major fault from 1936 on, Hitler!!! He did not leave his generals decide, he was the superior leader in his idiotic sight, and every single one of his decisions was wrong.
    One can say in all seriousness, that Hitler alone has lost that war. (which was´nt to win anyway after the hughe economy of the US became part of it)
    That started in Dunkerque and ended in a storm of fear, blood, steel and violence in Dresden and Ostpreussen 1945.................

    The Sherman tank btw was really scrap, a lousy car. If there would have been a serious opponent and not one already conquered, I doubt one would have survived. The Russian T34 was a real enemy for the German tanks, due to his extreme robustness.

    Sorry for the aside, there was not really any relation to the "fins".:rolleyes:

    Regards
    Richard
     
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