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  1. #11
    Established TDF Member Paulo's Avatar
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    You dont rely on the scrubber, thats why you purge and refill with o2. You manually add o2, not dil, so no need for ADV unless you cannot isolate the ADV and it keeps refilling with DIL as you try to vacuum the old gas out

    You can only do it when not changing depth so on the bottom to get to shot and on deco hangs are the best times.

    Maybe someone will point out my errors or why it doesnt work with the KISS.
    Rememeber anything you read on the internet was probably written by some guy sitting at home in his underpants! Including this !!

    Illegitimi non carborundum

  2. #12
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    Any SCR though either deep with dil via the ADV or shallow via manual o2 add would need a working scrubber surely, which may not be the case if it's wet?

    Or are you talking about a 1:1 ratio essentially oc?

  3. #13
    Established TDF Member Paulo's Avatar
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    Quote Originally Posted by JonG View Post
    Any SCR though either deep with dil via the ADV or shallow via manual o2 add would need a working scrubber surely, which may not be the case if it's wet?

    Or are you talking about a 1:1 ratio essentially oc?
    No 4 - 5 breaths then replace the gas. If you have 100% on 1st breath you get 96% on 2nd, 92% on 3rd 88% on 4th & 84% on 5th breath so worst case scenario, even with zero scrubber you have max 16% CO2 after 5 breaths.

    Replace the gas and start again. I am surprised SCR was not covered in any training. It was on my Mod 1 and we did quite a bit of it on Mod 2
    Rememeber anything you read on the internet was probably written by some guy sitting at home in his underpants! Including this !!

    Illegitimi non carborundum

  4. #14
    Last of the Mohicans gobfish1's Avatar
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    Quote Originally Posted by JonG View Post
    This is with the last stop at 6m:

    DIVE PLAN - BailOut
    Surface interval = 5 day 0 hr 0 min.
    Elevation = 0m
    Conservatism = GF 80/80

    Dec to 60m (4) Diluent 15/55 0.70 SetPoint, 15m/min descent.
    Level 60m 36:00 (40) Diluent 15/55 1.20 SetPoint, 16m ead, 22m end
    Asc to 30m (44) Trimix 18/45 -7m/min ascent.
    Asc to 27m (44) Trimix 18/45 -7m/min ascent.
    Stop at 27m 0:17 (45) Trimix 18/45 0.66 ppO2, 7m ead, 10m end
    Stop at 24m 3:00 (48) Trimix 18/45 0.61 ppO2, 6m ead, 9m end
    Stop at 21m 3:00 (51) Nitrox 50 1.54 ppO2, 10m ead
    Stop at 18m 4:00 (55) Nitrox 50 1.39 ppO2, 8m ead
    Stop at 15m 5:00 (60) Nitrox 50 1.24 ppO2, 6m ead
    Stop at 12m 8:00 (68) Nitrox 50 1.10 ppO2, 4m ead
    Stop at 9m 11:00 (79) Nitrox 50 0.95 ppO2, 2m ead
    Stop at 6m 44:00 (123) Oxygen 1.60 ppO2, 0m ead
    Surface (129) Oxygen -1m/min ascent.

    OTU's this dive: 184
    CNS Total: 115.5%
    Gas density: 4.6g/l

    815.2 ltr Trimix 18/45
    845.3 ltr Nitrox 50
    916.6 ltr Oxygen
    2577.1 ltr OC TOTAL
    john you say your shy on the o2 , in a 3 , you have a shit load of 50% just sit on the 50% till your 3l is not shy .

    no big deal its a bail out plan as long as it works ,
    id be looking to be able to do said bail out on two 7.s and the o2 is just a bones , just cut some time off deco ,

    ps next time its warm take a full 3l sit at 5m and see how long you can make it last .
    nice and slow nice and slow ,

    also i think your planner is taking the piss with that cns number ,
    Last edited by gobfish1; 17-10-2018 at 09:49 PM.
    None diver as of 2018.

  5. #15
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    Quote Originally Posted by gobfish1 View Post

    also i think your planner is taking the piss with that cns number ,
    44min at 6m on O2 - that is pretty much 100% CNS right there.

  6. #16
    Last of the Mohicans gobfish1's Avatar
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    Quote Originally Posted by graham_hk View Post
    44min at 6m on O2 - that is pretty much 100% CNS right there.
    Is it ,

    old money maybe , somewhat less in new money,

    depending on what side of 6m your on the numbers can move from 60 to 80

    just looks a bit over the top for a 60m 40m dive ,

    no matter ,
    Last edited by gobfish1; 18-10-2018 at 12:45 AM.
    None diver as of 2018.

  7. #17
    #keepittea ebt's Avatar
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    Quote Originally Posted by Paulo View Post
    No 4 - 5 breaths then replace the gas. If you have 100% on 1st breath you get 96% on 2nd, 92% on 3rd 88% on 4th & 84% on 5th breath so worst case scenario, even with zero scrubber you have max 16% CO2 after 5 breaths.

    *personally* I wouldnt entertain such a large CO2 content in the loop, thats pushing the edge of cascade failure. SCR is ok with a compromised scrubber, but I'd question its validity with zero scrubber.....

    Unit specific: On a KISS sucking the ADV for SCR is exhausting for any length of time, you'd do better to flip the OC lever to get gas in.

  8. #18
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    I think you'd be surprised at what you can get away with in terms of crap/compromised/used up scrubber at 6/3m.
    One of my early oxy rebreather experiments/fookabouts the scrubber pretty much fell to bits inside and I didn't even notice until I took it to bits afterwards.

    And also, just using it for deco, you have plenty time to keep your attention on whether the unit is doing something stupid and options to go back on OC.

    I wouldn't have it as my *only* plan but it's definitely part of the tool kit.

  9. #19
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    Quote Originally Posted by Paulo View Post
    No 4 - 5 breaths then replace the gas. If you have 100% on 1st breath you get 96% on 2nd, 92% on 3rd 88% on 4th & 84% on 5th breath so worst case scenario, even with zero scrubber you have max 16% CO2 after 5 breaths.

    Replace the gas and start again. I am surprised SCR was not covered in any training. It was on my Mod 1 and we did quite a bit of it on Mod 2
    4% is an absolute mile out
    The loop volume is much bigger than your tidal volume

  10. #20
    Established TDF Member Paulo's Avatar
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    Quote Originally Posted by WFO View Post
    4% is an absolute mile out
    The loop volume is much bigger than your tidal volume
    Very true
    Rememeber anything you read on the internet was probably written by some guy sitting at home in his underpants! Including this !!

    Illegitimi non carborundum


 
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