Contingency Deco Plan
- Thread starter Remy B.
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Yes, that is the cruel part of technical diving, if you get to that point, you have to be cold blooded, but as well your buddy, and it suppose that both of you know and had discussed this at the surface, this is what my instructor had mention in discussion, you need to make a decision and this decision go both ways and this decision shall had been discussed previously and seriously.
Don't become the second victim rule, that has been taught to all of us, of course one never know how the real deal will unfold but, having this discussion in the back of your head may help
I only can plan a dive like that with a contingency that my equipment allow me to do so, there for I believe setting the plan to 30min @ 60m, the rest is in case things go wrong.
AJ
Yes I know there is no guaranty that I will not get a hit, with either contingency profile, GF or VPM, I wrote this many times in the previous posts.
60m for 30min seem like baby dives fro many of you, but that is what I will set as my limit, and train to get to that point and buy what I need to buy to get there, everything beyond that is a bulk of tanks on you the way I see it.
No I'm not contemplating re-breathers can't afford 10000$ to 15000$ in equipment.
Don't become the second victim rule, that has been taught to all of us, of course one never know how the real deal will unfold but, having this discussion in the back of your head may help
I only can plan a dive like that with a contingency that my equipment allow me to do so, there for I believe setting the plan to 30min @ 60m, the rest is in case things go wrong.
AJ
Yes I know there is no guaranty that I will not get a hit, with either contingency profile, GF or VPM, I wrote this many times in the previous posts.
60m for 30min seem like baby dives fro many of you, but that is what I will set as my limit, and train to get to that point and buy what I need to buy to get there, everything beyond that is a bulk of tanks on you the way I see it.
No I'm not contemplating re-breathers can't afford 10000$ to 15000$ in equipment.
The rebreather cost is always overblown. Yeah they have a huge upfront cost. But how much have you spent on all that open circuit gear for deep diving + gas bills? Multiple sets of doubles accumulating, all the deco tanks needed, all the reg sets, the gas bills (I've seen people pulling a trailer filled with tanks for one person if diving a couple day in an area without accessible gas fills) - it adds up.
Yeah rebreathers are more expensive up front but not as astronomically expensive as people make them out to be.
Anyways, I'll resume eating my popcorn
Yeah rebreathers are more expensive up front but not as astronomically expensive as people make them out to be.
Anyways, I'll resume eating my popcorn
Jack Hammer
Contributor
This is really a question I'd expect from some one who us taking or just completed AN/DP, not from some one planning a dive to 60m. Perhaps the internet isn't the best place gain experience. 
Um, I guess my ignorance is showing since i do understand the OP point and agree with some of @tbone1004 points as well. As far as planning beforehand, I guess a few backup tables of incremental deeper / longer would be as far as one could go.
Everyone dives with their "tame" algorithm / GF. However we all know that there is more than one way to skin the cat and sometimes we are on a conservative setting that might be safely made less conservative due to external factors.
As an example: Im diving in nice warm quiet waters so Ive planned a GF of 50/70 and carried sufficient gas for that algorithm etc. I really don't mind spending time at 6m staring at the fishes so all good.
Then, as I switch to the O2, I get stung by a damn jellyfish and my arm is on fire. Now I don't want my padded, extra-conservative deco strategy I want to get out as soon as safely possible.
Or in colder water, I have a drysuit flood and now I want to dive a GFHi of 90 to get out of the cold ASAP. (Hmmm. Or do i want to pad the deco to offset the effects of the cold and dive to a lower GF or until my gas runs out....need to think about this a bit more)
Or Im diving a wreck and my buddy cuts himself on the wreck. Now he is bleeding in the water and the idea of hanging at 6m waiting for the taxman to arrive is somewhat less appealing.
Or it took so long to get my buddy sorted out on the wreck that we have overstayed dramatically and now our gas planning for 50/70 is shot but 50/90 is more doable.
Practically, I dive with 2 computers and one is set to a low conservatism ( GF50/90) for emergency purposes and the primary is set to my planned GF for the day (usually 50/70), if the backup is cleared I know I have the option of getting out earlier if needed. The primary is a Perdix so if my get out of jail computer dies then I can change GF Hi on the fly as needed.
Everyone dives with their "tame" algorithm / GF. However we all know that there is more than one way to skin the cat and sometimes we are on a conservative setting that might be safely made less conservative due to external factors.
As an example: Im diving in nice warm quiet waters so Ive planned a GF of 50/70 and carried sufficient gas for that algorithm etc. I really don't mind spending time at 6m staring at the fishes so all good.
Then, as I switch to the O2, I get stung by a damn jellyfish and my arm is on fire. Now I don't want my padded, extra-conservative deco strategy I want to get out as soon as safely possible.
Or in colder water, I have a drysuit flood and now I want to dive a GFHi of 90 to get out of the cold ASAP. (Hmmm. Or do i want to pad the deco to offset the effects of the cold and dive to a lower GF or until my gas runs out....need to think about this a bit more)
Or Im diving a wreck and my buddy cuts himself on the wreck. Now he is bleeding in the water and the idea of hanging at 6m waiting for the taxman to arrive is somewhat less appealing.
