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ku1111 · April 7th, 2008, 08:22 AM

Quote: (Originally Posted by gerstl_ossi)

Hi DIR guys, i normaly dive with a CCR Rebreather and use a Shearwater Pursuit diving computer or, and a VR3 but would have some help on Ratio Decompressing used by DIR.
Example:
48 Meter 30 Min BT
DECO Min (= BT + 5 Min (as 48= 45 Mt. +3) = Totale Deco 30+5 = 35 Min

80% first Deepstop = ATA 5,8/10 = 0,58x2= 1,16 5,8-1,20 = 4,6 ATA=36M

Deep Time Mix.
48 30 18/45
36 Mt. Deep 1 min
33 Mt. Deep 1 min
30 Mt. Deep 1 min
27 Mt. Deep 1 min
24 Mt. Deep 1 min

18 Min (50% 21-9 Meter)

21 Mt. Deco 3 min on 50/25
18 Mt. Deco 3 min
15 Mt. Deco 4 min
12 Mt. Deco 4 min
9 Mt. Deco 4 min

6 Mt. Deco 18 min on Oxygen

Would that be the decompression You use? Or are there errors in my interpretation?

Thanks a lot
and save diving on Your twinsets
Oswald

Not that it would kill you ;-) But from 65% of ATAmax (= 27m) you would double the deepstop time. From 21 to 9 DIR divers often follow a S-curve (read that ratio deco paper from the previous post)

If you want an example for your 60m dive there's an article (in Dutch) on a decompression presentation by Kees Hofwegen for DIR-NL on <click> GAP Decompressie Software </click>. You'll find a table in there comparing several decompression models for a 30 minute dive to 60m with TX18/45 and EAN50 + O2 for decompression.

When I read the ratio deco paper I come to the conclusion that for 30 minutes on 60m you would have 60 minutes deco (ratio 1:2 for 66m) - 10 minutes because you are 2 x 3m shallower then 66m. Total 50 minutes deco. Half you spend in the 21 - 9m segment and half you spend in the 6 - 0 segment. Half of the 21 - 9 (EAN50) segment time is spend in the 36 - 24m segment.

If you do that you get a profile that is close to what is shown in the article.

As you might have guessed by now I'm not (yet) GUE TECH educated so be warned. And I find that GUE TECH educated people often don't give the level of detail that you probably want/need.

Cheers

Marcel

April 7th, 2008, 08:22 AM	#6 (permalink)
ku1111(Offline) New Member Join Date: Jun 2006 Location: Netherlands Posts: 21	Quote: (Originally Posted by gerstl_ossi) Hi DIR guys, i normaly dive with a CCR Rebreather and use a Shearwater Pursuit diving computer or, and a VR3 but would have some help on Ratio Decompressing used by DIR. Example: 48 Meter 30 Min BT DECO Min (= BT + 5 Min (as 48= 45 Mt. +3) = Totale Deco 30+5 = 35 Min 80% first Deepstop = ATA 5,8/10 = 0,58x2= 1,16 5,8-1,20 = 4,6 ATA=36M Deep Time Mix. 48 30 18/45 36 Mt. Deep 1 min 33 Mt. Deep 1 min 30 Mt. Deep 1 min 27 Mt. Deep 1 min 24 Mt. Deep 1 min 18 Min (50% 21-9 Meter) 21 Mt. Deco 3 min on 50/25 18 Mt. Deco 3 min 15 Mt. Deco 4 min 12 Mt. Deco 4 min 9 Mt. Deco 4 min 6 Mt. Deco 18 min on Oxygen Would that be the decompression You use? Or are there errors in my interpretation? Thanks a lot and save diving on Your twinsets Oswald Not that it would kill you ;-) But from 65% of ATAmax (= 27m) you would double the deepstop time. From 21 to 9 DIR divers often follow a S-curve (read that ratio deco paper from the previous post) If you want an example for your 60m dive there's an article (in Dutch) on a decompression presentation by Kees Hofwegen for DIR-NL on <click> GAP Decompressie Software </click>. You'll find a table in there comparing several decompression models for a 30 minute dive to 60m with TX18/45 and EAN50 + O2 for decompression. When I read the ratio deco paper I come to the conclusion that for 30 minutes on 60m you would have 60 minutes deco (ratio 1:2 for 66m) - 10 minutes because you are 2 x 3m shallower then 66m. Total 50 minutes deco. Half you spend in the 21 - 9m segment and half you spend in the 6 - 0 segment. Half of the 21 - 9 (EAN50) segment time is spend in the 36 - 24m segment. If you do that you get a profile that is close to what is shown in the article. As you might have guessed by now I'm not (yet) GUE TECH educated so be warned. And I find that GUE TECH educated people often don't give the level of detail that you probably want/need. Cheers Marcel Last edited by ku1111; April 7th, 2008 at 08:50 AM.