Suunto Vytec

[R-T]

I should have specified the DS model.
I've been doing this long enough now that the argument for just diving tables is gaining validity. However most times the actual profile of the dive can vary widely from the original plan and as we know this is where the computer is most useful. On any planned square profile or multilevel dives esp any with any amount of squirrel gas I use the Vyper in gauge mode with a Uwatec timer as backup.

 

[Scared Silly]

My VytecDS when set at the 50% RGBM and using deep stops matches my cut tables close enough that it is a back up computer which is what I wanted it to be instead of an expensive guage which I think the Vyper turns out to be. As others have said the new Vyper2 and Cobra2 will allow a single gas change (2 total), do deep stops and switch between 50% and 100% RGBM**. Which makes the Vyper2 worth looking at as a backup to the tables. Not sure why they added all this to the Cobra2.

** I was told by the Suunto rep at DEMA that they could switch models but this is not listed on Suunto's spec sheet. If one can not switch to the 50% RGBM model then it is still an expensive gauge.

 

[paulwlee]

extracts from the manual :

The Suunto RGBM/ Deep Stop Algorithm

Yes, I looked at the manual, and looks like all the 'deep stop algorithm' does is to mechanically insert deep stops, the same way it does safety stops.
So, if I am correct, if you can remember to stop for a minute using the same simple rules, i.e. halfway between bottom and ceiling, and then halfway between that and ceiling, etc. with a non-DS Vytec or Vyper, then you will in fact get exactly the same calculations as with the DS models.

Thus the DS 'algorithm' is not a wholly new algorithm, but just the old algorithm with deep stop reminders tacked on. May be good for a brainless diver, but marginally useful for anyone who has learned about and does deep stops already.

 

[Jorbar1551]

i just ordered my vytec ds yesterday. i hope i get it soon!

 

[R-T]

So, if I am correct, if you can remember to stop for a minute using the same simple rules, i.e. halfway between bottom and ceiling, and then halfway between that and ceiling, etc. with a non-DS Vytec or Vyper, then you will in fact get exactly the same calculations as with the DS models.

Speaking from experience the current models penalize you for any intermediate stops if you add a deep stop on top of an existing dec obligation all you get is more time between 30' and the surface. This is what has become a sore spot for me. Comparing the same profile between the Vyper with A0 and P0 settings and VPMB with a +1 setting I've seen as much as a 20 minute difference.

 

[paulwlee]

Speaking from experience the current models penalize you for any intermediate stops if you add a deep stop on top of an existing dec obligation all you get is more time between 30' and the surface. This is what has become a sore spot for me. Comparing the same profile between the Vyper with A0 and P0 settings and VPMB with a +1 setting I've seen as much as a 20 minute difference.

Yes, it will penalize you if you are still under the floor when you do the deep stops, where you are still on-gassing according to a Buhlmann model. If you are above the floor but not at the ceiling, it will not penalize you, but won't credit you fully for the off-gassing, as you are off gassing more slowly. According to a Buhlmann model this is completely valid. If you do a slower ascent, (with deep stops and all) you will end up having to do a longer deco overall as you are not offgassing at the maximum rate during your deco. Now there is an arugment that with deep stops you will have better circulation and thus need less time than a Buhlmann model would indicate, but it's your call to believe it or not.