TDI Deco/Adv EANx Equipment
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If you don't already have a nice bottom timer, get one that can give you actual average depth on the fly (like the Uwatec bottom timer.) Some bottom timers, like my Suunto D3, only give me average depth once the dive is over.
ucfdiver
Contributor
That data can't be used (accurately) for a dive anyways...
It can be used effectively for decompression calculations. For this particular discussion relating to a TDI advanced nitrox & deco class, it isnt relevant unless you happen to get an instructor who is also GUE or similar who will be including it in the class. Ratio deco and average depth calcs arent standard in the TDI class.
Its not mandatory equipment, but I always recommend a good computer such as a Shearwater. Most of my students end up seeing / using / buying one because they are so easy to use and so obviously beneficial. On the main screen you get your gas mix, your run time, your NDL and deco time at next stop, next stop depth and Time To Surface (based on programmed gas) which is particularly useful. You can see the whole schedule at a glance. A back up is nice too
Then I back all that up with tables and wetnotesAs was rightly mentioned, DIN is obviously standard.
ucfdiver
Contributor
I was referring to the average depth calculator. Obviously the bottom timer works.
Here's what I was referring to (and feel free to correct me if I'm wrong here, I'm bringing this up in the interest of having a good discussion)-
Let's say you're swimming a cave that's 50ft deep and has a jump to a room that drops to 150ft. You spend 10 minutes swimming there @50ft, and 10min admiring the room @150ft, and 10min swimming back, so your average is technically 83ft for 30min.
83ft - 25min VPM+2
Depth Time
83 25
20 3
Custom Multilevel profile (notice it wont even let you ascend to the 50ft swim home without deco)
Depth Time
50 10
150 10
70 1
50 10
20 5
Am I misunderstanding how the uwatech would give you average depth here? From what I understand, for a deep wreck dive where you get down to depth quickly it would work, but for a profile with any major change in depths, it won't work?
Average depth is..... average depth, regardless of the profile.
Just another data point with which to make on-the-fly calculations. My "battlefield" pseudo-math and guesstimations are likely to be less acurate than my bottom timer. So what ever data my bottom timer can give me is useful.
Just another data point with which to make on-the-fly calculations. My "battlefield" pseudo-math and guesstimations are likely to be less acurate than my bottom timer. So what ever data my bottom timer can give me is useful.
ucfdiver
Contributor
Agreed, I just wanted to make sure no one took it as a "computer" that could be used to match up with tables. I could see it being a nice sanity check after a long dive where other tasks might have distracted you.
Not manly enough.
Blackwood
Contributor
No, you understand correctly.
The textbook example is a 'standard' versus 'reverse' profile.
If you drop immediately (say 1 minute descent) to 100 and work your way back to the surface 1 minute every 5 feet, you'll read the same average depth as if you spend 1 minute every 5 feet descending and then make a 1 minute ascent from 100 feet.
It's just that, as Harry suggested, you can't use it blindly.
I run average depth comps in my head and compare them to what my gauge reads. The numbers are usually pretty close, but then more of my dives are relatively square.
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