Hello and welcome to our community! Is this your first visit?
Register
Page 1 of 2 12 LastLast
Results 1 to 10 of 11
  1. #1
    TDF Member
    Join Date
    Jul 2013
    Location
    Mid Scotland
    Posts
    126
    Likes (Given)
    4
    Likes (Received)
    29

    open circuit v rebreather

    A couple of great documentaries on TV recently, icebergs and the search for Franklins ships, with diving in Arctic waters featured. It was significant that all the diving in these sub zero waters was being carried out on open circuit, why? when rebreathers supply slighly warmed gas to the diver. Whatever happened to the rebreather revolution?

  2. #2
    TDF Member
    Join Date
    Sep 2017
    Location
    Chippenham
    Posts
    199
    Likes (Given)
    10
    Likes (Received)
    52
    Didn't see them so not sure of depths, but if they were on mix then the gas would be significantly warmer. No idea on why all OC most of the commercial stuff I see all the support are on CCR and presenter is oc as their main job is presenting and learning a ccr profeciently is longer more committed process.

    If general film crew on expedition usually oc, if divers are exploring and then film ccr.

  3. #3
    Established TDF Member Chrisch's Avatar
    Join Date
    Jan 2013
    Location
    Poole
    Posts
    7,555
    Likes (Given)
    712
    Likes (Received)
    3261
    Maybe the divers are not CCR certified? Lots of us aren't.

  4. #4
    Established TDF Member OutOfTest's Avatar
    Join Date
    Oct 2013
    Location
    Sheffield
    Posts
    1,112
    Likes (Given)
    50
    Likes (Received)
    349
    I havenít used CCR in temps much colder than -20 so this is just postulating.

    Could there be some consideration for moisture on sensors freezing after a dive and killing sensors?

    Maybe thereís something to do with length of expedition and shipping large quantities of O2 compared to a compressor?

    Hasnít sorb got a temperature limit on it?

    Batteries in cold conditions donít work great.




    Sent from my iPhone using Tapatalk

  5. #5
    Established TDF Member
    Join Date
    Jan 2013
    Location
    East Midlands
    Posts
    2,921
    Likes (Given)
    841
    Likes (Received)
    1142
    Blog Entries
    2
    Rebreathers need a lot of TLC when it gets cold. If the scrubber gets too cold, the sorb will freeze (or rather the moisture in it will) and then it doesn't work. Your breath can thaw it for many UK style applications, where we consider 0C to be cold, but in extreme conditions, that might not work so well. OC stuff however, is a lot more robust in that respect.

  6. #6
    TDF Member
    Join Date
    Jul 2013
    Location
    Mid Scotland
    Posts
    126
    Likes (Given)
    4
    Likes (Received)
    29
    Quote Originally Posted by Chrisch View Post
    Maybe the divers are not CCR certified? Lots of us aren't.
    Doug Allen and Andy Torbet? You don't get much more experienced than them. I would imagine they are certified for CCR. I would think the freezing issue has more to do with it. If you havn't already viewed the shows then they are certainly worth seeing. Diving into the drain hole of a glacier lake takes an awfull lot of bottle!

  7. #7
    Underwater Creative BARDO's Avatar
    Join Date
    Dec 2012
    Location
    South Coast
    Posts
    515
    Likes (Given)
    257
    Likes (Received)
    384
    Many of these decisions are based on two simple factors...

    1. Logistics
    2. Appropriate tool for the job

    A rebreather isn't necessarily the right choice in every environment/location. Sometimes the simplicity and reliability of OC gear outweighs the flexibility and efficiency of a rebreather.
    Follow my work on Facebook... www.bardocreative.co.uk
    View my online photo library... www.bardophotographic.com
    "None are more hopelessly enslaved than those who falsely believe they are free" - JW Goethe

  8. #8
    TDF Member
    Join Date
    Jan 2013
    Posts
    171
    Likes (Given)
    0
    Likes (Received)
    15
    I believe the Franklin wreck was in 11m, ccr would be a bit of an overkill.

  9. #9
    Old but keen Mark Chase's Avatar
    Join Date
    Dec 2012
    Location
    Kent UK
    Posts
    3,864
    Likes (Given)
    830
    Likes (Received)
    2456
    Quote Originally Posted by thistlediver View Post
    A couple of great documentaries on TV recently, icebergs and the search for Franklins ships, with diving in Arctic waters featured. It was significant that all the diving in these sub zero waters was being carried out on open circuit, why? when rebreathers supply slighly warmed gas to the diver. Whatever happened to the rebreather revolution?
    Main reason would be HSE clearance insurance & commercial diver training requirement of some countires


    Second likely reason is they simply were not trained in CCR let alone trained to satisfie the commercial aspect of the dive



    I base this on a offer I had some years ago where I was asked to be a deep support diver for a NG series on deep wrecks.

    It fell through as they needed to use commercial divers and the cost apparently went biblical.

  10. #10
    Last of the Mohicans gobfish1's Avatar
    Join Date
    Jan 2013
    Location
    the grassy knoll
    Posts
    3,423
    Likes (Given)
    3915
    Likes (Received)
    2159
    Quote Originally Posted by BcDiver View Post
    I believe the Franklin wreck was in 11m, ccr would be a bit of an overkill.
    full Elf and safety m8 , Commercial Diving set up sop,s for them ,
    None diver as of 2018.


 
Page 1 of 2 12 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •