setting pri and sec handsets differently???

**Dsix36** · 9th December 2007, 13:26

Yesterday I did a dive of 2hr 15min at an average depth of 68'. I have always run my GF at 10/100 and stayed alive (awfully tired and my knees ached that night).
Yesterday I ran my primary GF at 25/85 and my secondary at 10/100. At 1hr 36min into the dive my primary was showing 4min of deco (first stop at 20') and the secondary was showing 38min (first stop at 50').
I set the dil to 21/35 on both handsets. I checked the setting at depth and after the dive. Everthing seems to be right.
Anyway I did the longest deco to be safe (not tired or achy knees last night), but I can't believe that these are right.
I thought that the first number in a GF would put the first stop deeper as the number was smaller. Is this not correct? It seems to me that 10/100 should have had deeper stops and got me out of the water sooner than 25/85.
Any help or advise will be appreciated. I am not a rocket scientist (yet) but I thought that I understood the principals of GF's
Help, I am sooooooo confused.

***ScubaDadMiami*** · 9th December 2007, 20:57

I am going to guess that if you did a deeper dive, the pattern you thought would come out would be more like the result you would have gotten. In your particular dive, your decompression obligation was so little that the "10" started you on deeper stops, as it would, but in order to make intermediate stops scaling up to the M-value over the course of the ascent, it ended out adding time to the overall runtime for the dive.

**Dsix36** · 9th December 2007, 21:08

Nope, no deeper dive. 72' was the max depth for the dive.

**wedivebc** · 9th December 2007, 21:15

Quote: (Originally Posted by Dsix36)

Nope, no deeper dive. 72' was the max depth for the dive.

I think the point is it's hard to generate accurate "deep stops" on a dive that has (assuming a 1.2 sp) an EAD of 42' or so. I will bet if you try those same settings on a deeper dive you will get the results you expect

**Dsix36** · 9th December 2007, 22:00

Quote: (Originally Posted by wedivebc)

I think the point is it's hard to generate accurate "deep stops" on a dive that has (assuming a 1.2 sp) an EAD of 42' or so. I will bet if you try those same settings on a deeper dive you will get the results you expect

I will definitely be trying just that next weekend. Thanks for the advice.

gerstl_ossi · 9th December 2007, 22:02

Quote: (Originally Posted by Dsix36)

I thought that the first number in a GF would put the first stop deeper as the number was smaller. Is this not correct? It seems to me that 10/100 should have had deeper stops and got me out of the water sooner than 25/85.
.

Hi, thats right, 10/xx should have a deeper first stop than 25/xx and xx/100 should have shorter decos as xx/85 or xx/70.
But as Your diving was not that deep (70" - something like 22 Meter?) and using a ppO2 setting of 1.2 the decompression profile should not change a lot on the different settings.

diverreb · 10th December 2007, 01:48

Just ran a dive in Deco Planner at 70' for 96 minutes with 38%, which is close to what you did if you ran at a 1.2. Used both the GF's you used.

The deco was 2 minutes at 10/100 and 8 minutes at 25/85. That was with no He.

Add 35% He to that and it's 7 minutes Deco at 10/100 and 20 minutes at 25/85.

Both show the first stop at 30'.

The variance on your handsets doesn't make sense to me.

Richie

**UWSojourner** · 10th December 2007, 02:02

Quote: (Originally Posted by Dsix36)

Primary GF25/85 = FS 20' 4min deco; Secondary GF10/100 FS 50' 38min deco

Something's wrong with the deco value or the inputs. The first stops are plausible, the difference in required deco is not.

***ScubaDadMiami*** · 10th December 2007, 02:27

Oh, I didn't think of something until now. Are you sure you had the secondary on closed circuit (not open circuit)?

***jradomski*** · 10th December 2007, 02:30

Quote: (Originally Posted by Dsix36)

Yesterday I did a dive of 2hr 15min at an average depth of 68'. I have always run my GF at 10/100 and stayed alive (awfully tired and my knees ached that night).
Yesterday I ran my primary GF at 25/85 and my secondary at 10/100. At 1hr 36min into the dive my primary was showing 4min of deco (first stop at 20') and the secondary was showing 38min (first stop at 50').
I set the dil to 21/35 on both handsets. I checked the setting at depth and after the dive. Everthing seems to be right.
Anyway I did the longest deco to be safe (not tired or achy knees last night), but I can't believe that these are right.
I thought that the first number in a GF would put the first stop deeper as the number was smaller. Is this not correct? It seems to me that 10/100 should have had deeper stops and got me out of the water sooner than 25/85.
Any help or advise will be appreciated. I am not a rocket scientist (yet) but I thought that I understood the principals of GF's
Help, I am sooooooo confused.

ignore the TTS numbers, they are wrong but the deco stops are right.. if you add up your actual stops you will see they are usually ALOT shorter than the predicted TTS.. The deeper you need stops the more deco it will show and the worse the TTS calc is.. as you get closer to the surface the TTS gets closer to the real value..

I will try and get around to posting a profile what the HH thinks the ascent is before you start the ascent..

9th December 2007, 13:26	#1 (permalink)
Dsix36 Going Down? Current Rebreather/s: Optima Other Rebreather/s: Join Date: Aug 2007 Location: Deerfield Beach, Florida Posts: 891	setting pri and sec handsets differently??? Yesterday I did a dive of 2hr 15min at an average depth of 68'. I have always run my GF at 10/100 and stayed alive (awfully tired and my knees ached that night). Yesterday I ran my primary GF at 25/85 and my secondary at 10/100. At 1hr 36min into the dive my primary was showing 4min of deco (first stop at 20') and the secondary was showing 38min (first stop at 50'). I set the dil to 21/35 on both handsets. I checked the setting at depth and after the dive. Everthing seems to be right. Anyway I did the longest deco to be safe (not tired or achy knees last night), but I can't believe that these are right. I thought that the first number in a GF would put the first stop deeper as the number was smaller. Is this not correct? It seems to me that 10/100 should have had deeper stops and got me out of the water sooner than 25/85. Any help or advise will be appreciated. I am not a rocket scientist (yet) but I thought that I understood the principals of GF's Help, I am sooooooo confused. __________________ THE MORE THAT I LEARN, THE MORE THAT I STILL NEED TO LEARN!!!!!!
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9th December 2007, 20:57	#2 (permalink)
*ScubaDadMiami* Moderator Current Rebreather/s: Optima Other Rebreather/s: Join Date: Sep 2005 Location: Florida, USA Posts: 1,939	Re: setting pri and sec handsets differently??? I am going to guess that if you did a deeper dive, the pattern you thought would come out would be more like the result you would have gotten. In your particular dive, your decompression obligation was so little that the "10" started you on deeper stops, as it would, but in order to make intermediate stops scaling up to the M-value over the course of the ascent, it ended out adding time to the overall runtime for the dive. __________________ Howard Packer IANTD CCR Instructor Miami Beach, Florida CCRDiveTraining.com Last edited by ScubaDadMiami : 9th December 2007 at 22:14.
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9th December 2007, 21:08	#3 (permalink)
Dsix36 Going Down? Current Rebreather/s: Optima Other Rebreather/s: Join Date: Aug 2007 Location: Deerfield Beach, Florida Posts: 891	Re: setting pri and sec handsets differently??? Nope, no deeper dive. 72' was the max depth for the dive. __________________ THE MORE THAT I LEARN, THE MORE THAT I STILL NEED TO LEARN!!!!!!
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9th December 2007, 21:15	#4 (permalink)
wedivebc FIGJAM Current Rebreather/s: Megalodon Other CCR Other Rebreather/s: Not Bought Yet Inspiration Classic Sport Kiss Other CCR Join Date: Feb 2005 Location: Vancouver Island BC Canada Posts: 1,358	Re: setting pri and sec handsets differently??? Quote: (Originally Posted by Dsix36) Nope, no deeper dive. 72' was the max depth for the dive. I think the point is it's hard to generate accurate "deep stops" on a dive that has (assuming a 1.2 sp) an EAD of 42' or so. I will bet if you try those same settings on a deeper dive you will get the results you expect __________________ Cheers, Dave.... Man is the only animal burdened with the knowledge he will eventually die
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9th December 2007, 22:00	#5 (permalink)
Dsix36 Going Down? Current Rebreather/s: Optima Other Rebreather/s: Join Date: Aug 2007 Location: Deerfield Beach, Florida Posts: 891	Re: setting pri and sec handsets differently??? Quote: (Originally Posted by wedivebc) I think the point is it's hard to generate accurate "deep stops" on a dive that has (assuming a 1.2 sp) an EAD of 42' or so. I will bet if you try those same settings on a deeper dive you will get the results you expect I will definitely be trying just that next weekend. Thanks for the advice. __________________ THE MORE THAT I LEARN, THE MORE THAT I STILL NEED TO LEARN!!!!!!
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9th December 2007, 22:02	#6 (permalink)
