Why no slates?

[MXGratefulDiver]

DecoPlanner and RD are tools. The real answer is to know when and how to combine them.

Personally, I don't jump in the water without at least an idea of my deco. Often, I'll print multiple tables for different run times at different depths.

Could I formulate a deco schedule that will get me out of the water? Sure. Is that my first line? No.

Back to slates and wetnotes. Writing down your schedule(s) is a great idea. Since the team member calling deco is predetermined (save some issue during the dive), then you don't really need to look at it if you aren't that person. If you want to, great! Its a non-issue. If you want to say something, its ok to bust out the notes. Once again, it doesn't take that long and shouldn't be a problem for you.

Yup ... ratio deco is not a decompression algorithm ... it's a profile shaping tool. Although I use it routinely for dives that require deco profiles, I will still want to run those dive plans on a decompression program to have a basis for comparison. And after you've run the same, or similar, profiles a few times, it gets to the point where you don't need to write down your schedule anyway.

... Bob (Grateful Diver)

 

[nadwidny]

For ocean tech dives you don't know the deco until you've done the dive.

That's nonsense.

We do know general parameters ahead of time (e.g. how much deco time we could accumulate and still have enough gas, the MOD of our backgas, etc.). If your team knows what its doing all that you need to do is signal "average depth" then give a number and everyone pretty much knows the schedule from there.

In the cave you know the average depth ahead of time (not a virgin cave). You know your consumption in psi (seen that anywhere?). You know your turn pressure. You can pretty much figure out your in and out BT based on those 3 values. Compare that time with the MDL time. The time over MDL is deco time. Shape it exponential and then halve the 20+10 time for the O2 benefit.

Sounds like ratio deco which isn't the best solution all the time.

No slate needed or even desired in either case. By those fully trained, Decoplanner is only used for wacky profiles and to run what ifs scenarios.

Guess I'm not fully trained since I use DP for all my dives below 190.

 

[rjack321]

In caves, I use RD to get an idea of the deco, then use DP tables set to my risk tolerances to fine tune it.

FWIW, I was taught in C2 and T1 that RD is intended as an excellent backup tool for determining deco.

Danny seemed to think our deco plans were fine. And we used west coast Joe Talavera 100ft=20min setpoint tables with -20% EAD for the MDL parts and divided by 2 to get the O2 time.

My T1 was in a different era, I don't know what they teach now although I do know shaping the curve is out.

 

[rjack321]

That's nonsense.

plus minus 5 mins makes a huge difference below about 160'. Rather than planning for someting and lining up a zillion contingencies we treat the whole dive like a contingency.

Sounds like ratio deco which isn't the best solution all the time.

Never said it was

Guess I'm not fully trained since I use DP for all my dives below 190.

The VPM and Buhlmann version or just the Buhlmann version?
Shape, time, or both?

I use VPM but only to play around with what ifs. I've never actually dive one of its profiles start to finish unadulterated.

 

[MonkSeal]

... although I do know shaping the curve is out.

No, it's not.

 

[flareless]

I've used both and prefer wet notes. I've had the slate open up in current, get snagged on things I'm passing through and dangle its pencil on the bungee while I tried to nab and reseat it (although this is an entertaining game on a drift dive ).

They are handy for deco tables as they are right out there and easy to read. I tape deco tables to mine.

The really nice thing about wet notes is that the pages go through my laser printer. All my tables are perfectly legible. This is good as my handwriting sucks.

 

[MonkSeal]

This was posted in the general DIR forum, and it is my understanding that non-DIR answers and discussion are okay here. It's the Practitioner's forum where it's restricted to DIR answers only.

I don't know; I'm not mod I guess that discussions are ok, but having advices oposite to DIR practice is not productive. For somebody who's looking for DIR advice or wants to discuss reasoning behind some DIR practice it can be totaly confusing. If non-DIR advices are allowed why to post in DIR forum. I see this as:
a) DIR forum - general discussions about DIR equipment, procedures, reasoning, etc.
b) DIR practitioners - advices on particular situations derived from actual practice
c) any other forum - non-DIR answers acceptable

Deco is always done on the fly? Wow. In Rec Triox, we ran a bunch of profiles through Deco Planner and then added deep stops and O2 window time, so I assumed that at least some DIR divers did that. You can tell I haven't done Tech 1, can't you?

Of course we run profiles through DP (even have DP generated tables in wet notes) and try to get picture of deco in the neighborhood of our dive (+/- depth and time wise). Before the dive we have clear picture what we aim to do. But at the end of the day, the exact amount of deco is decided when deco has been started - which means on-the-fly (it does not mean nescessary that RD is used, while in practice usually is).

 

[RTodd]

Danny seemed to think our deco plans were fine. And we used west coast Joe Talavera 100ft=20min setpoint tables with -20% EAD for the MDL parts and divided by 2 to get the O2 time.

My T1 was in a different era, I don't know what they teach now although I do know shaping the curve is out.

Probably because the dive times get ridiculous in Mexico before deco even matters. RD doesn't work for most cave diving because the times are so long. RD has a fairly narrow time band in which it works. So, it breaks down for most cave dives. I use a bizarro combo of tricks, past experience, etc. But, I generally start with a deco planner table. For longer dives that you don't know the deco in your head, pull the table out of wetnotes. If you will have a scooter with you, one trick is to tuck the tables under an innertube wrapped around the upper part of the scooter after you start deco so you can easily reference it. This is really only helpful for longer exposures. You can do the same thing with a stage but it isn't as convienently accesable. And for most deco even if you glance at your tables it usually isn't complicated enough to need to continue referencing it so you can but the tables back in the wetnotes.

For the orginal question - DIR answer is no wrist slates. Reasons have been given above.

 

[Reg Braithwaite]

For the orginal question - DIR answer is no wrist slates. Reasons have been given above.

Thanks for circling back, I had begun to zone out! (Although I think it's great that the thread went in a new, interesting direction). I doubt anybody cares, but:

1. Wet notes for writing, sharing, and complex things.
2. Write ona piece of Duct tape/gaffer tape if I ever have the urge to want a handy reference on my arm.

 

[cfenton]

No slate needed or even desired in either case. By those fully trained, Decoplanner is only used for wacky profiles and to run what ifs scenarios. Not to generate tables for lamination.

I'm by no means fully trained as I'm only T1. But we were taught to us DP and reshape the profile for deep stops, O2 window, etc. Ratio Deco was strictly taught as a back up tool. And I'm pretty sure I did T1 around the same time as you.

In reality we almost always use Ratio Deco as a primary plan for these shallow deco dives. Probably only because it's quicker and it works.