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rEvolutionary HPDW'ing
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Discussion Starter · #1 ·
Ok so in the absence of doing any real diving this weekend I have been putting a bit of thought in to redundancy. I have all the ingredients to make a decent off-board o2 kit for my revo, the problem is I just can't see me ever using it. I'm leaning towards the view that it adds complexity to a rig and just isn't necessary.

I guess if I were diving alpininst then carrying it would be a no brainer, but I carry bailout on all dives and run team bailout on big dives.

Do you make provisions for off-board o2? Do you carry it on all dives or is there a cut off point?
 

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Supporting Sea Shepherd
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So really you were bored and decided to do a bit of fettling. Nowt wrong wi that. I do think if you were considering going alpinist then its a good move but if your talking team bailout then your always going to need bailout tins so really it's carrying it for the sake of it.
 

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rEvolutionary HPDW'ing
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Discussion Starter · #3 ·
Nothing wrong with a bit of fettling, but its something I have been toying with for a bit. I had an off board kit on the Sentinel and never used it for o2 the DIL side got quite a bit of use though.
 

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Team HPDW - 10/90 for the Boys
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Just do what I did, give in to your kit tart tendencies and buy the triple MAV from Paul (pick it up in person this weekend :D)
Then you can plumb your 80% stage in if you manage to run out of 02
OTOH if you need the lead to sink then it's not going to hurt having an 02 bottle with a whip is it?
 

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rEvolutionary HPDW'ing
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Discussion Starter · #5 ·
Just do what I did, give in to your kit tart tendencies and buy the triple MAV from Paul (pick it up in person this weekend :D)
Then you can plumb your 80% stage in if you manage to run out of 02
OTOH if you need the lead to sink then it's not going to hurt having an 02 bottle with a whip is it?
But what do you use it for. ;)
 

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rEvolutionary HPDW'ing
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Discussion Starter · #7 ·
Personally I can't see a point where I would need an extra 02 bottle but people might argue that it's more useful than 3kg of lead.
So... "I bought the triple MAV because it looks cool" :D
 

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Jesus don't want me for a sunbeam
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Personally I can't see a point where I would need an extra 02 bottle but people might argue that it's more useful than 3kg of lead.
That's part of the reason I carry it. My unit is quite floaty, I need something to sink it so it might as well be useful. For shallower stuff I've got 30min of deco gas OC worst case. I usually just dive with the offboard 3 of O2, another of air for my suit and BOV plus onboard trimix and O2 and that's it, nice and self contained and I don't have to dick about with side slung gas for 35-45'ish metre dives. It's also handy for using hypoxic gases as it's good for plugging into the BOV at 6m instead of having deep gas connected. On longer deco if I'm feeling lazy then I've plugged the offboard O2 into the ADV at 6m.
 

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Driving my truck with my high-heels on...
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Andy if you want to see a triple mav in the flesh to tempt yourself then I can show you mine (oh err missus) when we meet in a dodgy layby on Thursday :)
 

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rEvolutionary HPDW'ing
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Discussion Starter · #11 ·
That's part of the reason I carry it. My unit is quite floaty, I need something to sink it so it might as well be useful. For shallower stuff I've got 30min of deco gas OC worst case. I usually just dive with the offboard 3 of O2, another of air for my suit and BOV plus onboard trimix and O2 and that's it, nice and self contained and I don't have to dick about with side slung gas for 35-45'ish metre dives. It's also handy for using hypoxic gases as it's good for plugging into the BOV at 6m instead of having deep gas connected. On longer deco if I'm feeling lazy then I've plugged the offboard O2 into the ADV at 6m.
I thought of taking it and simply just sticking a reg on it for use at 6m, as you say its got to be worth 20-25mins of deco.

Do people take and use off-board as a matter of course? Has it ever got anyone out of the shit?

I can see how some people use two o2 sources on hybrid units like the revo one ballanced first stage and one unballanced, for the orifice and one for the solenoid. To be honest though when I do dives deep enough to require a ballanced first stage I'll just run the unit full eccr and blank off the oriifce.
 

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rEvolutionary HPDW'ing
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Discussion Starter · #12 ·
Andy if you want to see a triple mav in the flesh to tempt yourself then I can show you mine (oh err missus) when we meet in a dodgy layby on Thursday :)
I've done three or four dives on a unit with the triple MAV, its a nice addition to the rEvo but I really like the simplicity of the unit and can't see any point adding potential faliures that arent needed. When I finally sort out a scooter later this year then I'll see how dificult the rEvo is to scooter with Although when im resting my PPo2 goes up by 0.02 or so every 8-10 minutes so I'll probably not need it until I give in to my inner kit tart. :D
 

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currently offshore, please leave a message
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Andy,

With Boris No 1 I used to take an off board O2 bottle, 2L, the revo runs 3l doesn't it?

A few reasons why....no particular order

I had the kit to do it

I figured that if I was at 45m and for some reason I had a problem with the 2nd stage within the unit I had full redundancy and sooner that than go to OC.

It balanced out the fact I had a stage and an argon bottle on the other side

In mines if I was going up and down due to following the topography I could just plug it in and draw of both bottles due to the increased gas usage

And I am sure there were others.....

I never used it in open water in less than 30m except for testing and in mines but I liked it and will probably do the same again when Boris 2 arrives.

Like others have said it's more useful than 3kg of lead

G
 

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rEvolutionary HPDW'ing
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Discussion Starter · #14 ·
With Boris No 1 I used to take an off board O2 bottle, 2L, the revo runs 3l doesn't it?

