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  1. #21
    Gone diving back later Vanny's Avatar
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    Quote Originally Posted by barnaby_s View Post
    my plan is rebreather or rebreather depending on the dive.

    Keep things simple.
    ftfy

  2. #22
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    Quote Originally Posted by Vanny View Post
    ftfy
    Might use single cylinders on shore dives with a bit of a walk, but otherwise that seems probably

  3. #23
    Gone diving back later Vanny's Avatar
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    Sure I get it. What I find is a typical club weekend might be hard boat, rib or shore depending on group , weather etc. so I tend to look at my kit and just pick up ccr. I much prefer diving that now for whatever.

  4. #24
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    Quote Originally Posted by Woz View Post
    A 232 ally 7 filled with 32% works fine down to 40m for me and the 7 I use for that is looking pleasingly battered. After a few dives you won't really notice it's there. For the course just fill it with air- you will be bailing out a few times so may need fills in between but you shouldn't get into needing stops.
    Bit OT but doesn't a CO2 event increase blood flow to the brain, which then increases the risk of an oxygen toxicity event, ergo PPo2 of bailout requires consideration and ideally would be circa 1.3/1.4?

    Fine if you can get shallow quickly but might not be feasible if your heads in bits and sending a bag up becomes complex under a dark narc, also might have a swim out if OHE.

  5. #25
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    Hypercapnia is nasty forget any idea of open circuit breathing rates. Its not just the gas consumption its the incredible narcosis that stops you acting rationally. Avoidance is far more important than coping with the effects, Personally I would not use anything less than a 7 litre on shallow dives, deeper than 20 meters I would have a 11 liter cylinder. You do have to consider does carrying too much bale out gas stress you to much causing the CO2 hit. Pack your scrubber properly any doubt bin the fill and start again. Dive with a good buddy and always be prepared to sit out the dive if things are not right.

    Graham

  6. #26
    Last of the Mohicans gobfish1's Avatar
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    11L I'd have to be heading in to 75m plus before I'd strap on the pigs.
    If it gets that bad just push the up button forget the breathing rate and cylinder size . It's game over

    That's a lot of cylinder just to head past 20m
    What a kill joy that is . Avoid it rather than cater for it .
    Is this still the Noddy one thread . Or have I missed the plot lol
    Noddy 1 max 30m no deco on the course .

    As others have said
    Some of use did the courses without a side can
    I bailed out 3 or 4 times on my course .
    Used on board 3 s for a dive or two then did the last bail out from inboard 2l not really a problem gas wise.

    So think a 7l should be more then enough for even the worst situation when training . After that if you want to kill your self hunping gas that's not required go forth. Lol as they say .

    There's a shit load of sop you can do to avoid co2 problems with out humping gas that may never be needed.

    Handy tip get the wife in to pegging and give up diving lol least the wife will have some fun
    Last edited by gobfish1; 11-11-2020 at 07:43 PM.
    None diver as of 2018.

  7. #27
    Coastal Member dwhitlow's Avatar
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    Quote Originally Posted by barnaby_s View Post
    My plan is single cylinder or rebreather depending on the dive.

    Keep things simple.
    agreed. for shore diving single tank is nice and for the everything else CCR is usually the best choice.

    Having walked up the Chesil Pebble Mountain with CCR on my back I'll not repeat that when a single tank is adequate for the dive.

  8. #28
    Coastal Member dwhitlow's Avatar
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    Quote Originally Posted by gobfish1 View Post
    11L I'd have to be heading in to 75m plus before I'd strap on the pigs.
    If it gets that bad just push the up button forget the breathing rate and cylinder size . It's game over

    That's a lot of cylinder just to head past 20m
    What a kill joy that is . Avoid it rather than cater for it .
    Is this still the Noddy one thread . Or have I missed the plot lol
    Noddy 1 max 30m no deco on the course .

    As others have said
    Some of use did the courses without a side can
    I bailed out 3 or 4 times on my course .
    Used on board 3 s for a dive or two then did the last bail out from inboard 2l not really a problem gas wise.

    So think a 7l should be more then enough for even the worst situation when training . After that if you want to kill your self hunping gas that's not required go forth. Lol as they say .

    There's a shit load of sop you can do to avoid co2 problems with out humping gas that may never be needed.

    Handy tip get the wife in to pegging and give up diving lol least the wife will have some fun
    Yep, diving is supposed to be fun. CCR is supposed to be liberating. There's nothing fun about taking an ali80, aka 11l, aka a pig, on a 20m dive for whilch an AL40 of 32% is adequate bailout (probably excessive) but is useful for filling the bag to send up scallops.

    An AL80 is a shit object to willingly carry when diving, if other options are available. For mod1 stuff an AL80 it really isn't necessary and an AL40, or an AL7, should suffice.

    The best plan is to take all available steps to avoid needing bailout and have a 'get me home' plan should things go awry. My 'oh shit' plan is to switch to GF 100/110 and stay shallow whilst I have gas.

    I still carry a reasonable selection of suitable gas and, should I ever need it on a serious dive, I hope it will suffice. So far....

    For those who believe in planning their bailout strategy on the worst case CO2 hit I suggest you need a new hobby! I'd suggest origami but maybe extreme paper cuts might be an issue
    Last edited by dwhitlow; 11-11-2020 at 10:50 PM.

  9. #29
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    Quote Originally Posted by barnaby_s View Post
    I know the answer is the one with enough gas, but it is more what are the like to dive.

    I am booking my MOD1 and one of the kit requirements is a bailout cylinder of at least 5l (if I haven't managed to get something by the course I can rent one of the course).

    For a significant period after completing the course I don't see me going going any deeper than 40m, with most dives likely to be shallower than that (apart from anything else I will need to do a trimix diluent course later as I am not currently trimix qualified).

    On a Inspiration what do people find nicer to dive with, an Ali40 or an aluminium 7l?
    I recently was in the same position as you. I went for an ali 7 as it's very similar in physical size but has slightly more gas .

  10. #30
    All hail ZOM Woz's Avatar
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    Quote Originally Posted by JonG View Post
    Bit OT but doesn't a CO2 event increase blood flow to the brain, which then increases the risk of an oxygen toxicity event, ergo PPo2 of bailout requires consideration and ideally would be circa 1.3/1.4?

    Fine if you can get shallow quickly but might not be feasible if your heads in bits and sending a bag up becomes complex under a dark narc, also might have a swim out if OHE.
    Of course. If I'm doing something at 40m where I can't directly ascend then I'll have a different b/o and dil strategy which will, at that depth, involve a squirt of He to defuzz the brain. But for 90% of my dives where I can come straight up, it works fine.
    I also have the option of b/o onto onboard for a few sanity breaths while I come up a bit and sort the offboard out. But would not rely on onboard for anything more than that.
    I tend to use a single cylinder setup for shore dives, shallow stuff, teaching, and RIB diving, occasionally using my twin 7s as they're a nicely balanced set. I use the 7L twinset for teaching twinset and accelerated deco courses. The twin 12's I just use as a bank I haven't dived them in years as they are good for one thing- hard boat diving and if I'm doing that, I'll use the rebreather. My back can't do heavy sets any more
    For me it's about having the skills to dive anything really competently and picking the right kit for the job. There is no one set of kit that does everything perfectly there will always be a compromise. Hence my garage full of various clobber.
    Last edited by Woz; 12-11-2020 at 09:39 AM.
    I have nothing to do with BSAC any more apart from being a muggle member. So anything I write on here is likely to be complete bollocks. Hooray!


 
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