Inspiration 4th Cell options

[Pierre Farrugia]

Thanks Uri,

Can you please keep us posted on here when your web site is running.

Thanks

Pierre

[Andy Phillips]

OK,

I've just dismantled my new (secondhand) unit. It came with a VR3 4th cell adapter.

I've gots some thoughts, it's mounted down-stream from the other three cells, surely the most accurate place you could measure the gas you are actually breathing would be at the mouth piece so logically the nearer you get to that point the more accurate the measurement would be. So, in my somewhat humble opinion, I am not going to worry about the fact that it tracks a bit differently (assuming it is going to). In fact I would expect it to measure down a bit from the other cells, in which case it would be increasing my deco comitment which I believe would make the dive a bit safer in these terms.

I would be very interested to hear from anyone who has got one and what has happened to them.

Andrew

[beanie]

Originally Posted by imported_andyp

OK,

I've just dismantled my new (secondhand) unit. It came with a VR3 4th cell adapter.

I've gots some thoughts, it's mounted down-stream from the other three cells, surely the most accurate place you could measure the gas you are actually breathing would be at the mouth piece so logically the nearer you get to that point the more accurate the measurement would be. So, in my somewhat humble opinion, I am not going to worry about the fact that it tracks a bit differently (assuming it is going to). In fact I would expect it to measure down a bit from the other cells, in which case it would be increasing my deco comitment which I believe would make the dive a bit safer in these terms.

I would be very interested to hear from anyone who has got one and what has happened to them.

Andrew

er when you've done the course and get on the insp list search the archive (set aside about six months for this subject) some people were saying that the vr3 was differnt from the ybod and saying the ybod electrics were wrong and all kinds of stuff lots of opinions
i know that a few people just didn't bother with the link or did and took it off again

[Drmike]

Originally Posted by imported_andyp

I would be very interested to hear from anyone who has got one and what has happened to them.

Hi Andrew,

Quite a few people have them. They are all sat safely in a drawer somewhere


Seriously though, theres been a lot of BS written about these 4th cells. Best bet is try it on your unit for yourself and see how you get on. IMO I would have one just as a back up in case of electronics failure - but I wouldnt worry about running deco off it as the setpoint controller is very accurate.

My advice is do a VERY long and thorough O2 flush before you calibrate the VR3 (some found it better to do that off the unit in a plastic back - I don't know if I agree)

If you read any BS about 'the VR3 ppo2 is right and the YBOD controller is wrong' its easy to dispel (and I do this on every dive anyway) just do a good O2 flush at 6m or 3m and make sure you just get up to 1.6 or 1.3 respectively on your handsets then see what your 4th cell is giving you.

[ My own new unit and a buddies unit came from the factory with duff sensors (temp compensation board gave cell drift) - due to this buddy took an O2 tox hit so I always do a 6m or a 3m check at the end of every dive to track my cell life.]

Good luck

Cheers
Mike

[Rob Evans]

I use a VR3 and for a long time looked closely at the opinions drifting about the various fora and concluded the 4th cell wasn't for me.
The only major advantage that I could see it gave me was accurate PO2 tracking if I had to go SCR. The disadvantages as outlined, particularly the tracking issue, made up my mind just to spend a bit more creative time generating realistic bailout tables for that mode of operation. I now have a set of tables for most depths and most dives which I can just cart around in my suit pocket.
Saved a shedload of money and don't have to put up with the grief of wondering which is correct in terms of PO2 for normal CCR use - the handsets or the pooter.
Should it eventually prove the VR3 tracks truer than the handsets (which I doubt for a number of reasons) there's likely only to have been a minute or so discrepancy in terms of deco requirements at the end of the sort of dives I do (25-85m). Given that I now pad out (or add) deep stops according to V-Planner for the deeper stuff, I reckon that evens things out.
Not bent yet, anyway <<frantically touching wood>>