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Thread: Are mCCR's safer than eCCR's?

  1. #161
    All IMVHO obviously... Ben Field has a reputation beyond repute Ben Field has a reputation beyond repute Ben Field has a reputation beyond repute Ben Field has a reputation beyond repute Ben Field has a reputation beyond repute Ben Field has a reputation beyond repute Ben Field has a reputation beyond repute Ben Field has a reputation beyond repute Ben Field has a reputation beyond repute Ben Field has a reputation beyond repute Ben Field has a reputation beyond repute Ben Field's Avatar
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    Re: Are mCCR's safer than eCCR's?

    Quote Originally Posted by Capt Morgan  View Original Post
    Mark and Ben, could you tell me if you use a capped or un-capped first stage ?
    Normal compensated reg for me, the fixed IP is redundant when you can modulate the flow surely?

  2. #162
    RBW Member jlovold is a jewel in the rough jlovold is a jewel in the rough jlovold is a jewel in the rough jlovold is a jewel in the rough jlovold is a jewel in the rough jlovold is a jewel in the rough jlovold is a jewel in the rough jlovold's Avatar
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    Re: Are mCCR's safer than eCCR's?

    Quote Originally Posted by Ben Field  View Original Post
    To answer the questions- it is a Chris Kennedy Valve from Oz, about £230 including shipping, IMO cheap given the performance and quality. Prices obviously highly dependant on your location, exchange rate and shipping.



    No offence jlovold but it would appear you are a mistaken believer in the Cult of Constant PPO2?


    You do not need to fiddle with a needle valve.


    Yes you might adjust it on deck doing a pre-breath and then again as you approach your dive depth and perhaps a nudge up or down while on the bottom but IME less than I would top up the loop on a leaky valve. On ascent I only adjust the PPO2 at stop depths, in between I let it fall- the PPO2 is almost meaningless for the tiny amount of times in-between stops. Ascending above 6mtrs I ignore it entirely and thumb O2 in occasionally if I think it's necessary, its so simple it defies a lengthy explanation.

    If you try to maintain an exact set point on any MCCR you are (IMVHO) missing the point, the flexibility of the loop and manual control is that you can let it rise and fall knowing the average is the important factor. If you are running tables then some adherence is necessary but most people dive in-line deco so as long as the loop is something breathable you're good. Usually it will drift around in the 1.15-1.35 region without any intervention, on the Needle valve you can give it and nudge every 10min and keep it tighter but why bother?


    An important thing to know with the Needle valve is that you can wind it shut and the bypass will still function- this is useful to know if you wanted it on your ECCR as a backup/hybrid, more importantly you can pressurise your unit fully and run all your checks prior to kit up without wasting O2, something stock MCCR's can do if not equipped to avoid it. You all know you shouldn't be turning on your O2 while strapped to your unit for obvious reasons
    Guilty as charged!

    I like keeping my PO2 stable, and after just a few dives it was really simple to do.

    Also, it keeps your buoyancy spot on, which is one of the reasons I am not a fan of eCCRs.

    Also, when your buoyancy is spot on, it gives you a good idea about how your PO2 is behaving....

  3. #163
    All IMVHO obviously... Ben Field has a reputation beyond repute Ben Field has a reputation beyond repute Ben Field has a reputation beyond repute Ben Field has a reputation beyond repute Ben Field has a reputation beyond repute Ben Field has a reputation beyond repute Ben Field has a reputation beyond repute Ben Field has a reputation beyond repute Ben Field has a reputation beyond repute Ben Field has a reputation beyond repute Ben Field has a reputation beyond repute Ben Field's Avatar
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    Re: Are mCCR's safer than eCCR's?

    Quote Originally Posted by jlovold  View Original Post
    Guilty as charged!

    I like keeping my PO2 stable, and after just a few dives it was really simple to do.

    Also, it keeps your buoyancy spot on, which is one of the reasons I am not a fan of eCCRs.

    Also, when your buoyancy is spot on, it gives you a good idea about how your PO2 is behaving....
    Yes, Yes and Yes.

    I agree although I am happy to tolerate a stable drift up or down safe in the knowledge I don't need to react for 10+minutes.

    Reacting, seeking perfection when it is unnecessary is fiddling and fiddling as we all know leads to issues, issues can become problems and no one likes those

    The same as with people who strip their units entirely between dives and are constantly cleaning and re-lubing always seem to be chasing leaks and gremlins, those who constantly tweak PPO2 on MCCR seem to have the odd spike or dip they are unhappy with. Me- I'm happy to allow it to wander around the right area for simplicities sake.

  4. #164
    RBW Member Capt Morgan is an unknown quantity at this point Capt Morgan's Avatar
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    Re: Are mCCR's safer than eCCR's?

    Quote Originally Posted by Ben Field  View Original Post
    Normal compensated reg for me, the fixed IP is redundant when you can modulate the flow surely?
    That was my thinking but I was confused when it was mentioned that
    it took very little adjustment.

  5. #165
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    Re: Are mCCR's safer than eCCR's?

