How much wiggle room?

[Diver0001]

For tech training dives the schedule is the schedule.

This is true. For tech training dives the plan is the plan despite best practices to the contrary. I've personally seen how this philosophy can break down and make a major incident out of a minor occurrence. So have most experienced tech divers. That's the reason we don't see things in black and white.

Learning to approach problems flexibly has a massive added value to the divers' skill set. Teaching people to approach problems inflexibly costs lives.

YMVV.

R..

 

[PfcAJ]

I think you need the *ability* to adhere to a strict schedule. In real life you don't really need to most of the time though.

 

[RJP]

I think you need the *ability* to adhere to a strict schedule. In real life you don't really need to most of the time though.

Ability... and understanding of what the plan means as well as implications of going past/time depth. On dives I've not done before I'll typically run a plan, and a +5min. (On wrecks, depth is usually the sand.) often, knowing what the +5 schedule looks like helps make the decision as to how closely the original plan is adhered to.

 

[Kevrumbo]

Do no more than two deep Tech Dives per day with mandatory decompression profile schedules, and be prepared to extend out your Oxygen Deco Profile Time Schedule (surfacing Gradient Factor of 60 or less) at 6m/20' if you use bottom mixes with high Nitrogen FN2 like Air over several consecutive dive days. Take a day-off to rest & further off-gas inert residual Nitrogen after 4 to 5 consecutive dive days of mandatory Tech Decompression Profiles especially if you use Deep Air for working bottom mix.

 

[_Slacker_]

I think you need the *ability* to adhere to a strict schedule. In real life you don't really need to most of the time though.

The caveat here is that you understand the consequences of deviations. The best way to do that is to begin with a plan. If you dive a shorter time or shallower depth no real issue, but if you stay longer or deeper do you have the reserve gas for it? Do you want to spend that much time hanging on deco? You don't know if you just jump in the water and wing it. At recreational depths things don't progress so rapidly that you can get into too much trouble in a few minutes, but as the depths increase into the tech range, small deviations can make much larger differences.

 

[Nasser]

The gas plan will be the determining factor in all cases. So we'll define the general parameters of the dive and cut a table for that and then also plan for lost gas, deeper/longer etc.. Then dive more freely within the general plan... riding the computer and having the tables as backup. This will give us a framework and reference to work off of and helps to define the outer "red line" limits so to speak. We still dive very much as a team and within very close proximity in case something goes down... but the diving is a little more relaxed.

 

[waterpirate]

Riding the computer is no biggie, if you understand what it is going to tell you ahead of time. I have heard many divers complain on the boat that they wished they could get that minute back. That minute is the minute before your computer rolls over to the next tissue group and you go from a sensible deco time, to one that makes you grimace.

I ride the computer but always have cut tables and rely on RD to make sure that I understand where that moment is on any given dive in the T1 range. For my few forays into T2 I cut the tables and follow the schedule.
YMMV
Eric

 

[ajduplessis]

Ability... and understanding of what the plan means as well as implications of going past/time depth. On dives I've not done before I'll typically run a plan, and a +5min. (On wrecks, depth is usually the sand.) often, knowing what the +5 schedule looks like helps make the decision as to how closely the original plan is adhered to.

Thats what I like about the @+5 function on my Petrel. Its a valueble tool to me.

 

[TSandM]

I suspect part of the reason tech CLASSES are so adamant about the schedule is that, as they increase diver stress with failures, the point at which the diver loses the schedule is the point where the stress has affected their situational awareness to a major degree. The schedule is an easy thing for the instructor to keep pointing the student to, to force the student to expand the envelope of awareness that he or she can handle. IRL, if you spend one minute longer at a stop because you were dealing with something, it's not likely to make a big difference, because if you ran profiles on slightly different gradient factors or with Buhlmann versus V-planner, you'd come up with at least that much variation between the profiles.

A real-life example was one of my first tech dives. We went up to Saanich Inlet to dive the cloud sponges. Planned profile was 120 for 30, and we had O2 for accelerated deco at 20 feet. I planned the dive with that profile, but as it turned out, our average depth was closer to 110, so I adjusted the deco on the fly. We got to the ten foot stop and I signaled for what, if I remember right, was 3 minutes of deco, and Peter looked at his computer and said no, we needed to do TEN. I hated him. The water was 41 degrees and I was freezing my butt off, but according to the rule of "follow the most conservative deco plan" we did those extra 7 minutes. He had his conservativism set higher than normal .

 

[PfcAJ]

I think the discussion on what algorithm or conservatism setting you're using needs to happen before you're in the water.