Sheerwater vs VR3 for an EVO 4th cell?

**Gill Envy** · 14th February 2007, 17:05

Quote: (Originally Posted by Ben Field)

when I first got mine it had a fischer connector, something I believe has no place being on or near a diver because its so fragile- fortunately Bruce makes a hardwired version so I'm getting mine "upgraded".

BEN

Ben, thanks for that. I'll take that into consideration.

**Gill Envy** · 14th February 2007, 17:07

Quote: (Originally Posted by PhilSiswick)

If you want a reasonably priced, completely independent (i.e not sharing cells with the Vision electronics) PO2 monitoring only, you should have a look at the rEvoDream. A lot of people are using them on Inspos with 4/5 cell adaptors. A good plus is that they come with a HUD, so you can ignore them until the HUD flashes something up, or you want to cross-check to the Vision displays.

I haven't done it yet, as a BOV came my way and I've spent the money on that for now, but I'm going to fit one of those to my Vision later in the year.

Cheers,

Any links to recommend for looking into this possibility?
g

**Gill Envy** · 14th February 2007, 17:17

[quote=JonnyB;96282][quote=divetheworld;96154]The Shearwater connects in parallel with your existing three to give on-line PO2 and (GF)deco.

Quote:

sorry for the hijack guys...
this is something i have been thinking about doing with my meg, anyone knows if it is possible?

/Jonny

Jonny, any related quistions are welcome. Why rely on the same three cells? why not a fourth? we hear talk of the primary buggering the secondary, but in this case you would be opening up the possiblility of the secondary buggering the primary as well...it seems like the cost and effort for inlining the sheerwater with the exhisting cells would be just a short step and not much extra $$ from a 4th cell...though I concede that hooking up a sheerwater to one cell could be likened to purchasing a BMW and driving it around in first gear...but it's about the same price as a VR3 so a bit of overkill is justified in my book.

and who knows when i get fed up enough and join the even darker side of home builds, it has nice cross over potential!

**PhilSiswick** · 14th February 2007, 17:24

Quote: (Originally Posted by Gill Envy)

Any links to recommend for looking into this possibility?
g

Gill,

There are some threads on here that discuss it.

More details are on revo english

Cheers,

**Gill Envy** · 14th February 2007, 18:04

Quote: (Originally Posted by PhilSiswick)

Gill,

There are some threads on here that discuss it.

More details are on revo english

Cheers,

thanks Phill, had a quick read over the manual. As before,i'mpressed with the slim design and understanding of the merrits of CFO and even curious about the two scrubbers. A little wierded out by the no switches...turning on and off is a matter of knocking on the back of the handset, which from here, with no real experience quell my concern, seems a little risky, though I guess you have two independent displays (that share the same 02 scensors) so your chance accidentily turning them both off is probably nill... but using one as a back up give me some concern.

Was not sure if it was possible to just get one display handset, didn't see anything about using it as an accessory. Don't remember seeing the battery life listed, the Sheerwaters is certainly impressive. The auto on of the Sheerwater seems like a nice feature that I did not see on the rEvo...

Still interested in the comparison, need more info...will search the archives.

JonnyB · 14th February 2007, 18:30

[quote=Gill Envy;96335][quote=JonnyB;96282]

Quote: (Originally Posted by divetheworld)

The Shearwater connects in parallel with your existing three to give on-line PO2 and (GF)deco.

Jonny, any related quistions are welcome. Why rely on the same three cells? why not a fourth? we hear talk of the primary buggering the secondary, but in this case you would be opening up the possiblility of the secondary buggering the primary as well...it seems like the cost and effort for inlining the sheerwater with the exhisting cells would be just a short step and not much extra $$ from a 4th cell...though I concede that hooking up a sheerwater to one cell could be likened to purchasing a BMW and driving it around in first gear...but it's about the same price as a VR3 so a bit of overkill is justified in my book.

and who knows when i get fed up enough and join the even darker side of home builds, it has nice cross over potential!

Hi Gill, the way i think is that.
1. I would rather depend on 3 cells on my backup than 1. Which will be the case of a fourth cell. Another sollution is having 6 cells and 2 independent computer systems. Which is a bit of overkill. I dont have any problems changing cells frequently and i try to verify the validity as good as possible, by recording mV of each cell prior and after any dive. I also track it over time. One other thing is calibreation procedures. I was told that you can fill the loop with pure O2 and drop down to 6m and verify that you get 1.6ppO2 and then continue the dive.
2. As i undertand, on the Meg, there is not really any good way to connect a fourth cell that is not exposed to a high degree of humidity.
3. The only way to my knowledge to connect a fourth cell on the Meg, is by using the adv port on inhalation side, which means i would need to buy a new neoprene counterlung, which is very expensive.

/Jonny

**Gill Envy** · 15th February 2007, 01:52

thanks jonny, a very understandable approach. yeah, 6 cells is overkill for sure... i've decided with the redundancy of the vision in some respects and the potential common failure point that one additiona cell should round out the system enough for my tastes. We'll see...I have time to keep thinking about it before i make the final move...who knows, maybe a Co2 monitor will come out by then.

[quote=JonnyB;96353][quote=Gill Envy;96335]

Quote: (Originally Posted by JonnyB)

Hi Gill, the way i think is that.
1. I would rather depend on 3 cells on my backup than 1. Which will be the case of a fourth cell. Another sollution is having 6 cells and 2 independent computer systems. I dont have any problems changing cells frequently and i try to verify the validity as good as possible, by recording mV of each cell prior and after any dive. I also track it over time. One other thing is calibreation procedures. I was told that you can fill the loop with pure O2 and drop down to 6m and verify that you get 1.6ppO2 and then continue the dive.
2. As i undertand, on the Meg, there is not really any good way to connect a fourth cell that is not exposed to a high degree of water.
3. The only way to my knowledge to connect a fourth cell on the Meg, is by using the adv port on inhalation side, which means i would need to buy a new neoprene counterlung, which is very expensive.

/Jonny

**Gill Envy** · 15th February 2007, 01:59

thank you everyone for your feedback on and off line.

I'm veering toward the sheerwater at this point for the following reasons:
-better match of deco with the vision
-extremely efficient on batteries, which just seems like a sign of a well engineered system.
-Build quality is impressive
-auto on switch
-HUD option
-very intuitive screen layout
-back light does not suck up the battery...can be left on a lot.
-manufacturer is on the way to some of my favorite diving!
-When i graduate to home building it can be my primary

just kidding

Mdemon · 15th February 2007, 10:02

I found, on my Classic, that the 4th cell VR£ didn't track particularly accurately what the Inspo handsets were doing. Not wildly out, but I didn't fancy basing my deco on it. This was using both DeltaP adapters and also mounting the cell in the head with the others. So, I set the VR£ to a fixed setpoint of 1.25 and accept the slightly longer deco as conservatism.

However, the biggest reason for keeping the 4th cell was so that in the event of a bad flood, or total battery failure or total handset failure or handsets locking me out (which happened to a mate), the independent cell would still give me PO2 info. I think this is more valuable than the realtime deco to be honest.

I've got a rEvodream and that is better still. It's redundancy you can actually use as a primary if you wanted to - and it comes with a HUD as well as a handset. Don't worry about the tapping - it is a total PITA and my knuckles are still sore but actually it is very simple and safe. Turn it on. Dive. Turn it off. Battery life is two years IIRC? Varies with backlight usage etc. Very nice redundancy package + HUD, but no realtime deco or O2 control.

The Shearwater seems to be in a different league again. Everyone with one seems delighted with it. And it does what you want. On the downside, you have no redundancy against duff cells and it's more expensive. However, that needs to be weighed up against how often you think you'd need redundant cells and I can't see it being that often. So it comes down to the cost and whether the extra functionality is what you want to pay for IMHO.

