You tell that Sim where to go!scubasean once bubbled...
LOL
I didn't say I use it....I was just saying what the sim said to me...
Suunto Vytec deco test... deco divers help.
- Thread starter jplacson
- Start date
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OP
jplacson
Guest
Oh... heaven's no... I have no intentions of doing deco dives without being certified for it! I'm certified for OW and basic Nitrox... I'm fine with that for now...I'm gonna dive a lot more before considering deco dives.
I'd just like to know that once I do start training (probably continue under TDI) for deco dives & advanced Nitrox, I'd like to know that my Vytec won't always get bent... or I'll always have to swtich to gauge mode... kinda useless having a computer that doesn't compute right?
I use my computer as a backup to my planned dives... something to confirm that I am following my plan, and that I'm within its NDL as well as the tables... I'll follow whichever one is more conservative at the time. ie; if the Vytec tells me during a dive that I have 2 min NDL left, while my plan gives me 5 min more... I'll follow the Vytec. If my Vytec allows a longer repeat dive than my plan, then I follow my plan.
I always stay within my plan & within my computer's NDL ... using the computer just as a verification that I'm within my plan AND the Vytec's model.
...
I want to know that when I do get certified for deco dives (particularly staged decos) ... I'd like to know that the Vytec's model will be close to the plan that I will make. So that I can at least know how to compensate for any discrepancies between the plan, and what the Vytec is beeping about.
...
I personally find the ascent profile of the Vytec aggressive... that's why I wanted to know if anyone ever took one down for staged decos...WITHOUT using gauge mode. And using the 3 mix (not trimix) function.
I'd like to know if this feature of the Vytec really works for deco divers.
I'd just like to know that once I do start training (probably continue under TDI) for deco dives & advanced Nitrox, I'd like to know that my Vytec won't always get bent... or I'll always have to swtich to gauge mode... kinda useless having a computer that doesn't compute right?
I use my computer as a backup to my planned dives... something to confirm that I am following my plan, and that I'm within its NDL as well as the tables... I'll follow whichever one is more conservative at the time. ie; if the Vytec tells me during a dive that I have 2 min NDL left, while my plan gives me 5 min more... I'll follow the Vytec. If my Vytec allows a longer repeat dive than my plan, then I follow my plan.
I always stay within my plan & within my computer's NDL ... using the computer just as a verification that I'm within my plan AND the Vytec's model.
...
I want to know that when I do get certified for deco dives (particularly staged decos) ... I'd like to know that the Vytec's model will be close to the plan that I will make. So that I can at least know how to compensate for any discrepancies between the plan, and what the Vytec is beeping about.
...
I personally find the ascent profile of the Vytec aggressive... that's why I wanted to know if anyone ever took one down for staged decos...WITHOUT using gauge mode. And using the 3 mix (not trimix) function.
I'd like to know if this feature of the Vytec really works for deco divers.
Well, kinda.
When you first enter deco on the Vytec it will show you "ASC TIME" (the MINIMUM time to reach the surface, plus the 3 minute safety stop) and the ceiling. It also shows you an upward pointing arrow, showing that you are still on-gassing, and "ASC TIME" flashes. The flashing and arrow means that you are still loading, and your required ascent time is increasing.
Note that the Vytec overstates the deco time by 3 minutes (as it adds the 3 minute safety stop in); more "extra conservatism" in theory, but be careful (as I'll point out below.)
The ceiling moves down as you remain at depth.
When you begin to ascend, at some point the upward pointing arrow will go away. When it does, you are offgassing and decompression has begun.
Now you can dive the Vytec as a "bend and sit" model, but I'd call that inadviseable at best. However, the computer doesn't force you to dive that profile for decompression, and you shouldn't!
Let's say I'm going to do a dive to 140' for 20 minutes, decoing on backgas. VPM-B gives me the following:
DIVE PLAN
Surface interval = 2 day 0 hr 0 min.
Altitude = 0ft
Conservatism = + 2
Dec to 140ft (2) on Nitrox 28.0, 50ft/min descent.
Level 140ft 17:12 (20) on Nitrox 28.0, 1.47 ppO2, 125ft EAD
Asc to 100ft (21) on Nitrox 28.0, -30ft/min ascent.
