Bent on the VR3?

[nigelH]

Originally Posted by beanie

hows the colour screen?

Tell you when it gets back. It only went last week.
This is Delta-P remember.

[Mark Chase]

Originally Posted by Andy M

After reading all this thread I'm really going off the VR3...

I was going to buy one at the dive show for CCR air dill and then later this year trimix dill, but from what people are saying it is a useless piece of junk.

Maybe I would be better staying with my viper, and setting it to use the bottom mix nitrox in the loop at ppO2 1.2, and then use tables for trimix dill. Yeah I wont get the deco benefit of the richer mix in the loop at shallower depths but so what...

What can you say to convince me I should buy a VR3 and abandon the Viper??

Andy

I did this for a while but the VR3 is much much better IF you want computer driven deco. Sunnto's just gett pissed off when you muck about with your ascent profiles. In the end I was just bending it all the time, as I just knew it was giving me rubbish. Like VR3 has cleared but Suunto telling me I still have 45mins at 6

If not then its expensive so take your pick of the cheaper options. The Buhlmann model with deep stops that’s on the VR3 is old fashioned IMHO and I tweak it with intermediate stops and slow ascents but I thing the new VPM model due out in the summer may well be the answer to the criticisms of its profiles.

ATB

Mark Chase

[Mark Chase]

=johnv]Seeing as this thread is about getting bent on the VR3, I feel it's worth pointing out three things:

3. go for either one or the other, using bullhman and "ignoring the helium" is a recipie for disaster, you cannot pick the best bits from deco systems and not get bent. subscribe fully to either, understand the implications of what you are doing, but don't just "ignore gas X" by telling the VR3 you have only a nitrigenn mix when on trimix or you will end up in the pot sooner rather than later.

John

Thats not quite right as the VR3 isnt straight Bhulman its just hulman bassed deco. Also ignoring the He in the mix or telling the computer you have less than you actualy have is quite common practice and for a lot of divers it works. I have to say it has worked for me but only on the 6 dives I actualy managed to test it on so not much of an information base I am afraid

Also, back on topic, I have noticed mv VR3 schedules get me to 6m what seems like quickly, but I often pad the middle section and 6m to surface section manually. works for me

This is prety much what I do.

ATb

Mark CHase

[Fraser]

Originally Posted by FathomsDown

I won't mention the DIR diver I dived with last year who ignored his deco schedule as my VR3 and 80% stage got me out of the water faster than his Decoplanner and 50% stage plan did then.

I think that you/he may define DIR diver a little differently than I do then

Originally Posted by DrMike

I didnt know this. Thats interesting. Can I ask why?

It's a rule of thumb mainly to play safe, increasing time in the water much over that would add unnecessary complexity and risk.

Fraser.

[johnv]

Originally Posted by Mark Chase

Thats not quite right as the VR3 isnt straight Bhulman its just hulman bassed deco.

agreed, but the principal of not mixing models stands. There is something I'm missing here, this thread is about the VR3 seeming to have shorter stops in thte mid range, yet you suggest ignoring helium which requires those mid range stops to be longer. this does not add up.

I'd be genuinely interested in example trimix dives & deco that you or others you reliably know to have done where you told a VR3 you were on an N2 / O2 mix for deco but really used trimix. The only person I know who did this on a dive of any significance ended up in a chamber.

I would expect that there is probably slack to get it wrong & be ok on short decos, it's the dives with say 90min+ deco I'm interested in, or multiple shorter decompression dives one after the other.

regards,
John

[Mark Chase]

Originally Posted by johnv

I'd be genuinely interested in example trimix dives & deco that you or others you reliably know to have done where you told a VR3 you were on an N2 / O2 mix for deco but really used trimix. The only person I know who did this on a dive of any significance ended up in a chamber.

regards,
John

Remember we are only talking about the 32/35 deco gas here using somthing like 18/45 back gas. The VR3 knows about the back gas but dosent know about the He in the deco gas.

ATB

Mark Chase

[johnv]

Originally Posted by Mark Chase

Remember we are only talking about the 32/35 deco gas here using somthing like 18/45 back gas. The VR3 knows about the back gas but dosent know about the He in the deco gas.

I hadn't forgotten this, and would still be interested in the examples as requested above.

what sort of lengths of deco are you doing this on?

John

[Drmike]

Originally Posted by Andy M

What can you say to convince me I should buy a VR3 and abandon the Vyper?

In my opinion its a very good safety tool. If it all turns pear shape and you end up having to change dils or go OC or go semiclosed in part or all the dive or deco, or in anyway have to unexpectedly switch gasses, its a real safety advantage to have the VR3 (with the push of a button) to recalculate your deco in real time.

I am happy to follow mine if doing multilevel wreck dives. I do a very slow ascent to first indicated deep stop but otherwise follow. I have had no issues doing 4 dives a day for 5 days straight with 45min BT with the VR3 on the Prince of Wales and Repulse and have yet to be beaten up by any DIR divers

If doing a fixed single level dive I follow VPMB with the VR3 as a backup.

I like my VR3 - Id like it more if it had VPMB on board (but that will not be anytime soon according to latest info from DeltaP

[johnv]

Originally Posted by johnv

I hadn't forgotten this, and would still be interested in the examples as requested above.

what sort of lengths of deco are you doing this on?

John

Mark, can you post examples please, if you, and others you dive with, really are doing this type of mixed method deco on decent length dives, getting out of the water quicker and it's working then pretty much everyone here ought to be interested.

thanks in advance
John

[Mark Chase]

I will post you the profiles off line as I dont want what amounts to my personal experimentation on here.


ATB

Mark Chase