Stop depths

[Fathoms Down]

Originally Posted by Garf

Personally I would use the vytec as a timer in guage mode and plan using another tool. The Suunto algorithym is waaaaaay too aggressive for me.

I did a 41m dive for 61 minutes and used my Vytec once (left my VR3 at home) and I would never, never use it for deco diving again. The agressiveness is truely loopy.

I'd set it in to gauge mode and use tables if I were you. ProPlanner, GAP, V-Planner, etc would be perfect to cutting the tables and would give deep stops and the final stop depth you want.

[jptaylor9]

Originally Posted by JohnD

same as myself then. but but how do you work out your first PROPER stop depth (not pyle/WKPP stops) your Vytec only gives a ceiling (as I keep saying) Is the computer the most efficient, or do you work out your stop depths beforehand (using a PC-based planner) so that if your Suunto packs in during a stop you can then go to your laminated runtimes and continue on those times, and get out of the water to dive again...............

The computer is more efficient, assuming you trust the model it uses, as it will be based on your actual profile. pre-planned tables assume a square profile with set ascent/descent rates.

The "ceiling" depth is the stop depth on the computer, come up to just below that depth & do stop. It's a good idea to carry backup tables but you'll need a seperate dive timer or computer in gauge mode. If your Vytec packs up, you cant use it as a timer for your backup tables.

[Garf]

my apologies john, it read like you were asking how to deco dive.sorry bout that.

Anyway, if you are flying the vytec, then the ceiling is the first stop depth

Shallow, aint it

The suunto model iss about shallow stops ang getting you up and out quick. This is, imho, bolox. It benefits a great deal from being padded out, but why bother when there are other options. I used to deco dive with a stinger, but gave up after realising I felt decidedly fizzy going straight up to shallow depths. Since then, and b4 getting a vr3, I dived with tables, which were less efficient, but far gentler, again imho. I agree with Nick that I would never use a suunto on a deco dive in anything other than guage mode, but that's my opinion and choice I guess . I prefer 20/80 gradient factors, which give a similar profile to the vr3, and thus use decoplanner to cut backup tables for the vr or just dive the tables.

I guess the tricky thing is going to be working out how much hang time the vttec will give you, but does it not have a simulation mode?

[gobfish1]

Originally Posted by JohnD

below you will find the first dive I asked about planned on the PC using Zplanner. these runtimes will be laminated and carried along with alternate plans. for instance longer, deeper & bailout etc.

Waypoint at 43m for 25:00 (27) on Air, PPO2 1.107, END 43
Deep Stop at 27m for 2:00 (31) on Nitrox 36.0, PPO2 1.325, END 27
Deep Stop at 21m for 2:00 (33) on Nitrox 36.0, PPO2 1.111, END 21
Deep Stop at 15m for 2:00 (36) on Nitrox 36.0, PPO2 0.896, END 15
Norm Stop at 6m for 1:00 (43) on Nitrox 65.0, PPO2 1.037, END 6
Norm Stop at 3m for 12:00 (58) on Nitrox 65.0, PPO2 0.844, END 3

TOTAL DECO TIME: 19 minutes.
DIVE RUN TIME: 58 minutes.
CNS Total: 20.2%
OTU's: 57

Time to Fly: 3.0 Hours

3203.7 Ltr. of 21.0% consumed.
526.9 Ltr. of 36.0% consumed.
400.3 Ltr. of 65.0% consumed.
4130.9 Ltr. total open circuit gas consumed


why 36% & 65%? that Is all the O2 I could get out of the cylinders at clubhouse last night.......

profile states you have Trimix training .
thats a bad gas choice / i would do that dive on a twins /air or nitrox plus 3l of o2 , or 72% 84%

would use my Vytec plus 2 deep stops half the depth +10


run your zplan on 10% or 20% and your in the ball park , the vytek will still give you more deco

Steve G

[Mark Chase]

Originally Posted by JohnD

I know all about PC based planning programs such as Zplanner/Vplanner, but if you just dive using the Vytec on Air/nitrox mode (not as guage) how do you pick your depths?

I dived a Vytec for a while on deep air and trimix up to 30% He using two deco gas's. I planned the dive using Decoplanner on a 20/80 GF and did the deep and intermediate
stops recommended by Decoplanner then cleared the Vytec on the shalow stops. Ocasionaly the Vytec would throw in a stop so I would just clear that to. I found little diferance on a square profile dive between the VR3 on 0 safety and the Vytec. The vytec was slightly more conservitave adding about 3 -6mins to the deco on a 45min bottom time at 45-50m using the Nitrox setting on say 23/25Mix.

