Suunto Computers - Final Conclusion.

[JohnnyC]

Huh? You do know that if you wait 6 hours your NDL for the next dive's gonna be 4 minutes, and if you wait 6 hours 1 minute it's going to be 8? That's how the model works.

Is yours giving you less NDL after longer SI? Or are you saying Suuntos are bad because that quirky math has too many numbers and stuff?

His point is if you wait 59 minutes it will give you an NDL of 5 minutes, if you wait 61 minutes it will give you an NDL of 20. Obviously I just made those numbers are made up to illustrate his point. Are they exaggerations? Maybe, maybe not. It depends on several factors of which we have a vague idea at best, and at times seems quite arbitrary.

He's trying to illustrate the seemingly arbitrary and proprietary nature of RGBM's penalizations. While the plural of anecdote isn't data, it's pretty well accepted that doing certain things while diving a computer running RGBM will cause the computer to penalize the diver on subsequent dives to a greater degree than other algorithms. SIT's less that one hour are one of those things.

 

[KeithG]

His point is if you wait 59 minutes it will give you an NDL of 5 minutes, if you wait 61 minutes it will give you an NDL of 20. Obviously I just made those numbers are made up to illustrate his point. Are they exaggerations? Maybe, maybe not. It depends on several factors of which we have a vague idea at best, and at times seems quite arbitrary.

He's trying to illustrate the seemingly arbitrary and proprietary nature of RGBM's penalizations. While the plural of anecdote isn't data, it's pretty well accepted that doing certain things while diving a computer running RGBM will cause the computer to penalize the diver on subsequent dives to a greater degree than other algorithms. SIT's less that one hour are one of those things.

The key point here is "penalize" (not calculate).

Like all other computers Suuntos run an algorithm to determine your NDL. The difference is that under somewhat vague circumstances Suunto will then take that nicely calculated NDL and penalize you by arbitrarily reducing the nicely calculated NDL amount by some unknown to us extra penalty amount.

This concept of an extra arbitrary penalty does not exist in other computers. They just run the calculation and give you the expected NDL. This extra penalty behavior has led to the computers being labelled as very conservative - but only by people who incur the penalties.

If you stay away from the Suunto penalty zones then the calculated NDL is predictable and repeatable - and no more conservative than most other computers.

 

[dmaziuk]

He's trying to illustrate the seemingly arbitrary and proprietary nature of RGBM's penalizations.

When I key in 99 my microwave oven runs for 99 seconds. When I key in 100 it runs for 60 seconds. I'm sure that must be Suunto's fault too. Objective reality is largely arbitrary and erratic and makes no bleeping sense, you're complaining about attempts to describe imaginary bubble in theoretical tissue compartments (not to be confused with any actual tissue, living or dead)?

 

[dmaziuk]

This concept of an extra arbitrary penalty does not exist in other computers. They just run the calculation and give you the expected NDL.

BS. Have you run RGBM alongside VPM-B and compared the calculated loading? How about GF, that's not an arbitrary penalty? What, in your opinion, is non-arbitrary about choosing a GF Hi of, say, 80?

That is aside from calculated NDLs being poor measure of anything, and those calculated in plan mode: infinitely more so.

 

[doctormike]

The key point here is "penalize" (not calculate).

You are assuming that there is some sort of precisely calculable "correct" amount of deco for any given dive, and then Suunto arbitrarily adds something to that. This is not how decompression physiology works.

The Petrel comes up with a decompression schedule based on a public domain algorithm, and the inputs are depth, time and mix.

The Suunto comes up with a decompression schedule based on some proprietary unknown algorithm, and the inputs SEEM to be depth, time, mix, sawtooth profile, SI, etc... Of course, no one knows exactly what they are considering, because it is proprietary.

That doesn't change the fact that each computer generates what it's manufacturer (and user, by changing GFs or other settings) feel is a safe compromise between minimizing decompression stress and excessively limiting NDLs (for a recreational dive).

They are BOTH calculating. You are just using the word "penalize" as a pejorative. You could also say that the Petrel "penalizes" you for extra time at depth, or for diving a less than optimal mix at depth.

 

[KenGordon]

If you own a suunto it is very easy to "get evidence" about algorithm quirks. Just check the dive planner.

Do a dive. Wait 59 minutes and check your allowed NDL for the next dive. Wait until 61 minutes of SI and check again. Do this a few times.

Can you tell us what happens please?