Differences Between UTD and GUE

[mikemill]

There is a particular thread which compares UTD training versus TDI that I found extremely interesting. I recommend anyone interested go check that out.

Link?

 

[radagalf]

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[rjack321]

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Register and be an instructor from any agency.

 

[Rainer]

John, I know you said you averaged 130' for this dive. What was your max depth and how long were you below 130'? I personally place the MOD for 25/25 at 130', and if I know I'm going to be at that depth for most of the dive (or anything deeper), I switch to 21/35 or 18/45, and more importantly, add 50% to take care of the fast tissues (start the deco deeper).

Had you guys had any problems on your other past UTD T1 dives at this depth/exposure?

 

[rjack321]

I don't use a gauge to calculate my average depth. I agree, though, that the average should start on the bottom (ignoring the descent) to remain conservative. Lingering shallow and trying to average that portion into the entire dive could lead, as you note, to a shallower average if you're not careful.

Yeah averaging deep moving towards shallow is fine (we do this all the time, "dragging" a 120ft max up to a 100 or 90ft average)

Having a bunch of time shallow then a deep spike is not a good way to create a shallower than max depth average. When we are forced to do this we use something very close to max depth in calculating deco (I think this has happened only a few times)

Discussion and coarse mathematical/software demo of the concept here

John, I know you said you averaged 130' for this dive. What was your max depth and how long were you below 130'? I personally place the MOD for 25/25 at 130', and if I know I'm going to be at that depth for most of the dive (or anything deeper), I switch to 21/35 or 18/45, and more importantly, add 50% to take care of the fast tissues (start the deco deeper).

Had you guys had any problems on your other past UTD T1 dives at this depth/exposure?

Agree, if I am planning on 131ft+ on go with 21/35. I have momentarily dipped to 135ft on 25/25 but that's mostly a consequence of scootering and overshooting depth a smidge. For us, 25/25 is a 95-125 kinda plan gas.

 

[lamont]

At least UTD *has* an algorithm for O2 dives (a huge GUE weakness, IMO). For these shallow (<120') dives, most GUE people I know are simply doing time over NDL, half credit for O2 + extra five min up on the O2 (the back gas deco up to 20' is done differently by different teams; so much for uniformity...).

I think the GUE algorithm for O2 dives (and altitude diving) is to understand how the T1 RD algorithm was 'discovered' and to sit down with decoplanner/v-planner/etc and to figure out those rules. The message I got was that the GUE approach to decompression planning is not proscriptive (and while this may sound like "personal preference", in this circumstance it makes sense since decompression inherently has a component of individual variability in physiology).

 

[lamont]

Yeah averaging deep moving towards shallow is fine (we do this all the time, "dragging" a 120ft max up to a 100 or 90ft average)

Having a bunch of time shallow then a deep spike is not a good way to create a shallower than max depth average. When we are forced to do this we use something very close to max depth in calculating deco (I think this has happened only a few times)

I've done this a bunch, with 120 foot spikes below the I-beams before surfacing on a dive that was averaging closer to 100 foot.

The spike at the end is only going to have time to affect fast tissue loading and you can compensate by starting deep stops like you were on a 120 foot dive, while doing O2 deco like you were on a 100 foot dive.

 

[Blackwood]

Yeah averaging deep moving towards shallow is fine (we do this all the time, "dragging" a 120ft max up to a 100 or 90ft average)

Having a bunch of time shallow then a deep spike is not a good way to create a shallower than max depth average. When we are forced to do this we use something very close to max depth in calculating deco (I think this has happened only a few times)

I wonder if you couldn't treat it as two dives. Figure the obligation for the deep portion/BT, clear that (it shouldn't be much given the bounce), and also clear the obligation for the shallower portion/BT.

 

[boulderjohn]

Sorry for the delay--I have been offline. We had in very brief initial depth for only a minute to clear a ledge we did not expect to find, and then we were at about 150 for a while, then ascended to about 120 to complete the dive. I did take the average from the BT, including the descent (which was rapid). I can't give the exact figures--I am out of the country doing this from memory.

This was our third day of diving similar profiles. On the previous days, we did some very shallow dives (like 30-50 feet afterwards), and on the last day we only did the one dive.

My friend had a third day of treatment and is doing very well now. His doctor was very adamant about the altitude factor. He got a major lecture about it.

I would be very interested in learning how GUE/UTD determined it is not a factor.

 

[M_Bipartitus]

...
I would be very interested in learning how GUE/UTD determined it is not a factor.

I suspect it wasn't a serious concern to them as the main characters do not live in areas near altitude diving and altitude sites are not popular destinations.