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Argonaut Kraken HP seat failure...?

Discussion in 'Vintage Equipment Diving' started by Fibonacci, Oct 13, 2018.

  1. Fibonacci

    Fibonacci Manta Ray

    # of Dives: 500 - 999
    Location: Melbourne, Australia
    535
    440
    63
    New thread split off the Kraken hose loop flooding issue for clarity...

    A quick summary:
    I had a failure of the HP seat in my near new Kraken on the morning of Day 3 of a 9 day PNG dive trip.
    Up till then it had performed perfectly and caused a great deal of interest from the other divers.
    I was loving the start of the whole DH experience, so it was very annoying to have it fail before I got the chance to fully explore DH diving.
    On my return home I returned the Kraken and the DSV to the US at Bryan's request... no local service available in Australia.
    He serviced the Kraken and replaced the HP seat for free which was good but the returned parts showed a very strange wear pattern where the HP Volcano Orifice had engraved the HP Seat so far off centre it hit the inner metal support for the pin, venting HP air through to the loop.
    Kraken HP seat failure detail.jpg
    There are some white shadows/darker discoloration on the seat face but the damaged indent is where the material failed. You can see the indent is considerably off centre to the pin aperture, and appears to have been sheared at an angle.
    I have pulled apart quite a few Conshelf XIV and Cousteau SEA's and never seen this sort of very off-centre wear pattern. Bryan was at a loss to explain why this would occur, which makes me feel uneasy about it re-occurring.

    Hopefully Luis will copy his content here from the other thread so both issues can be discussed separately.
     
  2. Luis H

    Luis H Instructor, Scuba

    # of Dives: I'm a Fish!
    Location: Maine
    2,836
    964
    113
    I don’t know what does the first stage seat has to do with the exhaust hose, or why did you posted that in this thread. In any case, I am actually seeing two different things on the pictures of that seat. The indentation from the volcano and a crack on the surface of the seat material. It is just a picture, so please let me know If what I see from the picture is not correct.

    I am pointing to the indentation from the volcano orifice with a red arrow and to the crack with a green arrow.

    I also added a red circle on top of the indentation from the volcano orifice. You may notice that the crack doesn’t for a good circle. It doesn’t even has a smooth curve.

    This crack is definitely a defect or a malfunction. Again I do not know where Bryan gets his seats other that they are being made by a Scuba parts manufacturer/ supplier. I have seen bad seats before.


    dive-at-cozumel-with-argonaut-x2-jpg.484037.jpg



    The red circle is covering volcano orifice indentation:

    dive-at-cozumel-with-argonaut-5-jpg.484038.jpg
     
  3. Luis H

    Luis H Instructor, Scuba

    # of Dives: I'm a Fish!
    Location: Maine
    2,836
    964
    113

    That is not what I am seeing in that picture. I will explain.

    The volcano orifice can be considered to be a perfect circle.

    I highlighted with a red arrow on the left what is obviously the indentation from the volcano orifice. Then a laid a circle to match that indentation. You can see on the right where that indentation has a matching mark.

    On the right, the volcano orifice indentation is not as clear, because there is that material fracture (that I pointed with the green arrow).

    I look at my “perfect circle” laying on top of the volcano orifice mark, and it look fairly concentric to the seat. That is not a problem.


    This fracture is a defect. It falls into the category of infant mortality. I started servicing regulator (at a dive shop “professionally”) close to 50 years ago and I have seen a few of this from several manufacturers. IMHO, I place into the category of "$hit happens". Infant mortality is the reason no one would buy anything from a manufactures that doesn’t have at least an initial warranty (of some reasonable period of time).
    As an Industrial Design Engineer, I am sure you are familiar with the term infant mortality.

    It is a real shame that it happened when it happened to you! I feel really sorry that it happened at that moment. But, if you are familiar with Murphy’s law (and I am sure you are, all engineers should), you will know that failures rarely happen when it is convenient.

    Bryan told me that he has only had two seat failures from this manufactures. One is yours and the other belonged to a good friend of ours from the Philippines. Again following Murphy’s law, the two failures couldn’t happen to a neighbor of Bryan or maybe one of the Argonauts here in Maine that I could have helped. Bryan could help anyone in the US with overnight shipping, but of course it had to happen to someone on the other side of the world...


    I know most people don’t have a spare Argonaut or a even a spare back-up regulator. I do and I always carry both an Argonaut and a spare single hose regulator. They have both been used by many friends (sometimes they are instant friends having an issue at the dive site).

    I also always carry spare parts on a trip (I organize many dive trips with groups of friends). I am a strong believer that if you have the spare part, you will not need it (the other part of Murphy’s law).


    OK enough philosophy this early in the morning…

    Good luck and good dives…
     
    couv and Sam Miller III like this.
  4. Fibonacci

    Fibonacci Manta Ray

    # of Dives: 500 - 999
    Location: Melbourne, Australia
    535
    440
    63
    Ah yes Mr Murphy is my constant companion at work :D

    This being my first LOB in a very remote area with a DH reg I did indeed carry a spare single hose reg set... Old Faithfull, a Conshelf XIV with Sea Hornet Command Air second stages and a SPG. So I was able to switch to this backup system seamlessly... and not use the usual ancient backup reg set fished out of the bilge that is the norm on most LOB's!

    I also carried a comprehensive array of spares <except> spare hose clamps, which I needed early on before I realised the HP seat was spiking IP. 200psi air was being delivered to the DSV mouthpiece then leaking past the corrugated hose Cobra clamps then finally venting out the octo!

    So yes, hopefully this HP issue is just one of those rare infant mortality failures and the Kraken is as reliable as all the others are reported to be.

    All the best in diving...
     

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