    I now use the Chris Kennedy needle valve on my Kiss Classic.
    None compensating DS4. (Less needle adjustments)
    11 bar at surface. (100m is anyhow too deep for a 71 year young diver)
    Needle shut = 0.5L at surface (own adjustment - now similar to a KISS std valve).

    The valve is connected to the LEFT side of the head (the unused inlet).
    The oxygen goes directly into the sensor chamber on the inhale side.

    +
    very easy to spike sensors to 2+ anytime during the dive while holding breath for
    3-5 seconds. As soon as I breathe out and wait 3-5 seconds, the PPO2 is down to normal and that little oxygen cloud is diluted in the inhale CL.
    +
    very easy to pre dive check the sensors for 0,98


    -
    When manually adding oxygen I carefully use the button and only when breathing out.


    I use the needle extensively. Except when spiking the sensors, I hardly never use the manual button. It is much easier than I thought it should be to maintain PPO2 using the needle.

    One of the reasons why I bought the needle valve was the possibility to adjust to a high flow before jumping in and when ending the dive (from 6 m). This is really adding security!
    Before I used 2 KISS valves in parallell to accomplish that when ascending and in shallow water.

    Some guys have doubts about thick gloves/needle valves.
    I use thick thumb gloves without any troubles.

    Regards
    Sven Becker

  6. #166
    Photographer & Journalist John Liddiard has a spectacular aura about John Liddiard has a spectacular aura about John Liddiard has a spectacular aura about John Liddiard has a spectacular aura about John Liddiard has a spectacular aura about John Liddiard's Avatar
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    Re: Are mCCR's safer than eCCR's?

    I used to dive a Swagelock needle valve on an MCCR hacked Drager. I used it with a regular Poseidon first stage.

    To start a dive I would flush with O2 and open it about 1 turn, inject dil on the way down, then close the needle nearly all the way when I reached dive depth. To ascend I would then open it 1+ turns and that would compensate for expansion on the way up. At longer stops I would tighten it up to just a crack again. When I first started using it I was surprised at how stable the PO2 was.

    EDIT: With thick gloves the original knob was a bit fiddly and fell off when the grub screw rusted. I machined a 1cm delrin knob with a stainless dome-screw that also served as an index mark. No problems feeling where it was with gloves on.
    Last edited by John Liddiard; 14th September 2016 at 20:31.

  7. #167
    CCR Cave Explorer jcr is an unknown quantity at this point jcr's Avatar
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    Re: Are mCCR's safer than eCCR's?

    +1 on the ease and simplicity of a needle valve although I dive it with a blocked uncompensated 1st stage. I keep it closed until I get on the loop and then set it during my prebreathe. After that, only the occasional fine tuning to adjust for different metabolic needs during the dive, i.e., swimming, scootering, deco. It's as effortless as diving an orifice with none of the limitations.

    I use a stronger spring adjusted to 200 psi IP, which gives me a practical depth limit of 400 fsw. If needed, I can adjust the IP as high as 290 psi with the stronger spring, which gives a practical depth limit of 600 fsw.

    I dove an eCCR for a while and did some long exploration dives with it but it always made me a little nervous (or maybe not nervous enough) as I felt like it bred complacency. I feel much more in tune with the unit with the needle valve.

  8. #168
    All IMVHO obviously... Ben Field has a reputation beyond repute Ben Field has a reputation beyond repute Ben Field has a reputation beyond repute Ben Field has a reputation beyond repute Ben Field has a reputation beyond repute Ben Field has a reputation beyond repute Ben Field has a reputation beyond repute Ben Field has a reputation beyond repute Ben Field has a reputation beyond repute Ben Field has a reputation beyond repute Ben Field has a reputation beyond repute Ben Field's Avatar
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    Re: Are mCCR's safer than eCCR's?

    Quote Originally Posted by Capt Morgan  View Original Post
    That was my thinking but I was confused when it was mentioned that
    it took very little adjustment.
    Compensated regs only compensate for depth so if you transition you adjust? (check- ears, wing, loop and suit, continue to dive..)

    The biggest pressure change is in the depths we don't commonly dive 0-10mtr, below that its pretty linear.

    Maybe I'll try it with a blocked 1st stage for comparison... since that's what all the cool kids are doing?

  9. #169
    RBW Member Capt Morgan is an unknown quantity at this point Capt Morgan's Avatar
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    Re: Are mCCR's safer than eCCR's?

    Quote Originally Posted by Ben Field  View Original Post
    Compensated regs only compensate for depth so if you transition you adjust? (check- ears, wing, loop and suit, continue to dive..)

    The biggest pressure change is in the depths we don't commonly dive 0-10mtr, below that its pretty linear.

    Maybe I'll try it with a blocked 1st stage for comparison... since that's what all the cool kids are doing?

    I know different people use them differently so was just wondering what
    way you used it. I've been thinking of fitting one for almost as long as I've
    had my unit but have never bitten the bullet.
    Last thing I'm worried about is being a cool kid

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