deco plan when running semiclosed

viscya · 14th June 2007, 14:21

FWIW,

Our TDI Kiss air dil class (mod 1 maybe) was expressly NO deco. SCR was taught/practiced extensively based on failure mode (not just last ditch). The rule was no SCR above 30 ft.

Mod 3 covered Deco on SCR very well. Much as DrMike described.

prharris · 14th June 2007, 14:32

Quote: (Originally Posted by viscya)

Our TDI Kiss air dil class (mod 1 maybe) was expressly NO deco. SCR was taught/practiced extensively based on failure mode (not just last ditch). The rule was no SCR above 30 ft.

Ours was the same with IANTD. I had the same instructor as Fin, and although we covered semi-closed from the POV of how to achieve it and practiced it, deco was not touched as the couse is a no deco course.

r
P

Drmike · 14th June 2007, 14:36

The original poster was asking about deco dives - so whats more relavant is wether or not SCR deco calcs are taught on a a ccr deco courses (Mod2, Normoxic or Mod3 hypoxic)

Mark Chase · 14th June 2007, 16:05

Quote: (Originally Posted by Drmike)

who was your instructor?

I would have assumed this was certainly part of any Rebreather class sylabuss???

You didnt practice running semniclosed on your course?
Instructor didnt get you to look at the effective PO2 drops?

Switch vr3 to OC mode and knock back the FO2 a tad. How much to knock it back depends largely on freq of venting you use and can be determined experimentally with a working ppo2 display

Deco is Mod2 or Mod3 not Mod1 and the question was on deco. We were taught Semiclosed on Mod1 but nothing on the resulting pp02 drop or its affect on deco. We did this in Mod 3. I had OC deco procedures already so didn't do Mod2 (hardly any one does it seems)

ATB

Mark Chase

Drmike · 14th June 2007, 16:06

Quote: (Originally Posted by Mark Chase)

Deco is Mod2 or Mod3 not Mod1 and the question was on deco. We were taught Semiclosed on Mod1 but nothing on the resulting pp02 drop or its affect on deco. We did this in Mod 3. I had OC deco procedures already so didn't do Mod2 (hardly any one does it seems)

ATB

Mark Chase

yes we know that its been covered already

Mark Chase · 14th June 2007, 16:20

Quote: (Originally Posted by Drmike)

yes we know that its been covered already

Sorry my mistake, responding to page 1 without reading page 2.

If i remember rightly Mo1 one was all about, if in doubt go OC?

Back on topic a bit:

Has anyone tried a Semiclosed deco from depth? I had a crack on 90mins of deco from 60m. I was in a sorry state by the end with a head ache a sore throut and a very sore nose. I gave up on the 9m stop with about about 45mins to go. I have never tried it since and now prefer to carry a shed load of OC rather than consider semi closed as an option.

I did the ascent using four breaths to a flush and dropped that to three then two in the end. I found it hard work

As a deco plan I did the ascent 2% under mix on a VR3 so the 18/45 was treated as 16/45 for the profile.

dantheman · 15th June 2007, 01:57

Quote: (Originally Posted by Drmike)

The original poster was asking about deco dives - so whats more relavant is wether or not SCR deco calcs are taught on a a ccr deco courses (Mod2, Normoxic or Mod3 hypoxic)

(Intending to state facts and not get personal or cause conflict)

Yes, but it was you who brought Mod 1 into the discussion . . .

--dan

OceanOpportunity · 15th June 2007, 02:04

while I hate these online pissing matches, I think that DrMike's reference to Mod1 came from an assumption that the original poster should have received this scr bailout training in Mod1. Doing a little reading between the lines, it seems that the poster may not have completed any mod2 or mod3 level training, just 'mod1' with Leon, and posted a simple inquiry on how to address scr bailout deco calculations.

for all intents and purposes, diving beyond a mod1 level of training without being trained probably isnt the best of ideas. For sake of answering the original question...if incurring a deco obligation of more time than can be adequately accounted for with a controlled scr ascent followed by OC decompression with what you are carrying, then its time to rethink the requirements for the dive..be it more OC, more training in scr bailout, or a computer configuration that sniffs the gas while in scr

tecdivertraining · 15th June 2007, 02:22

Quote: (Originally Posted by Drmike)

SCR as a bailout technique is taught and is part of the standards. The question I guess is is the method of how to determine SCR deco part of the standards?

if it isnt then IMO it should be - And if your right then thanks for correcting me without bringing conflict and deriding me

Mike I tend to agree with you that SCR mode should be covered more in-depth.

My thinking on this is Mod 1 divers are usually certified to dive to around 40m.

So here is the scenario:

A diver plans a dive to 40m for 25min resulting in 10 min limited deco obligation (planed using v-planner using my personal config) if at the last minute of the dive they had to bailout that would result in an increase of runtime from 40min to 73 min. quite a big jump considering the amount of bailout gas some dives choose to carry and the stress that could be encountered. My personal requirements would call for around a 1000 liters of gas to complete that deco, that’s assuming its not a CO2 issue.

