Advice needed for Suunto Vyper: switching from gauge to air modus impossible?

[Genesis]

V-Planner 3.22 by R. Hemingway, VPM code by Erik C. Baker.

Decompression model: VPM-B

DIVE PLAN
Surface interval = 2 day 0 hr 0 min.
Altitude = 0ft
Conservatism = + 2

Dec to 130ft (2) on Nitrox 30.0, 50ft/min descent.
Level 130ft 27:24 (30) on Nitrox 30.0, 1.48 ppO2, 111ft EAD
Asc to 100ft (31) on Nitrox 30.0, -30ft/min ascent.
Asc to 70ft (32) on Nitrox 30.0, -30ft/min ascent.
Asc to 50ft (32) on Nitrox 50.0, -30ft/min ascent.
Stop at 50ft 0:20 (33) on Nitrox 50.0, 1.26 ppO2, 20ft EAD
Stop at 40ft 2:00 (35) on Nitrox 50.0, 1.10 ppO2, 13ft EAD
Stop at 30ft 3:00 (38) on Nitrox 50.0, 0.95 ppO2, 7ft EAD
Stop at 20ft 2:00 (40) on Nitrox 50.0, 0.80 ppO2, 1ft EAD
Stop at 15ft 12:00 (52) on Nitrox 50.0, 0.73 ppO2, 0ft EAD
Asc to sfc. (52) on Nitrox 50.0, -30ft/min ascent.

Off gassing starts at 79.2 ft

The "stop" at 70' is just for the gas switch. The first actual stop is at 50'.

The Vytec on that same profile in the simulator shows 11 minutes of decompression, but a 10' ceiling at maximum time! Clearly, that is WAY more aggressive than VPM-B for the same profile.

If you're diving a computer LESS conservative than a Suunto for decompression diving, or even if you are approaching the NDLs on those computers, you may be diving a "bend-o-matic"! :boom:

 

[Scuba_Vixen]

Vicky
The computer will follow your profile and add deco time if you descend/ascend slower etc. That's not exactly the issue as I understand the statement. If you cut tables from the comp's software, and the comp failed on the dive, you'd be left with tables too liberal for your slow ascent or if you added the deep stops. Unfortunately, a comp that will follow a plan you make for yourself that will give you lazy exploratory descents and ascents, is a lot more complex than the vyper/vytec and they cost twice as much. Most people just can't justify the extra $$ for the comps you can download your profile to. It's often easier to just add fudge factors to what you have based on V-Planner or Gap or whatever you like.

Diving deeper and longer seems to escalate the expense exponentioally.


Darlene

 

[MechDiver]

vicky once bubbled...


The only situation I can foresee that Vyper will get beserk and do not allow you to make a 18-20m deep stop is IF you make a too long bottom time that the CEIL (first deco stop) will be BELOW 20meters (70'). In this case you'll be probably in deep **** anyway regardless of what computer you're wearing on your wrist... If you understand what I mean...

No, I don't understand what being below the 70' level has to do with a first deco stop. I've made deco stops more than twice that deep with no problem. Not using a computer though.
What do you see as the problem?

MD

 

[MechDiver]

Scuba_Vixen once bubbled...
Vicky
The computer will follow your profile and add deco time if you descend/ascend slower etc. That's not exactly the issue as I understand the statement. If you cut tables from the comp's software, and the comp failed on the dive, you'd be left with tables too liberal for your slow ascent or if you added the deep stops. Unfortunately, a comp that will follow a plan you make for yourself that will give you lazy exploratory descents and ascents, is a lot more complex than the vyper/vytec and they cost twice as much. Most people just can't justify the extra $$ for the comps you can download your profile to. It's often easier to just add fudge factors to what you have based on V-Planner or Gap or whatever you like.

Diving deeper and longer seems to escalate the expense exponentioally.

Darlene

Thanks Darlene. Thats pretty much the points I've been trying to get across.

MD

 

[nitroxbabe]

vicky once bubbled...