**Dave Sutton** · 15th February 2007, 18:15

Quote: (Originally Posted by JonnyB)

Hi Gill, the way i think is that.
1. I would rather depend on 3 cells on my backup than 1. Which will be the case of a fourth cell. Another solution is having 6 cells and 2 independent computer systems. Which is a bit of overkill. I dont have any problems changing cells frequently and i try to verify the validity as good as possible, by recording mV of each cell prior and after any dive. I also track it over time. One other thing is calibreation procedures. I was told that you can fill the loop with pure O2 and drop down to 6m and verify that you get 1.6ppO2 and then continue the dive.
2. As i undertand, on the Meg, there is not really any good way to connect a fourth cell that is not exposed to a high degree of humidity.
3. The only way to my knowledge to connect a fourth cell on the Meg, is by using the adv port on inhalation side, which means i would need to buy a new neoprene counterlung, which is very expensive.
/Jonny

In order :

(1): A 4th cell is *mainly* of value for independant deco calcs with a tertiary responsiblity as a last ditch PP02 monitor used to survive a pod-fry. In the unlikely event that you need the 4th cell for life support maintenance, it means that your main elesctonics are fried, not that its cells are bad per-se. Use of one cell to ascend and deco out is not an issue, it's easy to do and is as reliable as is required in that situation. Bottom line: If it worked before, it'll work now. You can do a dil flush to validate if you are worried.

(2): *All* cells are exposed to 100% humidity in every rebreather as that's the humidity of circulating gas bolus in every rig. Location from this standoint is not critical. Yes, downstream of the scrubber is "better". It's easy to do (see below).

(3): You can add a 4th cell with the greatest of ease into any rig by simply using a "tee" in the inhale hose, and on any OTS counterlung rig by simply adding a P-Connector into the fabic. Adding a P-Connector to a Meg is a piece of cake.

