Ross please ...
Successful outcome is a prerequisite see wiki:
Efficiency is the (often measurable) ability to avoid wasting materials, energy, efforts, money, and time in doing something or in producing a desired result. In a more general sense, it is the ability to do things well, successfully, and without waste.[1][2][3][4][5] In more mathematical or scientific terms, it is a measure of the extent to which input is well used for an intended task or function (output). It often specifically comprises the capability of a specific application of effort to produce a specific outcome with a minimum amount or quantity of waste, expense, or unnecessary effort.
In our case the resource is deco time and the money to keep the surface support team at sea.
What they did at NEDU was assessing how many people would get bent distributing the available and fixed deco time in deeper or shallower stops. They kept bending people untill there was statistica significance. They stopped early because they were bending many more divers with one distribution than the other.
The deeper stops showed being less efficient.
Therefore at same deco time less safe. Safety intended as the probability of getting bent.
[my conclusion]
a deeper start of deco as prescribed by VPM requires me to increase the shallower stop time beyond what VPM would require, in order to achieve the same probability of getting bent.
Hi Fabio,
Decompression is in the field of physics. Efficiency in physics, is the measure of energy to achieve a result. In the case of decompression MODELS, the purpose is to return to surface safely in the shortest time. Therefore efficiency in decompression, is least time to achieve a safe ascent.
DCS rates is measured as risk probabilities, or actual result percentages, but not "efficiency".
If you guys want to abuse the proper science terms, then go ahead... why not.... add it to the list of abuses and distortions used to prop up this fallacy and attacks on VPM-B.
These guys are not comparing efficiency. They have two safe ascents, and trying to judge one better than the other, on some internal dimension..... with no valid method to judge it.
The nedu did not test deep stops.... repeat ... no amount of opinion will change that fact. The nedu tested two long shallow ascents against thermal stress... Please do not try to imply its related to deep stop, or tech practices, see: post #116
The actual nedu result showed us one thing.... models should follow the gas kinetic rules. All your / our models and dive computers, already follow gas kinetic rules: ZHL, VPM-B, etc. Those models already have the correct amount of deep-shallow balance built in... (note: all deco computers have the same kinds of gas kinetic formula too). Nothing is broken, nothing needs fixing.
If you don't agree, then show why ALL existing gas kinetic formula is wrong. You cannot isolate VPM-B and pretend all else is OK.
****
As I have said... these guys keep confusing themselves with the GF fiddling.... chasing their own tail. They create some exaggerated ascent on GF, and imagine it's an original perfect ascent. They forget that the GF profile is a made up one...
One could keep repeating this to process comparing two other GF profiles, and will always think one is better.... because the method always favors the shallow one. Eventually it will get to profiles like 150/20, and still think your ahead... the test is open ended and biased.
There is no proven method to cross compare different profile types.
***************
These guys are not interested in "efficiency", because they are NOT aiming to go fast. If they were, they would be using real ZHL, with no added GF, and be happy doing it..... any takers???
The current trend is to go longer for reasons of extra layers of safety.... i.e. in-efficient use of time.
.
Last edited: