Contingency Deco Plan

[Remy B.]

What is your criteria on a Contingency Deco plan and do you take in account to Change a Deco Algorithm when doing so ? ( more aggressive is you can called like that )

 

[Tug]

I don't, I just do additional time and additional depth depending on the details of the dive. One of the benefits to Shearwater computers is that you can adjust the GF's mid dive.

 

[tbone1004]

major gas failures or something else that requires you to book it out of the water for some reason, and in that case I will adjust the GF high on my Shearwater from the 80 it normally lives at up to 95-99 if I really need to get out. Very few reasons that that would happen, usually medical.

 

[PfcAJ]

Bring enough reserve gas and you don't have to adjust your conservatism to complete your deco.

 

[tbone1004]

doesn't help if you have something like a valve failure where you can't access said tank though. extraordinarily rare, not something we ever plan on, but the possibility is there. The real one is some sort of medical issue where you need to get out of the water asap.

 

[PfcAJ]

doesn't help if you have something like a valve failure where you can't access said tank though. extraordinarily rare, not something we ever plan on, but the possibility is there. The real one is some sort of medical issue where you need to get out of the water asap.

Your buddy needs to have enough reserve too, and part of the purpose is to be able to share the deco gas.

 

[KenGordon]

What is your criteria on a Contingency Deco plan and do you take in account to Change a Deco Algorithm when doing so ? ( more aggressive is you can called like that )

Your lost gas plan ought to work. By that I mean you ought to be able to lose a deco gas and still get out having done enough deco. So if you have a single deco gas you need either to plan to be able to do the deco on back gas or on your buddy's deco gas once he is finished with it. Either way you will both need enough gas. Would you be pleased by a buddy that had a problem and had planned to force you to cut short your deco?

Some people do plan more aggressive worst case deco for bailing out on a rebreather in the case of a co2 hit. However that is because they also have to plan (guess) very high gas consumption rates and have to compromise on how much gas can be carried.

 

[lermontov]

are you indicating no deco bottle so only gas on you back? if so as above replied buddy has my back up or I do have a prearranged signal with my smb and a tag to indicate to surface crew to lower more gas if in extremis

 

[tbone1004]

Your buddy needs to have enough reserve too, and part of the purpose is to be able to share the deco gas.

so you're telling me that you carry 2x the maximum deco gas with two second stages on all of your deco bottles, or you plan to buddy breathe for multiple hours? That's not practical... we plan for very conservative deco with a gf high of 70, much lower than what you guys typically cut *which IIRC is around 85*.
If we lose a deco gas, while we will have enough in backgas reserves for backgas deco, we may very likely increase that GF high to 90 to get out quicker and just take it very easy at the surface and get to the reserve O2 bottles up there for 10-15 minutes before we haul gear out. Odds are extremely unlikely that you're going to have a valve failure, but it's possible and I'm not buddy breathing for any length of time

 

[RyanT]

I plan to carry enough reserve for myself plus a buddy diving a + 5' / 5 min profile without changing my GF. For some open water divers where staging bottles isn't an option, carrying this kind of reserve could become difficult. For the kind of light tech diving I do, carrying these reserves is easily done.