Vr3

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MechDiver once bubbled...
AquaTec,

My impression of the VR3 from that manual was that it would recompute your profile on the fly. IOW, you stay at depth longer or, as in your last post, not do a stop, and it would refigure your remaining profile based on that new info, gases, etc. That would not seem to be the case based on your last post. Or does it do that, but give you the "use tables" message in the bargain?

Phil

maybe i didn't explain it very well.

on the screen there are several icons. in the top right corner you have a choice of eather a clock or a graph showing nitrogen loading. the only time it goes into a "use Tables" mode is when you miss two [i think] deco stops and there are some peramiters for this, like ascending past the stop by 5 feet or something.

the "use tables' icon then replaces the clock/graph icon
but the information regarding deco is still visable
The VR3 will then provide a "best Guess" scenario for decompression, it displays it the same as if you followed the proper profile other than the icon mentioned earlier.

as with any computer it calculates your profile on the fly throughout the dive

you can stay at depth as long as you want i believe it will provide unlimited deco information were some are limited to 999 minutes

does this explain it

here is a link to ProPlanner free shareware planning software

link to the VR3 and picture
http://www.omsdive.com/computer.html
you will see in the pix that it is calling for a gas switch this will override the "use Tables" icon but be in the same place
 
AquaTec once bubbled...
does this explain it

here is a link to ProPlanner free shareware planning software

link to the VR3 and picture
http://www.omsdive.com/computer.html
you will see in the pix that it is calling for a gas switch this will override the "use Tables" icon but be in the same place

Yep, that sunk in finally. Thanks for the additional clarification and I'll give the software a spin.

Phil
 
Aquatec Said
"A quick question for you ...how do you plan your deep stopsI take half the distance between my first stop and my max depth and make that my first deep stop, then do it again between those two stops until i have reached my first deco stop. the VR3 does something simular but it tends to end up slightly deeper."


Your method is basically Pyle stops, Thats one of the ways I'll do it.. and gets you up the line faster..

Another method which will generate profiles similar to GF profiles is to do your first stop at 80% of your max depth, then do stops every 10 feet.. its not exact but will put you on a Deco curve that approximates GF. On OC you may get some additional gas loading (on the slower compartments) if its done before the calculated off gassing point for your mix, but on An RB there really isn't a penalty since your mix is constantkly getting richer with o2...

Debate is a good thing.. People get to see each others point of view and hopefully both learn something (as are others who are following the debate), and maybe try something new. I'm not against using the VR3 (I do use it), I'm just saying its deco profiles are different than I'm used to run.. More modern adapted Buhlman algs don't really work based only on nitrogen (the earliest hacks did they built in some concervatism to simulate faster loading of He), most modern software calculates the total compartment loading based on both gasses in proportion to the mixes and the allowable gradient for both gasses. Some can even predict the overloading of compartments based on an imporper gas switch (being SATURATED with a slow gas like nitrogen THEN switching to a light gas like helium).
When deco programs calculate percentages and PO2 its not just based on the gas compsition, but as stated above.. 32% oxygen really isn't a PO2 of 1.6 @40m ist actually less due to Water vapor and CO2.
I don't consider myself an expert (in reality noone should) since its all theory, and models based on our current understanding anyway..
Non CCR programs also used a fixed value for water vapor and CO2, whereas rebreather capable programs take into account the variable potential of water vapor based on loop temperature.. standard OC uses a temp of 35C since its assumed all inhaled gas will be warmed to body temperature, whereas a loop in general is warmer and may be above body temp.. also the method used to calculate ascents had to be changed since on OC takeing the average between the deepest and shallowest points work for gas loading, it doesn't work for constant PO2.

WHen I said leaving the VR3 at home on air based dives its not necessarily a recreational dive.. Depending on where I am and the availability of He I may or may not have it in my mix, but it still may be a deco dive.
 
the only time it goes into a "use Tables" mode is when you miss two [i think] deco stops

Afraid not - I missed one deep stop by about 1m or maybe 2m and when I noticed I could not get down quick enough to get the deep stop, you have 1 minute and it counts down for you. If you can get back down then then it starts reversing the count and let's you finish the stop.

Why could I not get down that 1m? When I noticed I had about 20 seconds to go and I was in the middle of Sara's flight deck......
 
Jonathan once bubbled...