Dave

14th February 2007, 17:05	#11 (permalink)
Gill Envy Shearwater Copis Divers Current Rebreather/s: Other CCR Other Rebreather/s: Evolution Other CCR Join Date: Nov 2005 Location: seattle Posts: 1,347	Re: Sheerwater vs VR3 for an EVO 4th cell? Quote: (Originally Posted by Ben Field) when I first got mine it had a fischer connector, something I believe has no place being on or near a diver because its so fragile- fortunately Bruce makes a hardwired version so I'm getting mine "upgraded". BEN Ben, thanks for that. I'll take that into consideration. __________________ Gill Envy ...Because I wasn't born with gills! ><(°>><(°>><(°>><(°>><(°>><(°>><(°>><(°>
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14th February 2007, 17:07	#12 (permalink)
Gill Envy Shearwater Copis Divers Current Rebreather/s: Other CCR Other Rebreather/s: Evolution Other CCR Join Date: Nov 2005 Location: seattle Posts: 1,347	Re: Sheerwater vs VR3 for an EVO 4th cell? Quote: (Originally Posted by PhilSiswick) If you want a reasonably priced, completely independent (i.e not sharing cells with the Vision electronics) PO2 monitoring only, you should have a look at the rEvoDream. A lot of people are using them on Inspos with 4/5 cell adaptors. A good plus is that they come with a HUD, so you can ignore them until the HUD flashes something up, or you want to cross-check to the Vision displays. I haven't done it yet, as a BOV came my way and I've spent the money on that for now, but I'm going to fit one of those to my Vision later in the year. Cheers, Any links to recommend for looking into this possibility? g __________________ Gill Envy ...Because I wasn't born with gills! ><(°>><(°>><(°>><(°>><(°>><(°>><(°>><(°>
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14th February 2007, 17:17	#13 (permalink)
Gill Envy Shearwater Copis Divers Current Rebreather/s: Other CCR Other Rebreather/s: Evolution Other CCR Join Date: Nov 2005 Location: seattle Posts: 1,347	Re: Sheerwater vs VR3 for an EVO 4th cell? [quote=JonnyB;96282][quote=divetheworld;96154]The Shearwater connects in parallel with your existing three to give on-line PO2 and (GF)deco. Quote: sorry for the hijack guys... this is something i have been thinking about doing with my meg, anyone knows if it is possible? /Jonny Jonny, any related quistions are welcome. Why rely on the same three cells? why not a fourth? we hear talk of the primary buggering the secondary, but in this case you would be opening up the possiblility of the secondary buggering the primary as well...it seems like the cost and effort for inlining the sheerwater with the exhisting cells would be just a short step and not much extra $$ from a 4th cell...though I concede that hooking up a sheerwater to one cell could be likened to purchasing a BMW and driving it around in first gear...but it's about the same price as a VR3 so a bit of overkill is justified in my book. and who knows when i get fed up enough and join the even darker side of home builds, it has nice cross over potential! __________________ Gill Envy ...Because I wasn't born with gills! ><(°>><(°>><(°>><(°>><(°>><(°>><(°>><(°>
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14th February 2007, 17:24	#14 (permalink)
PhilSiswick Phil Siswick, Tango Current Rebreather/s: Evolution Other Rebreather/s: Inspiration Vision Join Date: Apr 2006 Location: Oxford, UK Posts: 1,092	Re: Sheerwater vs VR3 for an EVO 4th cell? Quote: (Originally Posted by Gill Envy) Any links to recommend for looking into this possibility? g Gill, There are some threads on here that discuss it. More details are on revo english Cheers, __________________ Phil (WSKD 0001) I have always felt that the dive I am on is not nearly important as the dives I plan to be on the rest of my life. Tom Rose, 2007 The person who gets the farthest is generally the one who is willing to do and dare. The sure thing boat never gets far from shore. Charles A. Lindbergh www.hugsac.org.uk
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14th February 2007, 18:04	#15 (permalink)
Gill Envy Shearwater Copis Divers Current Rebreather/s: Other CCR Other Rebreather/s: Evolution Other CCR Join Date: Nov 2005 Location: seattle Posts: 1,347	Re: Sheerwater vs VR3 for an EVO 4th cell? Quote: (Originally Posted by PhilSiswick) Gill, There are some threads on here that discuss it. More details are on revo english Cheers, thanks Phill, had a quick read over the manual. As before,i'mpressed with the slim design and understanding of the merrits of CFO and even curious about the two scrubbers. A little wierded out by the no switches...turning on and off is a matter of knocking on the back of the handset, which from here, with no real experience quell my concern, seems a little risky, though I guess you have two independent displays (that share the same 02 scensors) so your chance accidentily turning them both off is probably nill... but using one as a back up give me some concern. Was not sure if it was possible to just get one display handset, didn't see anything about using it as an accessory. Don't remember seeing the battery life listed, the Sheerwaters is certainly impressive. The auto on of the Sheerwater seems like a nice feature that I did not see on the rEvo... Still interested in the comparison, need more info...will search the archives. __________________ Gill Envy ...Because I wasn't born with gills! ><(°>><(°>><(°>><(°>><(°>><(°>><(°>><(°>
