How you write deco plan on your slate?

[LFMarm]

there seems little evidence of writing down dive plans from my observations - most people carry two computers and if your with a buddy also doing the same profile with 2 computers thats a lot of redundancy in a standard tech dive set up- give me 4 computers over a written dive plan any day

Fully agree. It’s just a very cheap and quick insurance for big dives. I hope to never need it but would suck if it did and I didn’t spend the additional 2 mins

 

[lermontov]

Fully agree. It’s just a very cheap and quick insurance for big dives. I hope to never need it but would suck if it did and I didn’t spend the additional 2 mins

if you lose a computer once in 500 dives the odds of losing both are 1/250000 so unless you've got an analogue depth gauge a written plan is pointless anyway as you dont know your depth ( no doubt someone will tell us they have a special reel with knots in it ) but the odds of losing your and your buddies are so so remote as to be considered nil

 

[b1gcountry]

if you lose a computer once in 500 dives the odds of losing both are 1/250000 so unless you've got an analogue depth gauge a written plan is pointless anyway as you dont know your depth ( no doubt someone will tell us they have a special reel with knots in it ) but the odds of losing your and your buddies are so so remote as to be considered nil

Except you might forget to set your mix properly on the surface, and then you probably forgot to set both computers... or some other issue that affects both computers at once...
I dove tables only, so bringing some along seems like cheap insurance even with 2 computers

 

[doctormike]

if you lose a computer once in 500 dives the odds of losing both are 1/250000 so unless you've got an analogue depth gauge a written plan is pointless anyway as you dont know your depth ( no doubt someone will tell us they have a special reel with knots in it ) but the odds of losing your and your buddies are so so remote as to be considered nil

Yeah, I agree, two computers is better than one and a written plan. I was just saying that a written plan is better than assuming that you will be able to work out your deco requirement in your head in an emergency.

I remember when I first did tech training you needed a bottom timer / depth gauge, but at this point, computers are so cheap that it doesn't make sense to do that anyway.

 

[lermontov]

Yeah, I agree, two computers is better than one and a written plan. I was just saying that a written plan is better than assuming that you will be able to work out your deco requirement in your head in an emergency.

I remember when I first did tech training you needed a bottom timer / depth gauge, but at this point, computers are so cheap that it doesn't make sense to do that anyway.

I think youve hinted at the reason we continue to have a written plan, times have changed and now computers are pretty much standard equipment on technical divers. I carry a written plan -it has on it- Turn pressure, Max bottom time, Max TTS - whatever comes first, all based on the dive plan and gas/BO im carrying.

 

[Wibble]

What is the purpose of a written plan?

In the beginning, the written plan is to ensure the novice student understands the planning process. It enables the instructor and students to prove their workings and that they’ve considered all factors (depth(s), gases, decompression algorithm, decompression settings/gradient factors, SAC, gas volumes…). It is also an excellent teaching tool to prove the student can plan a dive and dive the plan.

After a few dives, the planning process is understood. The inexperienced diver has proved the planning process and can move on to using practical techniques and away from the time-consuming manual training techniques; think using a calculator for long division, rather than writing it down.

Also, after a few decompression dives, you will have learned the "pattern" of a dive: how much and what types of gas you need, how much you use, how long you can stay at depth, redundancy, typical decompression stop times, how you feel after the dive…

Then as you’ve done hundreds of decompression dives, you know how much you rely upon your computers. If doing a decompression dive with more than a few minutes of decompression you are utterly reliant upon a dive computer. OR you need a depth gauge AND timer, in other words you need another computer.

In summary, with increasing experience writing the plan on a slate/wetnotes is a pointless exercise as you need a computer to run the timings anyway. A pre-written slate usurps the core purpose of a computer — to accurately monitor your personal depth and time and accurately calculate your specific decompression requirements -- how can you possibly know in advance what the bottom profile is, what the scars look like, what part of the wreck you're diving around?

Slate planning is good for learning. Slates are impractical and inaccurate for actually running a dive where computers provide superior accuracy, reliability and utility.




...
As an aside, was diving a ~60m/200ft wreck the other day and jumped in with another diver. We ran around on the wreck until the computer's TTS said 90 minutes (at about 40 mins runtime) and began the ascent together up the lazy shot line. We stuck together during the deeper stops, me waiting for his stop to clear and ascending to the next 3m/10ft stop. Once up to the 6m/20ft trapeze there were another 4 divers on/around the bar. I was diving with three computers (Nerd, Petrel and Perdix). The other guy diving with one computer and a bottom timer (and had the ratio deco training to manually calculate the stops) — the first time I’ve seen a bottom timer in many years. Most others had at least two computers. Not a single planning slate in use by anyone.

 

[doctormike]

I think youve hinted at the reason we continue to have a written plan, times have changed and now computers are pretty much standard equipment on technical divers. I carry a written plan -it has on it- Turn pressure, Max bottom time, Max TTS - whatever comes first, all based on the dive plan and gas/BO im carrying.

Yeah, but now that I think of it, since I dive with two computers I'm not sure I really DO need a written deco plan. What you are describing is something different - I think that the discussion above was about a written ascent plan.

I guess a written plan with your turn pressure or maximum bottom time would be a helpful reminder for dive planning, but it's not really the same as a backup to your electronics.

 

[b1gcountry]

Meh...I like writing things down. Bottom timers are simple and cheap, and I've never had one fail in water. My DC has run out of juice twice, plus I forgot to set it for my mix once.

Working through the plan with your team before there dive is also important. It's hard to miss the details when you write them down. The more dives I did (often the same people on the same wrecks), the more the plans blended together.

Do what works for you, but dive planning is not just for beginners, and you should be careful not to lay it aside just to feed your ego.

 

[doctormike]

Slate planning is good for learning. Slates are impractical and inaccurate for actually running a dive where computers provide superior accuracy, reliability and utility.

I don't think anyone was suggesting using a written plan instead of a computer by choice. I think that the question was - is it worthwhile to write down your ascent plan in case your electronics fail. Now there are a lot of issues there, such as the fact that many tech divers have two decompression computers, and of course the issue of actually running stops with a total failure of your time/depth measuring devices. But unless you are running a known, square profile, I think that most people agree that the accuracy and decompression advantage of a DC are worthwhile..

 

[Celt]

Computers can’t predict conditions or what a diver gets up to during a dive. Recently I spent 15 minutes cutting the bolts on a port hole at 67m, and sending it up to the boatman, so I did the stops for a longer bottom time. A computer couldn’t know that. If you lowered a computer into the water and brought it back at 30fpm it would record a dive, no need for a diver.
P.S. what is a dive pattern? Complacency!