Suunto Dive Computer Question

[Antarctic-Adventurer]

According to the PADI RDP, when diving in cold water you should plan your dives as if they were 4m deeper than actual, to account for differences in nitrogen uptake. I dive with a Suunto D6 wrist computer. Does anyone know if these products make the adjustment automatically or do you have to 'tell it' manually?

Cheers,

A.A.

 

[paulwlee]

You have to tell it manually, using the P0~2 settings.
Which makes sense since a lot of it depends on other factors.
Someone diving 50 degree waters in a drysuit with adequate undergarments will be much warmer than someone diving 65 degree waters in a 3mm wetsuit.

Some manufacturers (Uwatec comes to mind) used to do this IIRC, not sure if they still do it. It sure is

A very relevant phrase here would be RTM. (sanitized version of RTFM )

 

[Antarctic-Adventurer]

Thanks for your reply paulwlee. I've read my manual cover to cover but this wasn't really covered. Correct me if I'm wrong, but don't the P0~2 settings just adjust the level of conservatism on the RGBM, which is not the same thing as planning your dives as if they were four metres deeper?
You make a good point about diving in a drysuit though. Does that mean that even in cold water in a drysuit adjustment isn't really required?:huh:

 

[drew52]

General rule of thumb is to be conservative. If you set your computer 1 level more conservative in cold water whether in drysuit or not you may have a couple minutes less bottom time but at least you will be slightly safer.

I can't comment on the Suunto as I do not have 1 but I would say 1 extra level more conservative would be fairly similar to an extra 4m on the rdp.

Easy check. Set your computer 1 level more conservative and then run the dive planner. Now compare max bottom time to the rdp for a particular depth using the 4m deeper plan for cold water diving. ( I hope that makes sense )

 

[johnny_bravo]

I have a D9 I'm assuming same menu as D6. P0 settings affect how conservative you want the computer to be to account for things like cold water. RGBM 50 setting instead of full 100 is simply attenuating the RGBM algorithm to make it less conservative.

RGBM 100 + P2 = the most conservative possible.

Hope this helps.

-J.-

 

[maged_mmh]

I have a Stinger, I think Suunto algorithm I conservative enough more than the RDP to account for such conditions as cold and currents, however if you feel that you're really in a bad shape you can use P0-P2

 

[Antarctic-Adventurer]

OK, thanks for all the responses guys. Do any of you with Suunto watches actually adjust the setting to P1 if you're drysuit diving in cold water, or just leave it on the default P0?

 

[paulwlee]

OK, thanks for all the responses guys. Do any of you with Suunto watches actually adjust the setting to P1 if you're drysuit diving in cold water, or just leave it on the default P0?

If you don't get much colder than in your other dives, then I don't see why you would want to adjust it. Now if you do get colder, then you just need a better undergarment or a thicker hood. When I do 80~100 minute runtime times with my drysuit in 48~52 degree F water, I'm warmer than when I used to do 40 minutes dives in my 5mm farmer johns in 65 degree water.