Asc to 60ft (22) on Nitrox 28.0, -30ft/min ascent.
Stop at 60ft 0:20 (23) on Nitrox 28.0, 0.79 ppO2, 52ft EAD
Stop at 50ft 1:00 (24) on Nitrox 28.0, 0.70 ppO2, 43ft EAD
Stop at 40ft 2:00 (26) on Nitrox 28.0, 0.62 ppO2, 34ft EAD
Stop at 30ft 3:00 (29) on Nitrox 28.0, 0.53 ppO2, 24ft EAD
Stop at 20ft 3:00 (32) on Nitrox 28.0, 0.45 ppO2, 15ft EAD
Stop at 15ft 13:00 (45) on Nitrox 28.0, 0.41 ppO2, 11ft EAD
Asc to sfc. (45) on Nitrox 28.0, -30ft/min ascent.
Off gassing starts at 84.2 ft
Note that VPM has me do a "stop" at 100', but its only to come to a full stop; there is no time associated with it. That's their "deep stop" (I dive with it enabled.)
The first deco stop is at 60', and its to synchronize the clocks (20 seconds.) I then do 1, 2, 3, 3 and 13. All I need to actually write down is 100:60/50/1,2,3,3,13, or stop at 60, then do 50, 40, 30, 20 and 15. If there's a decent surge I will reconfig for 20' as my last stop, and then the profile looks like 100:60/50/1,2,4,17.
The Vytec will start showing me in "decompression" at about 84'. If I am actually doing this dive, when I make my first real stop at 60' I am offgassing, and getting credit for the time.
By the time I get to 15', I am likely close to being "clear" on the Vytec! My experience with actual profiles suggests that while VPM will tell me I have more hang time to do, the Vytec is perfectly happy for me to get out and start drying off.
Don't you believe it.
I don't have any good way to plan Vytec mixed-gas dives (e.g. carrying a deco cylinder) since their plan function doesn't permit me to switch gas while using it. As such, you simply can't plan dives that way. But you must plan those dives, because you have to KNOW you can complete the schedule with the gas you are carrying!
So, the Vytec may be "ok" for "light deco" as a means to dive, provided you don't just go to the ceiling and sit, but rather do a "proper" deco curve, and you know you have the gas to complete the profile.
It is NOT ok for mixed-gas deco as a primary tool, as it lacks any planning functionality, although it can be ok as a backup.
As was noted, you need to understand this stuff to deco dive with reasonable safety. While it is possible to teach yourself, its probably a better idea to take a class - assuming you can find one with an instructor and agency that you approve of.
DeepTechScuba
Guest
You will normally always be diving in gauge mode on a decompression dive if you are using a Suunto.
Lets assume that you have a good reason to perform a deco dive, say to 120 ft for 30 mins with twin tanks of some kind. Suppose a shipwreck is down there that you want to go take photos of or make movies of.
120 ft is in that range of mild narcosis so that an air dive would be feasible for a depth like this. In other words, no helium required.
Then your first deco gas would be something in the rage of your first deep stop.
120/33 + 1 = 4.64 total ambient pressure
4.64/1.6 = 2.88 ambient pressure at your first deep stop
2.88 = 62 ft depth for your first deep stop
1.6/2.88 = 55% best mix at 60 ft depth
Therefore the best deco gas to use for a dive like this would be EAN55. You would be diving air to your MOD of 120 ft, staying for a total bottom time of 30 mins, then ascending to your first deep stop at 62 ft.
You could use EAN55 starting at 62 ft and all during your staged decompression, all the way back up to the surface, depending on your required deco time and your gas requirements. Or you could switch to EAN80 at 30 ft or to 100% O2 at 20 ft for further decompression. You would need stage tanks for each of the EANx gasses that you planned.
Your deco software would need to tell you the exact deco stages and times at those stops after you plug into it the desired deco gasses you want to use. Your deco software is going to allow you to select your gas tension tolerances. The more conservatively your make your selections, the deeper your first stop will be, and the longer your deco times at your various stages will be.
The disadvantages of the multiple gas dive computers is that the gas tension tolerances are built in. You do not have a lot of flexibility with them.