A few reasons why....no particular order

I had the kit to do it

I figured that if I was at 45m and for some reason I had a problem with the 2nd stage within the unit I had full redundancy and sooner that than go to OC.

It balanced out the fact I had a stage and an argon bottle on the other side

In mines if I was going up and down due to following the topography I could just plug it in and draw of both bottles due to the increased gas usage

And I am sure there were others.....

I never used it in open water in less than 30m except for testing and in mines but I liked it and will probably do the same again when Boris 2 arrives.

Like others have said it's more useful than 3kg of lead

G
Yes the rEvo does take 3ltrs but can take 2ltrs also plus you can attach cylinders to either side of pretty much any size. I can sink it with out any lead so that's not really the issue, it's offsetting the extra complexity against the risk. And based on this logic if it becomes part of your rig and it does fail either pre dive or whilst diving do you abort just as you would if you lost bailout?

I put quite a few hours on a sentinel which I believe has the same off board arrangement as the boris (???). And I only ever used off board for dil, where do you mount your off boar gas on your boris?
 

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RE: if it failed before the dive - not that it ever happened, I would probably not worry too much and would just disconnect it and take the cylinder off the pony clamp and dive anyway, it is after all a nice to have not a must have.

I mounted it via pony mount onto the o2 cylinder of my Boris and ran the off-board hose under my right arm and into the block, the system is exactly the same as the Sentinel system I think but I don't know for sure. Maybe you can tell me if the gas connection goes into the solenoid/ADV like it does on the Boris or is it manual add only when connected?

I don't know anything about the off-board system on the rEvo so it may not be as practical to do this on one of those as it is on a Boris/Sentinel

Like you I didn't need any lead whatsoever to get me to sink, I have a 28 inch waist which helps!! so if i took it off on one dive and put it on on another it really made no difference to me.

G
 

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I dive a rEvo II and I have an offboard 2l of O2 clipped to the side of the unit. I have a MAV on the front with a quick connect. I don't connect the O2 bottle unless I need it.

If you have a failure of the onboard o2 then it is pretty handy to have a spare. I have actually experienced a failure of my onboard first stage and lost almost all of my gas. For me carrying a spare is a no-brainer. It doesn't add any additional failure points as it is not connected until needed.

Most of the guys I dive with do the same.

Mike
 

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I carry a 1L bottle of O2 mounted on the backplate on the other side to my suit gas. I can plug it in and run manually if I lost my onboard O2. I don't use it OC. I know a couple of people who have had to bail out due to loss of O2 due to a 1st stage or hose failure. Its enough for 60-90 mins deco before I'd have to bail.
 

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rEvolutionary HPDW'ing
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Discussion Starter · #18 ·
RE: if it failed before the dive - not that it ever happened, I would probably not worry too much and would just disconnect it and take the cylinder off the pony clamp and dive anyway, it is after all a nice to have not a must have.

I mounted it via pony mount onto the o2 cylinder of my Boris and ran the off-board hose under my right arm and into the block, the system is exactly the same as the Sentinel system I think but I don't know for sure. Maybe you can tell me if the gas connection goes into the solenoid/ADV like it does on the Boris or is it manual add only when connected?

I don't know anything about the off-board system on the rEvo so it may not be as practical to do this on one of those as it is on a Boris/Sentinel

Like you I didn't need any lead whatsoever to get me to sink, I have a 28 inch waist which helps!! so if i took it off on one dive and put it on on another it really made no difference to me.
The Sentinel has exactly the same off board system as this i.e. the gas weather it be O2 or DIL goes through the automation, so loss of either would not rely on a manual addition of o2 every 20 secconds. The rEvo MAV is not this sophisticated but you dont really need it to be as there is a CMF so o2 addition is not required as frequently.

If you have a failure of the onboard o2 then it is pretty handy to have a spare. I have actually experienced a failure of my onboard first stage and lost almost all of my gas. For me carrying a spare is a no-brainer. It doesn't add any additional failure points as it is not connected until needed.
But the MAV its self is an additional faliure point is it not? Like I said in a pervious post does adding a mav (with the extra faliure points) just to allow you to get extra gas in to the loop out weigh the risk of not taking the extra o2? I believe adding an extra set of buttons multiplies the risks of unwanted gas passing in to the loop. Not necessarily the off board o2 but the connected inboard gas o2/dil.
 

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Mr potty mouth: Sweeping generalist...............
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I also have all of the kit but tbh I would only consider it as an option when going past 70M where bail out gas starts to be a problem shallow and having an extra 30 minutes of deco would help.
However, what stops me most, is the odds of a first stage going pop v's loop loss or some other point of major issue after taking on a long deco obligation? From my experience it tends to be early in the dive not later.

For me, I check my IP's as part of every kit up along with an inspection for salt ingress etc so although you need lead it's not like a 1:1 ratio between surface weight and in water weight for the benefit you get.

I have however looked at this set up for dive travel where I can't get boosted O2 and want to run on decanted gas from the right stage.

PL
 

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But the MAV its self is an additional faliure point is it not? Like I said in a pervious post does adding a mav (with the extra faliure points) just to allow you to get extra gas in to the loop out weigh the risk of not taking the extra o2? I believe adding an extra set of buttons multiplies the risks of unwanted gas passing in to the loop. Not necessarily the off board o2 but the connected inboard gas o2/dil.
I guess the MAV is an additional failure point. You don't need to connect the MAV to onboard O2 if you are worried about it. For me it is pretty easy to turn off the cylinder if there is some sort of button malfunction. I like having the front-mounted button when scootering, it is a bit handier. you are adding some potential leak points but for me the advantage of being able to add an additional source of o2 is worth it.

Mike
 
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