So introducing SCR in this case could avoid a diver surfacing and missing all that required deco due to inefficient gas planning. Some of the divers I have had the pleasure of diving with have never even considered this eventuality and would have been faced with lengthy deco obligations with no reel understanding of decompression diving techniques.

A more in-depth discussion should at least take place during the academic session of mod 1 training even if the diver is far away from making this dive having just passed their course. soon they may be thinking about hitting these depth without considering the bailout gas requirements.

Just my two cents worth.

dantheman · 15th June 2007, 02:37

Quote: (Originally Posted by OceanOpportunity)

Doing a little reading between the lines, it seems that the poster may not have completed any mod2 or mod3 level training, just 'mod1' with Leon, ...

Nope. Different people.

I agreed with nearly everything else you posted, tho.
(especially the summary of why a mod 1 diver would go SCR).

--dan

14th June 2007, 14:21	#21 (permalink)
viscya Wrecking Crew Current Rebreather/s: Classic Kiss Other Rebreather/s: Join Date: Oct 2005 Location: Marlton New Jersey Posts: 140	Re: deco plan when running semiclosed FWIW, Our TDI Kiss air dil class (mod 1 maybe) was expressly NO deco. SCR was taught/practiced extensively based on failure mode (not just last ditch). The rule was no SCR above 30 ft. Mod 3 covered Deco on SCR very well. Much as DrMike described. __________________ "There is nothing majestic or dignified about being left to silently rot and collapse under heaps of old fishing net forgotten and unappreciated in dark and unvisited waters." DrMike
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14th June 2007, 14:32	#22 (permalink)
prharris CK #146 and Shearwater Current Rebreather/s: Classic Kiss Other Rebreather/s: Join Date: Feb 2005 Location: Plymouth Posts: 106	Re: deco plan when running semiclosed Quote: (Originally Posted by viscya) Our TDI Kiss air dil class (mod 1 maybe) was expressly NO deco. SCR was taught/practiced extensively based on failure mode (not just last ditch). The rule was no SCR above 30 ft. Ours was the same with IANTD. I had the same instructor as Fin, and although we covered semi-closed from the POV of how to achieve it and practiced it, deco was not touched as the couse is a no deco course. r P
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14th June 2007, 14:36	#23 (permalink)
Drmike Custom Title Allowed! Current Rebreather/s: MK 15.X Ouroboros Other CCR Home Build Other Rebreather/s: Inspiration Classic Other CCR Home Build Join Date: Feb 2005 Posts: 3,128	Re: deco plan when running semiclosed The original poster was asking about deco dives - so whats more relavant is wether or not SCR deco calcs are taught on a a ccr deco courses (Mod2, Normoxic or Mod3 hypoxic) __________________ Get a girlfriend you sad twat - a Rebreather is an unfaithful mistress - dont blind yourself to her faults just because she goes down on you
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14th June 2007, 16:05	#24 (permalink)
Mark Chase I go down for ages Current Rebreather/s: Classic Kiss Other Rebreather/s: Inspiration Classic Join Date: Jan 2005 Location: Kent Posts: 2,540	Re: deco plan when running semiclosed Quote: (Originally Posted by Drmike) who was your instructor? I would have assumed this was certainly part of any Rebreather class sylabuss??? You didnt practice running semniclosed on your course? Instructor didnt get you to look at the effective PO2 drops? Switch vr3 to OC mode and knock back the FO2 a tad. How much to knock it back depends largely on freq of venting you use and can be determined experimentally with a working ppo2 display Deco is Mod2 or Mod3 not Mod1 and the question was on deco. We were taught Semiclosed on Mod1 but nothing on the resulting pp02 drop or its affect on deco. We did this in Mod 3. I had OC deco procedures already so didn't do Mod2 (hardly any one does it seems) ATB Mark Chase __________________ Is it supposed to make that noise ? I took my unit to the dive shop and demanded they bolt on every thing that would fit. Join my elite diving teem and get a Tshirt "Doing It Chasey"Hammerhead Eccr Advanced Diving System
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14th June 2007, 16:06	#25 (permalink)
Drmike Custom Title Allowed! Current Rebreather/s: MK 15.X Ouroboros Other CCR Home Build Other Rebreather/s: Inspiration Classic Other CCR Home Build Join Date: Feb 2005 Posts: 3,128	Re: deco plan when running semiclosed Quote: (Originally Posted by Mark Chase) Deco is Mod2 or Mod3 not Mod1 and the question was on deco. We were taught Semiclosed on Mod1 but nothing on the resulting pp02 drop or its affect on deco. We did this in Mod 3. I had OC deco procedures already so didn't do Mod2 (hardly any one does it seems) ATB Mark Chase yes we know that its been covered already __________________ Get a girlfriend you sad twat - a Rebreather is an unfaithful mistress - dont blind yourself to her faults just because she goes down on you
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14th June 2007, 16:20	#26 (permalink)
Mark Chase I go down for ages Current Rebreather/s: Classic Kiss Other Rebreather/s: Inspiration Classic Join Date: Jan 2005 Location: Kent Posts: 2,540	Re: deco plan when running semiclosed Quote: (Originally Posted by Drmike) yes we know that its been covered already Sorry my mistake, responding to page 1 without reading page 2. If i remember rightly Mo1 one was all about, if in doubt go OC? Back on topic a bit: Has anyone tried a Semiclosed deco from depth? I had a crack on 90mins of deco from 60m. I was in a sorry state by the end with a head ache a sore throut and a very sore nose. I gave up on the 9m stop with about about 45mins to go. I have never tried it since and now prefer to carry a shed load of OC rather than consider semi closed as an option. I did the ascent using four breaths to a flush and dropped that to three then two in the end. I found it hard work As a deco plan I did the ascent 2% under mix on a VR3 so the 18/45 was treated as 16/45 for the profile. __________________ Is it supposed to make that noise ? I took my unit to the dive shop and demanded they bolt on every thing that would fit. Join my elite diving teem and get a Tshirt "Doing It Chasey"Hammerhead Eccr Advanced Diving System
(Online)