Deeper than 50 I used tables because I was using more than 30% He in the mix.

This worked fine FOR ME and it was only when 50+ became a regular occurance that I switched to tables then on to a VR3.

The VR3 often gives big jumps in deco stops but I ignore them and just addd my own stops. Today with 60mins at 30 -36m it gave me2 @ 21 4 @ 14m and 5 at 4.5 so I added stops at 18m 12m 10m and 6m

The diferance with the VR3 is it will credit you for this and reduce the 6m stop. The Vytec will not credit you unless you are at or close to its recommended stop depth. It will often ADD deco if you add deep stops.

Be prepaired to do more deco than expected when you leave the bottom and its fine.

ATB

Mark Chase

[SimonK]

Doing the sort of dive we are talking about 25min @ 40m on air with 50% deco I plan using V planner and use a dive timer and Vytec. I find that on leaving the bottom the Vytec shows roughly the same time to surface as the schedule, and that the Vytec clears at about the same time that the schedule finishes.

The only time the two get seriously out of sync is if I do the final stop at 6m when the Vytec wants me at 4-3m. In this case the computer will ask for 5 to 10 min more deco.

I guess sunnto would say you should ascend at the rate indicated by the difficult to see graph up the side of the screen and then follow the ceiling up. They must have tried it out on some brave soul.
However it seems to me that the machine won't penalise you for doing deep stops from V plan or one of the GF programs.

As to why use the computer at all, why not just stick to tables and a timer? well I like having the extra info source and the flexibility when the dive profile isnt square.

Simon

[JohnD]

Originally Posted by gobfish1

profile states you have Trimix training .
thats a bad gas choice / i would do that dive on a twins /air or nitrox plus 3l of o2 , or 72% 84%

would use my Vytec plus 2 deep stops half the depth +10 Steve G

Gas availability is a problem for the dive this weekend, so I have to use what I have. I like to keep to an END of 40metres or PPN2 of 3.95, but this is what I have in my twin 12s (using the "rule of 1/3s). I personally would not use a 3litre for anything but a pony, not enough gas available using "rule of 1/2s" for deco for your buddy if he loses his. I will be using 7.5litre sideslungs, more gas available.
GARF, I cant work out the simulation mode on the dive manager software using multiple mixes, but I can do it using the Vytec itself as it changes to the next gas (at its max PO2 set) as you ascend.

[gobfish1]

Originally Posted by JohnD

Gas availability is a problem for the dive this weekend, so I have to use what I have. I like to keep to an END of 40metres or PPN2 of 3.95, but this is what I have in my twin 12s (using the "rule of 1/3s). I personally would not use a 3litre for anything but a pony, not enough gas available using "rule of 1/2s" for deco for your buddy if he loses his. I will be using 7.5litre sideslungs, more gas available.
GARF, I cant work out the simulation mode on the dive manager software using multiple mixes, but I can do it using the Vytec itself as it changes to the next gas (at its max PO2 set) as you ascend.

Well you talk the talk , so i will say no more ,
have fun ,

Steve G

[Mark Chase]

Originally Posted by JohnD

GARF, I cant work out the simulation mode on the dive manager software using multiple mixes, but I can do it using the Vytec itself as it changes to the next gas (at its max PO2 set) as you ascend.

Yeah this realy pissed me off when I used my Vytec for deco. I complained in writing and personaly at the Suunto stand for all the good it did me. Whats the point in producing a three gas computer and providing a dive planning package that cant work on three gasses? I pointed out the safety implications to them stating that it was dificult to gas plann the deco dive and therefor dangerous as mistakes could easily be made. This didnt cut much ice either >.

Ho Hum

One day when I rule the world............

ATB

Mark Chase

[Janos]

Originally Posted by Mark Chase

Yeah this realy pissed me off when I used my Vytec for deco. I complained in writing and personaly at the Suunto stand for all the good it did me. Whats the point in producing a three gas computer and providing a dive planning package that cant work on three gasses? I pointed out the safety implications to them stating that it was dificult to gas plann the deco dive and therefor dangerous as mistakes could easily be made. This didnt cut much ice either >.

Yes it's an arse.

But then if you read the blurb at the beginning it says it shouldn't be used for deco. (I think it does. Or perhaps that's a different Suunto. One of mine did (I used to have a favor before I lost it in Porthkerris carpark.))

Janos