Lets assume that you have a good reason to perform a deco dive, say to 120 ft for 30 mins with twin tanks of some kind. Suppose a shipwreck is down there that you want to go take photos of or make movies of.
120 ft is in that range of mild narcosis so that an air dive would be feasible for a depth like this. In other words, no helium required.
Then your first deco gas would be something in the rage of your first deep stop.
120/33 + 1 = 4.64 total ambient pressure
4.64/1.6 = 2.88 ambient pressure at your first deep stop
2.88 = 62 ft depth for your first deep stop
1.6/2.88 = 55% best mix at 60 ft depth
Therefore the best deco gas to use for a dive like this would be EAN55. You would be diving air to your MOD of 120 ft, staying for a total bottom time of 30 mins, then ascending to your first deep stop at 62 ft.
You could use EAN55 starting at 62 ft and all during your staged decompression, all the way back up to the surface, depending on your required deco time and your gas requirements. Or you could switch to EAN80 at 30 ft or to 100% O2 at 20 ft for further decompression. You would need stage tanks for each of the EANx gasses that you planned.
Your deco software would need to tell you the exact deco stages and times at those stops after you plug into it the desired deco gasses you want to use. Your deco software is going to allow you to select your gas tension tolerances. The more conservatively your make your selections, the deeper your first stop will be, and the longer your deco times at your various stages will be.
The disadvantages of the multiple gas dive computers is that the gas tension tolerances are built in. You do not have a lot of flexibility with them.
Last I checked the Vytec was a 3 gas switchable computer, but I may be an idiot..
OP
jplacson
Guest
Genesis... I think Suunto left out the deco gas switching plan on purpose to keep non-certified divers from monkeying around with it and trying to do a PLANNED deco dive with it.
I honestly did not understand a word you said for your plan!!! :lol:
Seriously, thanks for the info... it's nice to kow that the Vytec CAN function as a BACK-UP COMPUTER...and not just as a glorified BT.
I'd like to use the gas-switching function someday too!!! It's nice to know that it's actually useful... when used as back-up to proper training and a well-planned deco dive.
I honestly did not understand a word you said for your plan!!! :lol:
Seriously, thanks for the info... it's nice to kow that the Vytec CAN function as a BACK-UP COMPUTER...and not just as a glorified BT.
I'd like to use the gas-switching function someday too!!!
It's nice to know that it's actually useful... when used as back-up to proper training and a well-planned deco dive.DeepTechScuba
Guest
O-Ring, I do not believe that there yet exists a diving computer with a good deco algorithm in it, whether for deco dives on air or deco dives on helium mixes, there just isn't.
Well, that "planned 140" dive is actually a dive that is just below 130, but I overstated the depth by a few feet (more conservatism!) for grins and giggles. I might touch 140, but only for a minute or two. (That is why the PO2 looks high - it is, if you sit on the bottom, but I have no intention of doing that )
Where I also find the gas switch capability useful is in a situation where you carry a pony bottle full of air on a NDL dive. If you have to switch to it, the switch capabiltiy gives you the ability to have the computer know what you did, thereby not invalidating its computations for further dives.
Why air in the pony? Simple - its encourages frequent topping off, so ITS FULL! A half-empty pony is not a good idea, and dumping mix gets to be expensive (if you're paying for it) or a pain (if you're not); I want my bottle full, and have it full of air, as a bailout, makes that easy.
)Where I also find the gas switch capability useful is in a situation where you carry a pony bottle full of air on a NDL dive. If you have to switch to it, the switch capabiltiy gives you the ability to have the computer know what you did, thereby not invalidating its computations for further dives.
Why air in the pony? Simple - its encourages frequent topping off, so ITS FULL! A half-empty pony is not a good idea, and dumping mix gets to be expensive (if you're paying for it) or a pain (if you're not); I want my bottle full, and have it full of air, as a bailout, makes that easy.
are claiming that a new model of the M1 is available that is full-up RGBM with deep stops and "proper" shaped deco.
Single mix though..... at least I think it is.
I've had no success getting any real info on it other than a single web page linked off Weinke's web site, and none of the dealers seem to know anything about it.
100days-a-year
Contributor
55% best deco mix?? WTH??A name change may be in order.
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