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14th February 2007, 18:30	#16 (permalink)
JonnyB Johnny The Hatch Current Rebreather/s: MK 15.X Titan Other CCR Other SCR Home Build Other Rebreather/s: Not Bought Yet Inspiration Classic Megalodon Sport Kiss Classic Kiss Other CCR Other SCR Home Build Join Date: Jan 2005 Location: Sweden (Stockholm)/Cyprus(Ayia Napa) Posts: 991	Re: Sheerwater vs VR3 for an EVO 4th cell? [quote=Gill Envy;96335][quote=JonnyB;96282] Quote: (Originally Posted by divetheworld) The Shearwater connects in parallel with your existing three to give on-line PO2 and (GF)deco. Jonny, any related quistions are welcome. Why rely on the same three cells? why not a fourth? we hear talk of the primary buggering the secondary, but in this case you would be opening up the possiblility of the secondary buggering the primary as well...it seems like the cost and effort for inlining the sheerwater with the exhisting cells would be just a short step and not much extra $$ from a 4th cell...though I concede that hooking up a sheerwater to one cell could be likened to purchasing a BMW and driving it around in first gear...but it's about the same price as a VR3 so a bit of overkill is justified in my book. and who knows when i get fed up enough and join the even darker side of home builds, it has nice cross over potential! Hi Gill, the way i think is that. 1. I would rather depend on 3 cells on my backup than 1. Which will be the case of a fourth cell. Another sollution is having 6 cells and 2 independent computer systems. Which is a bit of overkill. I dont have any problems changing cells frequently and i try to verify the validity as good as possible, by recording mV of each cell prior and after any dive. I also track it over time. One other thing is calibreation procedures. I was told that you can fill the loop with pure O2 and drop down to 6m and verify that you get 1.6ppO2 and then continue the dive. 2. As i undertand, on the Meg, there is not really any good way to connect a fourth cell that is not exposed to a high degree of humidity. 3. The only way to my knowledge to connect a fourth cell on the Meg, is by using the adv port on inhalation side, which means i would need to buy a new neoprene counterlung, which is very expensive. /Jonny __________________ A quote from Crazyduck - In remembering our own Rob Davies. "Outbound flight 777 heavy you are cleared for flight Due west into that warm red Texas sunset You have angels on your wings and divers memories on your six." Rest In Peace http://www.divetekcyprus.com http://www.diveccr.com Last edited by JonnyB : 15th February 2007 at 07:26. Reason: corrections to reasoning
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15th February 2007, 01:52	#17 (permalink)
Gill Envy Shearwater Copis Divers Current Rebreather/s: Other CCR Other Rebreather/s: Evolution Other CCR Join Date: Nov 2005 Location: seattle Posts: 1,347	Re: Sheerwater vs VR3 for an EVO 4th cell? thanks jonny, a very understandable approach. yeah, 6 cells is overkill for sure... i've decided with the redundancy of the vision in some respects and the potential common failure point that one additiona cell should round out the system enough for my tastes. We'll see...I have time to keep thinking about it before i make the final move...who knows, maybe a Co2 monitor will come out by then. [quote=JonnyB;96353][quote=Gill Envy;96335] Quote: (Originally Posted by JonnyB) Hi Gill, the way i think is that. 1. I would rather depend on 3 cells on my backup than 1. Which will be the case of a fourth cell. Another sollution is having 6 cells and 2 independent computer systems. I dont have any problems changing cells frequently and i try to verify the validity as good as possible, by recording mV of each cell prior and after any dive. I also track it over time. One other thing is calibreation procedures. I was told that you can fill the loop with pure O2 and drop down to 6m and verify that you get 1.6ppO2 and then continue the dive. 2. As i undertand, on the Meg, there is not really any good way to connect a fourth cell that is not exposed to a high degree of water. 3. The only way to my knowledge to connect a fourth cell on the Meg, is by using the adv port on inhalation side, which means i would need to buy a new neoprene counterlung, which is very expensive. /Jonny __________________ Gill Envy ...Because I wasn't born with gills! ><(°>><(°>><(°>><(°>><(°>><(°>><(°>><(°>
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15th February 2007, 01:59	#18 (permalink)