gerstl_ossi Custom Title Allowed! Current Rebreather/s: RB80 / Clone Home Build Other Rebreather/s: Not Bought Yet RB80 / Clone Home Build Join Date: Dec 2006 Location: Italy Posts: 280	Re: setting pri and sec handsets differently??? Quote: (Originally Posted by Dsix36) I thought that the first number in a GF would put the first stop deeper as the number was smaller. Is this not correct? It seems to me that 10/100 should have had deeper stops and got me out of the water sooner than 25/85. . Hi, thats right, 10/xx should have a deeper first stop than 25/xx and xx/100 should have shorter decos as xx/85 or xx/70. But as Your diving was not that deep (70" - something like 22 Meter?) and using a ppO2 setting of 1.2 the decompression profile should not change a lot on the different settings.
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10th December 2007, 01:48	#7 (permalink)
diverreb DE/MD/NJ Wreck Diver Current Rebreather/s: Optima Other Rebreather/s: Join Date: Mar 2007 Location: Dover, DE Posts: 517	Re: setting pri and sec handsets differently??? Just ran a dive in Deco Planner at 70' for 96 minutes with 38%, which is close to what you did if you ran at a 1.2. Used both the GF's you used. The deco was 2 minutes at 10/100 and 8 minutes at 25/85. That was with no He. Add 35% He to that and it's 7 minutes Deco at 10/100 and 20 minutes at 25/85. Both show the first stop at 30'. The variance on your handsets doesn't make sense to me. Richie
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10th December 2007, 02:02	#8 (permalink)
UWSojourner Pacific Northwest Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Feb 2005 Location: Portland Oregon Posts: 556	Re: setting pri and sec handsets differently??? Quote: (Originally Posted by Dsix36) Primary GF25/85 = FS 20' 4min deco; Secondary GF10/100 FS 50' 38min deco Something's wrong with the deco value or the inputs. The first stops are plausible, the difference in required deco is not.
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10th December 2007, 02:27	#9 (permalink)
*ScubaDadMiami* Moderator Current Rebreather/s: Optima Other Rebreather/s: Join Date: Sep 2005 Location: Florida, USA Posts: 1,939	Re: setting pri and sec handsets differently??? Oh, I didn't think of something until now. Are you sure you had the secondary on closed circuit (not open circuit)? __________________ Howard Packer IANTD CCR Instructor Miami Beach, Florida CCRDiveTraining.com
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10th December 2007, 02:30	#10 (permalink)
*jradomski* Moderator Current Rebreather/s: Inspiration Classic Sport Kiss Optima rEvo Other CCR Home Build Other Rebreather/s: Inspiration Vision Evolution Megalodon Classic Kiss rEvo Other CCR Home Build Join Date: Mar 2005 Location: "Da" Bronx Posts: 2,817	Re: setting pri and sec handsets differently??? Quote: (Originally Posted by Dsix36) Yesterday I did a dive of 2hr 15min at an average depth of 68'. I have always run my GF at 10/100 and stayed alive (awfully tired and my knees ached that night). Yesterday I ran my primary GF at 25/85 and my secondary at 10/100. At 1hr 36min into the dive my primary was showing 4min of deco (first stop at 20') and the secondary was showing 38min (first stop at 50'). I set the dil to 21/35 on both handsets. I checked the setting at depth and after the dive. Everthing seems to be right. Anyway I did the longest deco to be safe (not tired or achy knees last night), but I can't believe that these are right. I thought that the first number in a GF would put the first stop deeper as the number was smaller. Is this not correct? It seems to me that 10/100 should have had deeper stops and got me out of the water sooner than 25/85. Any help or advise will be appreciated. I am not a rocket scientist (yet) but I thought that I understood the principals of GF's Help, I am sooooooo confused. ignore the TTS numbers, they are wrong but the deco stops are right.. if you add up your actual stops you will see they are usually ALOT shorter than the predicted TTS.. The deeper you need stops the more deco it will show and the worse the TTS calc is.. as you get closer to the surface the TTS gets closer to the real value.. I will try and get around to posting a profile what the HH thinks the ascent is before you start the ascent.. __________________ Joe Radomski CCR Trimix Instructor Trainer ANDI Instructor Trainer Director #10 All posts are personal opinions and DO NOT reflect any affiliated agency unless specifically stated.
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