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Thread: Sentenil VS JJ ccr

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    RBW Member Hk101gr is on a distinguished road Hk101gr is on a distinguished road Hk101gr's Avatar
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    Re: Sentenil VS JJ ccr

    Since all ccrs are great when they work I would look at what happens when they break down.
    If it happens in the water you need redundancy to get you out or you can bailout anyway and be on the safe side. All rebreathers have some form of redundancy built in anyway.
    More commonly though you will catch something on the predive so a machine that uses common parts can be fixed faster and easier on the field. Nothing can be worse than going on a great trip and not being able to dive your rebreather.
    Also vr really dropped the ball when they stopped supporting their flagship units... What if they do the same to the sentinel in a couple of years?

  2. #32
    So many CCR So little etc Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase's Avatar
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    Re: Sentenil VS JJ ccr

    Quote Originally Posted by ChrisBrown  View Original Post
    Let's get my original question answered first;)


    Sent from my iPhone using Tapatalk


    I thaught i did,

    To be more specific

    I love Sheerwater because after years of Inspo classics failing and Hammer heads failing and being on boats when Sentinals fail, Visions fail and Megs fail

    I finaly found a ECCR controler that just seems to work and keep on working.

    Add to that the 99GF function which is gods gift to bailout planning and the Smithers code three LED HUD and I find it an all round great bit of kit.

    If we look arround at other manufacturors out there many have decided to run on a Sheerwater Platform which is a great endorsement.


    Dont get me wrong the first attempt at a Shearwater Meg in 2005 went horably wrong. But since then its been all good


    ATB

    Mark

  3. #33
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    Re: Sentenil VS JJ ccr

    Quote Originally Posted by Mark Chase  View Original Post
    I thaught i did,

    To be more specific

    I love Sheerwater because after years of Inspo classics failing and Hammer heads failing and being on boats when Sentinals fail, Visions fail and Megs fail

    I finaly found a ECCR controler that just seems to work and keep on working.

    Add to that the 99GF function which is gods gift to bailout planning and the Smithers code three LED HUD and I find it an all round great bit of kit.

    If we look arround at other manufacturors out there many have decided to run on a Sheerwater Platform which is a great endorsement.


    Dont get me wrong the first attempt at a Shearwater Meg in 2005 went horably wrong. But since then its been all good


    ATB

    Mark
    No, I meant from Dwane. He made the statement about the shearwater controller.

    2 out of 4 had problems for me. However, that might be rEvos fault not shearwater. Potting and wiring issues. Overall a stellar system and a fantastic computer obviously

    Downsides - controlling PO2 on ascent vs some other controllers. How many variations on solenoid opening duration do you get? I think on the vision its anything from 1/6th a second to infinity. Gives a smooth ascent.

    Still, for you lads that manually maintain above set point, its irrelevant.

  4. #34
    RBW Member Hk101gr is on a distinguished road Hk101gr is on a distinguished road Hk101gr's Avatar
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    Re: Sentenil VS JJ ccr

    Quote Originally Posted by ChrisBrown  View Original Post
    No, I meant from Dwane. He made the statement about the shearwater controller.

    2 out of 4 had problems for me. However, that might be rEvos fault not shearwater. Potting and wiring issues. Overall a stellar system and a fantastic computer obviously

    Downsides - controlling PO2 on ascent vs some other controllers. How many variations on solenoid opening duration do you get? I think on the vision its anything from 1/6th a second to infinity. Gives a smooth ascent.

    Still, for you lads that manually maintain above set point, its irrelevant.
    The vision has the solenoid very close to the cells which is more important then the solenoid firing intervals for tight PO2 control.

  5. #35
    RBW Member Packhorse is a glorious beacon of light Packhorse is a glorious beacon of light Packhorse is a glorious beacon of light Packhorse is a glorious beacon of light Packhorse is a glorious beacon of light Packhorse is a glorious beacon of light Packhorse is a glorious beacon of light Packhorse is a glorious beacon of light Packhorse is a glorious beacon of light Packhorse is a glorious beacon of light Packhorse is a glorious beacon of light Packhorse's Avatar
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    Re: Sentenil VS JJ ccr

    Quote Originally Posted by ChrisBrown  View Original Post

    .... I think on the vision its anything from 1/6th a second to infinity. Gives a smooth ascent.
    Would that not result in a lot of O2 wastage?