Can you explain better why the computer goes "beserk" or does not allow you to do these dives?
Although Suunto's computers do not have any integrated "deep stops" feature, they keep monitoring throughout the dive the nitrogen uptake. This includes everything that you do in your profile. If you stop at 20meters for two minutes, the computer will take that into account, most probably clearing a bit of your fast tissues N2 loading.

Vicky -
My Suunto Vyper absolutely does NOT allow for deep stops. It wants you to ascend at 33ft/m until you reach the ceiling and then stay there until your obligation is up.

As a matter of fact, I have had the darn thing continue to ADD to my obligation as I ascend, because I am not ascending fast enough! It even says right in the manual that is will do this.

This computer definately wants you to dive IT'S profile.

 

[Genesis]

It will only do that if the compartment controlling your obligation is still on-gassing. Deep stops generally should be short for this reason.

I''d love to see a profile demonstrating this - I've not seen that behavior myself, and I dive my Vytec into deco (intentionally) on occasion. I most certainly do NOT immediately ascend to the ceiling depth when I do either!

 

[vicky]

MechDiver once bubbled...


No, I don't understand what being below the 70' level has to do with a first deco stop. I've made deco stops more than twice that deep with no problem. Not using a computer though.
What do you see as the problem?

MD

 

[vicky]

MechDiver once bubbled...


No, I don't understand what being below the 70' level has to do with a first deco stop. I've made deco stops more than twice that deep with no problem. Not using a computer though.
What do you see as the problem?

MD

If you dive with a computer like Vyper, and managed to get the CEIL to something below 70'... well, I don't know when your birthday is, but you've got chances you'll be spending it UW still doing some deco stops , and seriously- to get a computer like Vyper to drop down it's ceiling so much means you've been abusing it too much. When you get the computer to display the first deco stop at 20m (70') it will probably ask you for something like 180 minutes deco stops, and perhpas even lock itself in gauge mode. Try to simulate a 50m/45min dive with SDM and see what happens.
On the contrary, Vplanner usually gives more deco stops, starting a greater depths. Perhaps it is because of the difference between VPM model and the compartment model used in the Vyper (it is not a true RGBM model like Suunto claims. There is a post from Bruce Wienke in this forum where he explains what the Suunto model is).
Anyway, since I find Vyper slightly liberal, I stick to my plans and don't ascend to whatever the Vyper asks me for. Still, I don't understand why you keep saying the Vyper forces one to dive the profile the computer wants.. You can read in the Vyper's manual that if you don't do the deco stops at their recommended depths, deco time will be longer (ASC TIME is calculated at the CEILING they recommend). So? No problem, do your planned deco stops and it will take longer than the Vyper's recommendation. This only proves that Vyper is not so conservative

 

[MechDiver]

vicky once bubbled...


Still, I don't understand why you keep saying the Vyper forces one to dive the profile the computer wants.. You can read in the Vyper's manual that if you don't do the deco stops at their recommended depths, deco time will be longer

That's exactly the point Nitroxbabe and I (I think) have been trying to make. You have no choice but to dive the computers profile, even if you know you have a better one more suited to the dive you're doing.

What I'm saying is the computer is not flexible, has flawed profile algorithems, and is not suited to deco diving beyond rec NDL limits. That's what tables and a B/T are for
Not knocken the computer per se, just the use.

And I understand now what you meant about the 70' depth. With the proper equipment suited to that style of diving, I decide how much deco I want to do, then decide on the depth and bottom time, and gas to accomplish that level of deco. You cannot do that with the Suunto. Any of them.

MD

 

[MechDiver]

Genesis once bubbled...
It will only do that if the compartment controlling your obligation is still on-gassing. Deep stops generally should be short for this reason.

I''d love to see a profile demonstrating this - I've not seen that behavior myself, and I dive my Vytec into deco (intentionally) on occasion. I most certainly do NOT immediately ascend to the ceiling depth when I do either!

The simulator software for the Vytec shows this very plainly and was the primary reason I didn't buy one.

Also, and just IMO, diving a recreational computer into a deco obligation, on occasion, is not the brightest thing to do unless you have the training and equipment to backup that style of diving.
YMMV.