I died because of my slate - looking for articles/info on slate abbrev.

[battles2a5]

I´m not blackwood (obviously) but once you know your deco obligation it´s not hard at all to distribute that time across stops...you may be a minute or two off from a v-planner plan (for example) but in the grand scheme of things it´s not going to make much of a difference...so you only need to know that staying longer/going deeper means +x mins of deco...

Having said all of that, I still bring a slate and wouldn´t argue that there´s anything wrong with relying on your slate (as long as you then bring a backup schedule...2 of everything you need and so on...)

I don't disagree with what you say about the distribution of deco, etc. etc. But that approach requires (or should anyway) experience to back it up. If you generate a schedule on the fly, there is no other real way to validate the plan without having had experience with those profiles besides blind trust. But the OP is a technical diver in training and does not have the benefit of experience. Ditching the slate in favor of this approach for a new diver would be dangerous if you ask me.

 

[DA Aquamaster]

thanks all. I'm looking for better ways of recording the data. for example, other than for hangs, air breaks etc, do I need elapsed time or only run time?

da_aquamaster - that is exactly the layout I had on my slate. however we got off on the runtime and that is what threw me. adding to the problem was that at the first stop both gasses were within MOD - which may only happen on a training dive. I did a proper NO TOX switch, however to the wrong mix. I had too much info! I've seen other slates that omit some info, and encode other info as symbols - e.g. a horizontal line as a gas switch etc. my tanks are marked left, right, bottom and both side of the top, that wasn't the issue.

I thought about mentioning run time as the number to ignore if the need arises.

I would not sweat the run time too much if you get off after you reach the first deco stop. A slightly longer ascent between stops with a resulting longer runtime is not going to kill you, too rapid an ascent in an effort to get back on the run time will.

If a gas switch takes an extra minute or the 10 ft ascent between stops takes a bit longer than planned, I don't worry about, I just ensure I put in the time at each stop.

Also, some divers will use a more conservative setting on their dive software or computers, while others will use no or very low conservatism settings to ensure they can get out as fast as possible if needed (weather goes down the tubes, etc) and then add some time to the stops at depth, while keeping the general shape of the curve, when there is no need to get out as fast as possible. In that case, the planned run time numbers on the slate become pretty meaningless.

 

[flareless]

.... But the OP is a technical diver in training and does not have the benefit of experience. ....

First, I want to say that as someone who, like the OP, is presently taking the DSAT Tec 1 course, this thread is extremely useful. We're about to begin our in-water dive training and the fact that "most Tec diving deaths are caused by incorrect gas switches" has been driven home. I can pretty much guarantee that I'll be taking my data on my slate, however, memorization will be high on the list of priorities.

I think the above quote is very relevant to the topic though. When I listen to our advanced divers talking about deco dives I'd swear they had part of their brains replaced with dive computers. They quote MODs, PO2S, CNS and OTU data like it was their shoe size. I'm constatnly double checking my tables and formulas before I tend to offer any input into those conversations. I think that having a great deal of experience will definitely help the comfort level and therefore reduce the task loading stress of the situation. Having a lot more comfort will go a long way towards ensuring the procedures are being followed correctly and that the process will be done smoothly and (ultimately) effortlessly (yet without complacence).

As I read through the thread thoughts occur to me; "Maybe I should use colored hoses", "maybe I should have extra tables taped to my bottles" yet each one has had both pluses and minuses pointed out. The fallback seems to be that the information required should be committed to memory . Once again I believe that with experience this should happen almost naturally.

While in my Tec training infancy I plan to; commit to memory as much of the dive plan details as I can, carry laminated dive plan notes (2 sets) as well as contingency plan notes (DecoPlan generates some awesome backup tables). I plan to follow the NO TOX rules to the letter and to observe my team mates to ensure that they are following the protocol and that they are double checking for me (although I'm ultimately responsible for my own butt). Mainly though, I plan to dive a lot with experienced Tec divers and to listen, learn and retain the information they provide.

When I began skydiving years agon (oh no, here he goes again about skydiving) I marvelled as I looked into the sky with the experiened skydivers and listened to them make extensive detailed comments about the jumpers in the air; "it looks like he need the trim adjusted on that chute", "hey, he switched to Vectran lines", "I think that canopy is shot" and wondered to myself "how will I ever be able to do that?". Well, after years in the sport I could spot practically any detail going on in the sky above. I believe (or at least hope) the same thing will become true as applied to gas/depth/time details with respect to Tecnical Diving.

Thanks to everyone for the great information!

 

[Rick Inman]

... "most Tec diving deaths are caused by incorrect gas switches" ...

However, as an additional precaution, I show my teammates my gas selection and they verify I'm on the right gas.

One thing I've seen, when a teammate is confirming the correct bottle, they'll look at the markings (numbers) on the bottle being shown to them and give the OK or not based on that. However, unless you take a moment to really follow the hose with your eyes from the diver's mouth around to the bottle, they could be showing you a different bottle than the one with the reg in their mouth. When I confirm the correct gas switch, I make sure that my teammate is actually breathing from the bottle they are showing me.

 

[Blackwood]

PM sent on the last post directed my way.

they could be showing you a different bottle than the one with the reg in their mouth.

The procedure DA mentioned on page one is good to consider: "and then follow the hose from to the tank to the second stage with your hand to ensure it connects where you think it connects."

If you always maintain contact with the tank (stem, knob, reg, or hose) you've showed, you know you have the right one. If you've shown the right bottle, don't let go. And if you break contact during the switch procedure, re-verify.


I'm going to reiterate that I wasn't telling anyone what they should be doing. If you want to use a slate, use a slate.

That said, a big portion of dive safety and enjoyment is comfort. I think we can all agree that if you aren't comfortable doing a dive, you should not do it. For me, I would not comfortable if I didn't know the nominal schedule as well as I know my own name.

 

[SparticleBrane]

Flareless -- according to your profile you have <50 dives. Is this still correct? Are you really taking a technical course with such little experience?

 

[mark99]

 

[rongoodman]

I'm still a little confused about the mistaken gas switch that "killed" you. Were you below the MOD of the gas you switched to, and if not, how were you "harmed". (I just got lost in the narrative, not trying to be argumentative.)

 

[grazie42]

I don't disagree with what you say about the distribution of deco, etc. etc. But that approach requires (or should anyway) experience to back it up. If you generate a schedule on the fly, there is no other real way to validate the plan without having had experience with those profiles besides blind trust. But the OP is a technical diver in training and does not have the benefit of experience. Ditching the slate in favor of this approach for a new diver would be dangerous if you ask me.

I agree but you also "have to start somewhere" and the beginning is usually a good place...maybe not during the course but pretty soon afterwards "team standards" should be established and comitted to memory, the slate then becomes a backup...until it is, two schedules should be brought on every dive...IMO...

 

[BarryNL]

I did a proper NO TOX switch, however to the wrong mix. I had too much info!

This is one of the weird things with the DSAT course: they seem to want bottle markings with gas mix, max depth, diver name, fill date, filler name, name of fillers pets, weather duing fill, type of analyser used, favourite colour, etc.

The deco bottle needs just the max. depth in great big numbers that everyone can read. The rest of the information is not needed underwater. Then you know that when you get to 21m you switch to the bottle that says "21". When you get to 6m you switch to the bottle that says "6 OXYGEN" (ok, that's extra info).

Of course this all becomes easier if you use - yep, standard gasses. Then you always make your switches at the same depths and have less to remember during the dive.