Afraid not - I missed one deep stop by about 1m or maybe 2m and when I noticed I could not get down quick enough to get the deep stop, you have 1 minute and it counts down for you. If you can get back down then then it starts reversing the count and let's you finish the stop.

Why could I not get down that 1m? When I noticed I had about 20 seconds to go and I was in the middle of Sara's flight deck......

I wasn't sure about this, the only time i missed eep stops was in Truk Lagoon on a wreck at 220 feet for 60 minutes, the ascent required an up the ladder through the gangway down to another level then out through a cargo hold. well somewere in there you are supposed to do a couple of deep stops. and i missed it every time. i would still do them but only on my final ascent not the up and down part. but to late it went innto missed stop mode.

I found that if you started deco. say you are on your first deep stop, then descend down again. say inside a wreck, it also puts you into "Use Tables" mode

Of all the diving I have done with it,. the unit has gone into "Use Tables" mode only a couple of times mostly on these wrecks
 
It completely blows my mind that you guys would pay more than $1000 (sometimes as much as $2000!!) for something that is totally useless and not needed.

Learn how deco works and you won't need to rely on a computer and can spend that money on things you really DO need like more regs or stages or a trip to your favorite destination.

What are you afraid of? You need a machine on your arm to tell you it's ok to get out of the water?? :bonk:
 
WYDT once bubbled...
It completely blows my mind that you guys would pay more than $1000 (sometimes as much as $2000!!) for something that is totally useless and not needed.

Learn how deco works and you won't need to rely on a computer and can spend that money on things you really DO need like more regs or stages or a trip to your favorite destination.

What are you afraid of? You need a machine on your arm to tell you it's ok to get out of the water?? :bonk:

You always state your position so eloquently Rob. You, of course, use nothing but deco-planner, right? And you have how many years of trimix experience?

Terms like "useless" are relative in my experience.

Tom
 
WreckWriter once bubbled...
You always state your position so eloquently Rob. You, of course, use nothing but deco-planner, right? And you have how many years of trimix experience?

Terms like "useless" are relative in my experience.

Tom

Ok Tom, I take that back... computers aren't completely useless... they can make a nice (albeit very expensive) paperweight. :wink:

In all seriousness: No, I don't have a lot of Trimix experience but I do have a lot of deco experience and I haven't used a computer yet... and neither do the guys/gals who do have a lot of trimix experience that I dive with (including a trimix instructor).

I think simpler is better and using a computer might seem simpler on the surface but it's not.... you still have to have tables in case the computer dies anyway right? So why even use it in the first place??? I just don't get it....

If the argument is against square profiles aren't most "trimix" dives pretty square? If not one can use an avg depth with tables too... I do that all the time in the caves. I know most technical wrecks are a square profile....

I'm not trying to hammer on the people who use computers I just don't understand it... sure they look cool and make great conversation pieces but they are so expensive (even most of the EANx models are $400 and up) that I just don't see any benefit and for technical diving I just think they are useless.

If one studies decompression theory and looks at all the information out there and really gets a good feel for how it works it's easy.

What I do: Print out a set of tables with Decoplanner's "Table's" feature. I print out tables for all the standard mixes I'll be using both with and without deco gas and the range I'll be using them at. I cut them into strips that will fit in my wetnotes and then laminate them and put them in my wetnotes.

Also I'll say now that I don't follow the tables decoplanner puts out exactly. I add deep stops and take some time away from the 20ft stop and do a very slow ascent along with some other minor adjustments.

Once one does the same dive a couple of times this way one won't even need to look at the tables anymore.

This is the advantage of not using or relying on a computer and using standard mixes. One gains a better feel for how things work and saves a lot of cashola in the process.

DSAO!!
 
For me the computer is the backup. What I do is to cut tables prior to the dive (I prefer V-planner to deco-plan as it gives me a better deep stop most of the time), I then do the deep stop the computer calls for to keep it from going into "use tables" mode (an 80% of max depth stop for 1 minute usually, sometimes 2) then deco out on the tables, occasionally checking myself with the puter. The tables and computer are rarely more than a minute or two apart throughout the whole deco.

I bought the computer prior to my mix class. Had I not done so I likely wouldn't have bought it but now I have it and I feel its a good backup in the case where a dive goes outside the planned for range.

Yea, most mix dives are fairly square, not all though. A good exception is the Spiegel Grove. A shallow mix dive for sure but far from square when you get to crawling around inside.