Gill Envy Shearwater Copis Divers Current Rebreather/s: Other CCR Other Rebreather/s: Evolution Other CCR Join Date: Nov 2005 Location: seattle Posts: 1,347	Re: Sheerwater vs VR3 for an EVO 4th cell? thank you everyone for your feedback on and off line. I'm veering toward the sheerwater at this point for the following reasons: -better match of deco with the vision -extremely efficient on batteries, which just seems like a sign of a well engineered system. -Build quality is impressive -auto on switch -HUD option -very intuitive screen layout -back light does not suck up the battery...can be left on a lot. -manufacturer is on the way to some of my favorite diving! -When i graduate to home building it can be my primary just kidding __________________ Gill Envy ...Because I wasn't born with gills! ><(°>><(°>><(°>><(°>><(°>><(°>><(°>><(°>
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15th February 2007, 10:02	#19 (permalink)
Mdemon SiegeEngine II Current Rebreather/s: Inspiration Classic Home Build Other Rebreather/s: Inspiration Classic Home Build Join Date: Feb 2007 Location: SWUK Posts: 1,946	Re: Sheerwater vs VR3 for an EVO 4th cell? I found, on my Classic, that the 4th cell VR£ didn't track particularly accurately what the Inspo handsets were doing. Not wildly out, but I didn't fancy basing my deco on it. This was using both DeltaP adapters and also mounting the cell in the head with the others. So, I set the VR£ to a fixed setpoint of 1.25 and accept the slightly longer deco as conservatism. However, the biggest reason for keeping the 4th cell was so that in the event of a bad flood, or total battery failure or total handset failure or handsets locking me out (which happened to a mate), the independent cell would still give me PO2 info. I think this is more valuable than the realtime deco to be honest. I've got a rEvodream and that is better still. It's redundancy you can actually use as a primary if you wanted to - and it comes with a HUD as well as a handset. Don't worry about the tapping - it is a total PITA and my knuckles are still sore but actually it is very simple and safe. Turn it on. Dive. Turn it off. Battery life is two years IIRC? Varies with backlight usage etc. Very nice redundancy package + HUD, but no realtime deco or O2 control. The Shearwater seems to be in a different league again. Everyone with one seems delighted with it. And it does what you want. On the downside, you have no redundancy against duff cells and it's more expensive. However, that needs to be weighed up against how often you think you'd need redundant cells and I can't see it being that often. So it comes down to the cost and whether the extra functionality is what you want to pay for IMHO. __________________ www.southwestmafia.com "small minds talk about people, Average Minds Talk About Events, GREAT MINDS TALK ABOUT IDEAS!" The WRONG Attitude will get you killed. "Once the agenda-monkeys and perfect-worlders have moved on, perhaps we can do some diving?" Last edited by Mdemon : 15th February 2007 at 10:04.
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15th February 2007, 18:15	#20 (permalink)
Dave Sutton Diveshop of Horrors Current Rebreather/s: Sport Kiss MK 15.X rEvo Other CCR Azimuth Home Build Other Rebreather/s: Evolution Megalodon rEvo Other CCR Azimuth Home Build Join Date: Jun 2006 Location: Narragansett, Rhode Island and Hackettstown, New Jersey Posts: 2,907	Re: Sheerwater vs VR3 for an EVO 4th cell? Quote: (Originally Posted by JonnyB) Hi Gill, the way i think is that. 1. I would rather depend on 3 cells on my backup than 1. Which will be the case of a fourth cell. Another solution is having 6 cells and 2 independent computer systems. Which is a bit of overkill. I dont have any problems changing cells frequently and i try to verify the validity as good as possible, by recording mV of each cell prior and after any dive. I also track it over time. One other thing is calibreation procedures. I was told that you can fill the loop with pure O2 and drop down to 6m and verify that you get 1.6ppO2 and then continue the dive. 2. As i undertand, on the Meg, there is not really any good way to connect a fourth cell that is not exposed to a high degree of humidity. 3. The only way to my knowledge to connect a fourth cell on the Meg, is by using the adv port on inhalation side, which means i would need to buy a new neoprene counterlung, which is very expensive. /Jonny In order : (1): A 4th cell is mainly of value for independant deco calcs with a tertiary responsiblity as a last ditch PP02 monitor used to survive a pod-fry. In the unlikely event that you need the 4th cell for life support maintenance, it means that your main elesctonics are fried, not that its cells are bad per-se. Use of one cell to ascend and deco out is not an issue, it's easy to do and is as reliable as is required in that situation. Bottom line: If it worked before, it'll work now. You can do a dil flush to validate if you are worried. (2): All cells are exposed to 100% humidity in every rebreather as that's the humidity of circulating gas bolus in every rig. Location from this standoint is not critical. Yes, downstream of the scrubber is "better". It's easy to do (see below). (3): You can add a 4th cell with the greatest of ease into any rig by simply using a "tee" in the inhale hose, and on any OTS counterlung rig by simply adding a P-Connector into the fabic. Adding a P-Connector to a Meg is a piece of cake. Dave __________________ "Silent Diving with No Bubbles and No Politics".... www.nobubblediving.com
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