GF high and NDL

[KenGordon]

Sorry if i use the most conservative setting of ndl 10 min and I exceed it I AM NO IN DECO , I have only triggered a deco alarm by poor institution of a set up configuration. The issue is that if i have 2 puters on my wrists one in liberal and one in conservative. one calls deco and the other is not . which is right? and there is no answer to that. You can not agree to follow both computers directions because they are different. So far you are not providing any useful info. you are only confirming the discrepancies in them. I mentioned tables because you have to have something to be a reference to compare others to. If a table is ok to use in a square dive then doing a square dive with a puter should provide the same results. as settings of conservatism alters those results, then, if the table numbers are valid, the puter results are not but error on the safe side per request by the divers installed configuration. I see a need to to have a 3 min stop for a table because there is no adjustable conservatism mechnism in a chart or table. but it is in a puter, one should not have to have 2 safety mechinisms in play at one time.

If you have two computers and one says you are in deco then you are in deco,

Deco calcs have multiple dimensions and so you cannot be sure of the order in which they will go into deco, it all depends on the profile and how that messes with the modelled compartments.

A table can have conservatism. I can choose to use a deeper depth than my actual plan, or use one time longer. I can even use air tables for Nitrox dives. That is a little bit like how the computers do conservatism in the algorithm.

Next, and a different thing, is good diving practice. A safety stop reduces bubbling later and may thus reduce DCS. It also stops people going directly to the surface and so might reduce the chances of a barotrauma. It does influence peak over saturation but not exactly like using a more conservative setting on the computer.

Why should a computer dive for 27.5m for 16 minutes match a table dive for 30m and 18 minutes? Rounding will make tables different to computers even if they use the same model unless the dive exactly lines up with an exntry in the table.

It sounds like you think that there is optional deco (eg when the 30m dive has an NDL of 10) and compulsory deco (eg 20 minutes). It doesn’t work like that. It is about risk. The 10 dive will be less risky than a 20 minute one which will be less risky than a 25 minute one. Bunt one the day any might, or might not, bend a diver. It is more likely with the 25 minute one but not certain, so why bother with that deco?

If you choose settings then stick with them or choose other ones. The question I sent not “am I in deco?” but “how much am I prepared to skip” and that is very hard to answer on real dives so best avoided.

 

[doctormike]

If you have two computers and one says you are in deco then you are in deco,

Or, you are not in deco! It’s not a binary thing in the grey area, right?

Other than that, an excellent post.

 

[NAM001]

I dont think I will find my answer here. Im not waying I am not finding the answer i WANT to hear Im not hearing an answer.

If 2 computers set up the same and one goes into deco adn the other not.... you process as the worst situation and follow the first computer that goes deco. when you have 2 identical computers set up differently and you get different results it is not an error that you act in the conservative you have deliberately directed the computer to provide 2 different answers. thats not apples to apples. The goal is not to set the computer up to match any preticular table or other computer. the conservative settings should be used and selected for the situation. a 3 min stop is a good form of safety when you use a table that was made with its own constraints like square profile and other things. It would be nice to know what those other things are so you know when you are deviating from the standard that the table was based on. If you are diving with in the standard in the liberal setting and are using the 3 minute stop which is not supposed to be necessary and you instead go to mid conservative setting will that not provide the same safety measure that a 3 min stop does if you dived liberal. What should the guidlines be to say... one should go to a mid or high conservitive setting. IE most liberal should be good for say 90% of 80+F divers. if you dive in colder water like 70f then one should go to mid and if below 55 go to high. There are setting s but no real guidance for when and how to use them the most productive way. The 3 min stop is like a one rule fits all for those not inclined to properly select the correct setting. I have been looking for articles that say what the developement conditions were and the effect of changing those conditions in laymens terms. It is just dead walls or no answers at all. All I have found so far is increase settngss if you are subject to DCS or cold water repeditive dives or repeditive days or fatigued. but they lack measureable definition of what these items are. IE 3 or more repeditive dives in a day. That condition is something one can measure their plans by and correctly set there puter with. With out knowing what those conditions are yo do not know if you have to alter your configuration. The answer of just set it conservative is not good enough. What makes it worse is that you can not find the answers because of fear someone will get hurt if that info was used. The logic of if one step is good then 2 has to be better when in fact perhaps teh second step adds nothing to the safety.

Ill just have to keep on looking to find useful that can give reasonable recommendations. Itas not rocket science if yo can say thetr is a rule of 120 then ther sohould be also rules of thumb to guide computer set ups when it comes to conservative settings.