  6. #36
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    Re: Sentenil VS JJ ccr

    Quote Originally Posted by Hk101gr  View Original Post
    The vision has the solenoid very close to the cells which is more important then the solenoid firing intervals for tight PO2 control.
    Not sure were talking about the same thing. The vision intelligently injects anything from tiny amounts of 02 to constantly open on a rapid ascent, covering everything you do dynamically in the water. Some units Ive tried seem to have 3 maybe 4 speeds and its clunky in comparison. Unit overshoots or undershoots. That was my point.

    Quote Originally Posted by Packhorse  View Original Post
    Would that not result in a lot of O2 wastage?
    Quite the opposite I find, as theres less overshooting and opening for long intervals when less will do.

    Is this a huge deal? NO. But I thought Id give my opinion as someone was raving about how great the shearwater is at p02 control

  7. #37
    RBW Member Hk101gr is on a distinguished road Hk101gr is on a distinguished road Hk101gr's Avatar
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    Re: Sentenil VS JJ ccr

    Quote Originally Posted by ChrisBrown  View Original Post
    Not sure were talking about the same thing. The vision intelligently injects anything from tiny amounts of 02 to constantly open on a rapid ascent, covering everything you do dynamically in the water. Some units Ive tried seem to have 3 maybe 4 speeds and its clunky in comparison. Unit overshoots or undershoots. That was my point.
    I believe we are, on the vision the cells are close to the solenoid so the controller gets an immediate feedback from the po2 hence has tighter control. The variable injection times also help.
    On units like the meg o2 is injected way before the cells so the controller overshoots more easily. The same happens with the revo I believe.

    I never got the fuss about how tight setpoint is kept.
    What's an acceptable range?Is it important for deco?
    Don't think so. It's one of those details people get obsessed about for no apparent benefit.

  8. #38
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    Re: Sentenil VS JJ ccr

    Quote Originally Posted by Hk101gr  View Original Post
    I believe we are, on the vision the cells are close to the solenoid so the controller gets an immediate feedback from the po2 hence has tighter control. The variable injection times also help.
    On units like the meg o2 is injected way before the cells so the controller overshoots more easily. The same happens with the revo I believe.

    I never got the fuss about how tight setpoint is kept.
    What's an acceptable range?Is it important for deco?
    Don't think so. It's one of those details people get obsessed about for no apparent benefit.
    What makes you conclude that the position is more effective than the action of the solenoid? I would argue that the action has the greatest effect. The position of the solenoid won't help you on a rapid ascent, but the ability to constantly inject 02 will.

    As for benefit - It depends on your dive. If you manually maintain 1.3 and end up averaging 1.2ish theres hardly any different, however on a 100m dive it could be 30 minutes extra run time;) I remember seeing profiles from a Britannic dive where the eccr guys got out quicker which was a big deal as the seas were really rough.

  9. #39
    RBW Member Hk101gr is on a distinguished road Hk101gr is on a distinguished road Hk101gr's Avatar
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    Re: Sentenil VS JJ ccr

    Both have an important effect, but for control to be tight the cells should get a reading of what the solenoid is doing sooner than later because in the meantime another fire input to the solenoid might be given raising the po2 even more.


    I never said manually maintaining po2. I said that "average" po2 would be the same ,say 1.2 but it will fluctuate more on some units than others.

  10. #40
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    Re: Sentenil VS JJ ccr

    Quote Originally Posted by Hk101gr  View Original Post
    Both have an important effect, but for control to be tight the cells should get a reading of what the solenoid is doing sooner than later because in the meantime another fire input to the solenoid might be given raising the po2 even more.


    I never said manually maintaining po2. I said that "average" po2 would be the same ,say 1.2 but it will fluctuate more on some units than others.
    The manual control was an example of how po2 variance can affect deco on a deep dive. OK then, machine A maintains an average of 1.2, unit B maintains an average nearer to 1.3. That would be big enough to warrant consideration at 100m.

    Again - the position of the solenoid does not affect PO2 control as much as the solenoids ability to inject oxygen. The vision has a lot of control on the solenoid, which was my original point.

    Not a huge issue agreed. Im just countering the claim about the Shearwater somehow being considered 'better' at po2 management

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