Or it took so long to get my buddy sorted out on the wreck that we have overstayed dramatically and now our gas planning for 50/70 is shot but 50/90 is more doable.
Practically, I dive with 2 computers and one is set to a low conservatism ( GF50/90) for emergency purposes and the primary is set to my planned GF for the day (usually 50/70), if the backup is cleared I know I have the option of getting out earlier if needed. The primary is a Perdix so if my get out of jail computer dies then I can change GF Hi on the fly as needed.
Hey Rainpilot, I always appreciate your insightful posts, but I think I'm going to agree with Ken on this one. Your required deco is your required deco. This is just me, but I tend to be conservative when it comes to deco. Here's what I would do in response to your scenarios:
Suck it up and finish original deco.
I would finish my original deco or stay as long as I thought was actually possible without risking becoming really hypothermic.
Suck it up and finish original deco unless there was the danger of actually passing out from blood loss. In this event, I would probably make the decision to let my buddy ascend while I finish deco at 15'
Just use all of my available gas to do as much of my planned deco as possible. Maybe this would actually get me out of the water on a 50/90 schedule, but changing the algorithm doesn't change your deco physiology or the chances of a hit.
Suck it up and finish original deco.
I would finish my original deco or stay as long as I thought was actually possible without risking becoming really hypothermic.
Suck it up and finish original deco unless there was the danger of actually passing out from blood loss. In this event, I would probably make the decision to let my buddy ascend while I finish deco at 15'
Just use all of my available gas to do as much of my planned deco as possible. Maybe this would actually get me out of the water on a 50/90 schedule, but changing the algorithm doesn't change your deco physiology or the chances of a hit.
packrat12
Contributor
RyanT - What is do you consider your required deco? Is it determined by a GF of 20/70, 30/85, 40/90, something different?? Why is 99/99 not the required deco after all it is the true M-Value line? I use a GF of 30/85. Everyone else does too right? It must be the only one out there..
I think it is proper to say that the 'required deco' is 99/99 for Buhlmann. The GFs are a 'conservative' margin to be determined individually. Why, in an extreme situation, am I going to not take the appropriate risk I decide to get out of the water as quick as I am willing to do? Maybe for some it is 99/99 while others it is 30/85....
@RyanT Ive been called many things, insightful? Them's fighting words!
@packrat12 gets to my point I think. Lets state as a fact we all agree on, that required deco is required deco.
Now that number is an unknown to us. We use GF and fine tune for how we feel post dive, adjust for gas considerations and runtimes etc etc etc. We all have a certain amount of "must-do" deco and some amount of "padding" deco that we do for the wife and kids etc.
What I need is a means of being able to reduce my "padding" in a sensible informed way when circumstances dictate. I learned to dive in Cape Town and watched a friend get eaten 50' from me by a Great White while free diving. When i refer to bleeding being an issue, Im not talking about blood loss from the cut.
I hear people on here (cf. the infamous d**p stops thread) where people talk about "I always used GF XX/90 and had no problems, since I switched to GF XX/70 I feel much less fatigued after a dive" and similar statements. If that diver was in an excrement / ventilator interface scenario would they be justified in switching to GF Hi of 90 to compromise between an emergency situation and a possible DCS hit? I suspect i would feel ok knowing that option was there. Hell, if I am diving 50/70 then I can switch to rec mode on the Perdix and cut down my deco.
Disclaimer: What I don't know about true technical diving / emergency handling would fill several large libraries. I DO know that no-one sucks up a Portuguese Man-o-war sting. Or a stonefish injury. I do have the pain tolerance of a ..... thing with VERY low pain tolerance.
@packrat12 gets to my point I think. Lets state as a fact we all agree on, that required deco is required deco.
Now that number is an unknown to us. We use GF and fine tune for how we feel post dive, adjust for gas considerations and runtimes etc etc etc. We all have a certain amount of "must-do" deco and some amount of "padding" deco that we do for the wife and kids etc.
What I need is a means of being able to reduce my "padding" in a sensible informed way when circumstances dictate. I learned to dive in Cape Town and watched a friend get eaten 50' from me by a Great White while free diving. When i refer to bleeding being an issue, Im not talking about blood loss from the cut.
I hear people on here (cf. the infamous d**p stops thread) where people talk about "I always used GF XX/90 and had no problems, since I switched to GF XX/70 I feel much less fatigued after a dive" and similar statements. If that diver was in an excrement / ventilator interface scenario would they be justified in switching to GF Hi of 90 to compromise between an emergency situation and a possible DCS hit? I suspect i would feel ok knowing that option was there. Hell, if I am diving 50/70 then I can switch to rec mode on the Perdix and cut down my deco.
Disclaimer: What I don't know about true technical diving / emergency handling would fill several large libraries. I DO know that no-one sucks up a Portuguese Man-o-war sting. Or a stonefish injury. I do have the pain tolerance of a ..... thing with VERY low pain tolerance.
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