Suunto Dive Computers and Decompression Diving? Advice wanted

[Antarctic-Adventurer]

So I am getting to the stage in my diving where I want to expand the range of my horizon. There are some wrecks that I want to visit deeper than or very close to the standard PADI Recreational limits so I am thinking of enrolling on a basic tech course that teaches advanced nitrox and diving on air upto 50m. But what to do about dive computers? I currently use a Suunto D6 but am I correct in thinking that it is not really designed for diving beyond your NDLs? I know that it has an algorthym for calculating what deco time you must make if you do exceed your No Stop Time but is it just meant for emergencies only or can it be used to make a planned dive requiring a decrompression stop? Nothing extreme, just say you were to spend 15 minutes at 40m, you will have to do some deco time. According to the manual however if you go into deco, it bleeps at you like mad to ascend immediately. Perhaps you might not be ready to yet though if that was part of the plan?

Does anyone use their Suunto for making planned dives that they know will require deco stops? (All with the correct training).

If not what computer am I looking for exactly? Have been pretty happy with the D6 so far...

sorry this is such a long post. Hope it makes sense and catches someone's eye though.

AA

 

[Rainer]

I use Suuntos for my all my dives. In gauge mode. Should work just fine for what you intend.

 

[Antarctic-Adventurer]

I use Suuntos for my all my dives. In gauge mode. Should work just fine for what you intend.

But gauge mode doesn't provide any decompression data at all, it is just a timer and depth indicator. My question relates to using the Suunto D6 in DIVE mode (either air or EANx) not in gauge mode as I want to keep a track of decompression times. Sorry if I wasn't clear. What other computer do you use to track N loading if you are only using the Suunto in gauge mode?

 

[Rainer]

The one between my ears.

Don't most tech classes teach doing this?

Sure, we have deco software we consult before getting in the water, but we do all the tracking once under the surface.

 

[Antarctic-Adventurer]

The one between my ears.

Don't most tech classes teach doing this?

Sure, we have deco software we consult before getting in the water, but we do all the tracking once under the surface.

I see. I am sure that most tech classes do teach this as a basic. I guess I'll find out when I start...

Thanks for your input.

 

[Antarctic-Adventurer]

The one between my ears.

Don't most tech classes teach doing this?

Sure, we have deco software we consult before getting in the water, but we do all the tracking once under the surface.

Is it usual then for most divers not to use a specialized computer for decompression dives but work it all out previously on tables and then just watch the time?

 

[nereas]

If your dive computer has a "gauge" mode, then it can be used in conjuction with deco software or deco tables and slates to perform deco dives, once you are properly trained in deco procedures.

Deco procedures involve first choosing the appropriate mix for the planned depth (called MOD) for the dive. This is a combination of the proper oxygen fraction and nitrogen fraction, offset by helium for the balance to equal a 100% total. In order to be certified for helium usage, normally two trimix courses are also required, basic trimix for diving to 185 ft, and advanced trimix for deeper.

Deco procedures next involve choosing the appropriate allowable planned time at depth, which is mostly governed by the amount of gas you can feasibly take with you for the egression phase (the return).

Deco procedures thirdly involve choosing the appropriate deco mixes, normally 100% O2 for 20 ft, EAN 50 for 30 ft to 70 ft, TMX 30/30 for 80 ft to 130 ft, etc. However some courses are taught with EAN 80 for 30 ft, and EAN 36 for 40 ft to 120 ft.

Then you would complete your primary dive plan, for all mixes and allowable depths and times.

And finally you would plan for contingencies, in case one mix or other fails during the dive. This is why you need the slates.

You also need a backup gauge-timer, in most courses, the better ones. So if your current dive computer has a gauge mode, it will work fine for deco diving, yes; however you would still need a backup for most courses by most instructors.

It is a good class, often several classes related to each other, and you learn a lot, and it is loads of fun. Enjoy!

 

[Scared Silly]

I use my computer as a back up to cut tables and a bottom timer. Some do it visa-versa. Some do not use a computer just cut tables with two bottomtimers (one of which may be a computer in gauge mode). No serious diver would do a planned deco dive with out first planning it out with contingencies and backup devices.

As for using a Suunto for deco I use mine with the algorithm set at 50% I find this gives me similar times to my cut tables from m-plan. I think having similar times is important so that it and the tables are in sync and you are not trying do both schedules.

As noted above your course should cover much of this.

 

[Antarctic-Adventurer]

As for using a Suunto for deco I use mine with the algorithm set at 50% I find this gives me similar times to my cut tables from m-plan. I think having similar times is important so that it and the tables are in sync and you are not trying do both schedules.

Sorry but could you explain what an m-plan is and what cut tables are? Forgive my ignorance but until now I have only dived within recreational limits.
Using the dive algorithm set at 50% sounds interesting. What exactly are you saying that doing this gives similar times to?

Deco procedures thirdly involve choosing the appropriate deco mixes, normally 100% O2 for 20 ft, EAN 50 for 30 ft to 70 ft, TMX 30/30 for 80 ft to 130 ft, etc. However some courses are taught with EAN 80 for 30 ft, and EAN 36 for 40 ft to 120 ft.

Thanks for your responses. May I ask another question? Is it generally standard procedure in deco-diving to use a high O2 mix nearer the surface to speed up decompression towards the end of the dive, or is it dependent on the profile of the dive you have just done?

Out of curiousity, what courses and agencies did both of you choose to get your training?

 

[Tomeck]

I have D9 and I use for advanced nitrox. I can change three mix 21%, 50% or 100% of oxygen with D9 in water. D9 calculate all stop decompression time and I don't need a table. For D6, I don't know.