Looking forward to meeting you on the Gulf trip on the 22nd.

Tom
 
WYDT
It completely blows my mind that you guys would pay more than $1000 (sometimes as much as $2000!!) for something that is totally useless and not needed.

Learn how deco works and you won't need to rely on a computer and can spend that money on things you really DO need like more regs or stages or a trip to your favorite destination

What are you afraid of? You need a machine on your arm to tell you it's ok to get out of the water??

I was going to blast you for making the above offensive statements without intoducing the way you do deco, but i had to run out, and when i got back you had submitted the post below. Good for you.
everybody is entitled to their oppinion, it doesn't supprise me that yours is offensive, and demeaning considering your training.
you ar eright if computers were totaly useless and not needed then it would be a huge waste of money..you are correct in the fact that they are not needed at all, however they are usefull by making your dive more efficiant, felxible, and deco more reliable.

I do need..no ....like to have...yes.....a machine on that says it is safer for me to get out of the water, even providing a graph showing compartment loading, which is a benificial part of that deco process.

If you don't mind i would like to address some of your comments, not in order to convince you to change the way you do things, but to educate you in the way others might do it, so you will consider that prior to barking comments down from your high horse. since this thread is on the VR3 i will keep my comments associated to that


In all seriousness: No, I don't have a lot of Trimix experience but I do have a lot of deco experience and I haven't used a computer yet... and neither do the guys/gals who do have a lot of trimix experience that I dive with (including a trimix instructor).
As i stated before...anybody pushing the limits of decompression theories and procedures and using trimix will find to there advantage the use of the VR3, i described why in posts above.
as you stated you do not have much experience so you probably don't need a computer at all until you get more experience.

I think simpler is better and using a computer might seem simpler on the surface but it's not.... you still have to have tables in case the computer dies anyway right? So why even use it in the first place???[
Why use a dive computer on the surface, i carry two computers, with my dive buddies two computers as back up to my back up. who needs tables...

I just don't get it...
that is the most accurate point you have made so far

If the argument is against square profiles aren't most "trimix" dives pretty square? If not one can use an avg depth with tables too... I do that all the time in the caves. I know most technical wrecks are a square profile....[
once again you are displaying your lack of experience and the lack of experience of those you tell you what to think over a beer after their dive.
any table dive will be a square dive as far as planning goes, that is why computers offer such an advantage over tables. you can use average depth for planning deco. but you loose flexability and accuracy it is the good old George rule of thumb method.
with a VR3 depth and time are completly flexible, you can do saw tooth dives at any depth for any time, and take advantage of the offgassing [or i should say, less on gassing] at the shallower portions of the saw. it is calculated every couple of seconds.
say at 300 - 400 feet every minute will add exponesualy to your deco commitment. with the VR3 you monitor your deco commitment and dive were you want and for how long.

I'm not trying to hammer on the people who use computers I just don't understand it
another true statement, I couldn't have said it better myself

that I just don't see any benefit and for technical diving I just think they are useless.
As you gain more experience and expand your thinking and circle of divers you encounter, the benifits might become clearer

If one studies decompression theory and looks at all the
information out there and really gets a good feel for how it works it's easy
this is very true, see we think the same on many of your statements

Like I said it is interesting to read and good backup for your original statements that you have posted your methods below

You are basicly a table diver, table generated by a comnputer on the surface. nothing wrong with that, i do like how you indicate that you you don't really follow the tables you make anyways, you add this and take away that. this is a good display of not understanding decompression or how to generate proper tables.
maybe you should look at a different deco planner that works for you instead of guessing...oh i forgot you are only aloud to use that one..to bad..well keep guessing and hopefull it all works out for you.


What I do: Print out a set of tables with Decoplanner's "Table's" feature. I print out tables for all the standard mixes I'll be using both with and without deco gas and the range I'll be using them at. I cut them into strips that will fit in my wetnotes and then laminate them and put them in my wetnotes.

Also I'll say now that I don't follow the tables decoplanner puts out exactly. I add deep stops and take some time away from the 20ft stop and do a very slow ascent along with some other minor adjustments.

Once one does the same dive a couple of times this way one won't even need to look at the tables anymore

This is the advantage of not using or relying on a computer and using standard mixes. One gains a better feel for how things work and saves a lot of cashola in the process.
 
https://www.shearwater.com/products/swift/
http://cavediveflorida.com/Rum_House.htm

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