15th June 2007, 01:57	#27 (permalink)
dantheman Emoticonoclast Current Rebreather/s: Sport Kiss rEvo Other Rebreather/s: Classic Kiss rEvo Join Date: May 2005 Location: NorthEast USA Posts: 393	Re: deco plan when running semiclosed Quote: (Originally Posted by Drmike) The original poster was asking about deco dives - so whats more relavant is wether or not SCR deco calcs are taught on a a ccr deco courses (Mod2, Normoxic or Mod3 hypoxic) (Intending to state facts and not get personal or cause conflict) Yes, but it was you who brought Mod 1 into the discussion . . . --dan
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15th June 2007, 02:04	#28 (permalink)
OceanOpportunity for a world of water Current Rebreather/s: Other CCR Dolphin Home Build Other Rebreather/s: Not Bought Yet Inspiration Classic Other CCR Dolphin Home Build Join Date: Nov 2006 Location: Providence, RI USA Posts: 517	Re: deco plan when running semiclosed while I hate these online pissing matches, I think that DrMike's reference to Mod1 came from an assumption that the original poster should have received this scr bailout training in Mod1. Doing a little reading between the lines, it seems that the poster may not have completed any mod2 or mod3 level training, just 'mod1' with Leon, and posted a simple inquiry on how to address scr bailout deco calculations. for all intents and purposes, diving beyond a mod1 level of training without being trained probably isnt the best of ideas. For sake of answering the original question...if incurring a deco obligation of more time than can be adequately accounted for with a controlled scr ascent followed by OC decompression with what you are carrying, then its time to rethink the requirements for the dive..be it more OC, more training in scr bailout, or a computer configuration that sniffs the gas while in scr __________________ Michael Lombardi Oceans of Opportunity www.oceanopportunity.com Elected Director, Society for Human Performance in Extreme Environments MN'07, The Explorers Club Project Manager, Diving a Dream
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15th June 2007, 02:22	#29 (permalink)
tecdivertraining RebreatherWorld Sponsor Current Rebreather/s: Inspiration Classic Inspiration Vision Evolution Megalodon Ouroboros Dolphin Other Rebreather/s: Not Bought Yet Dolphin Join Date: May 2005 Location: Phuket, Thailand Posts: 421	Re: deco plan when running semiclosed Quote: (Originally Posted by Drmike) SCR as a bailout technique is taught and is part of the standards. The question I guess is is the method of how to determine SCR deco part of the standards? if it isnt then IMO it should be - And if your right then thanks for correcting me without bringing conflict and deriding me Mike I tend to agree with you that SCR mode should be covered more in-depth. My thinking on this is Mod 1 divers are usually certified to dive to around 40m. So here is the scenario: A diver plans a dive to 40m for 25min resulting in 10 min limited deco obligation (planed using v-planner using my personal config) if at the last minute of the dive they had to bailout that would result in an increase of runtime from 40min to 73 min. quite a big jump considering the amount of bailout gas some dives choose to carry and the stress that could be encountered. My personal requirements would call for around a 1000 liters of gas to complete that deco, that’s assuming its not a CO2 issue. So introducing SCR in this case could avoid a diver surfacing and missing all that required deco due to inefficient gas planning. Some of the divers I have had the pleasure of diving with have never even considered this eventuality and would have been faced with lengthy deco obligations with no reel understanding of decompression diving techniques. A more in-depth discussion should at least take place during the academic session of mod 1 training even if the diver is far away from making this dive having just passed their course. soon they may be thinking about hitting these depth without considering the bailout gas requirements. Just my two cents worth. __________________ Mathew Partridge Technical Director Pro-Tech Dive College www.protechdivers.com www.tech-ccr.com
(Online)

15th June 2007, 02:37	#30 (permalink)
dantheman Emoticonoclast Current Rebreather/s: Sport Kiss rEvo Other Rebreather/s: Classic Kiss rEvo Join Date: May 2005 Location: NorthEast USA Posts: 393	Re: deco plan when running semiclosed Quote: (Originally Posted by OceanOpportunity) Doing a little reading between the lines, it seems that the poster may not have completed any mod2 or mod3 level training, just 'mod1' with Leon, ... Nope. Different people. I agreed with nearly everything else you posted, tho. (especially the summary of why a mod 1 diver would go SCR). --dan
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