average depth tables???

[Mal Bridgeman]

Originally Posted by liamm

Is there a course that covers ratio deco or is this the realm of GUE?

It's not exclusive to GUE but Tech 1 would be where it's covered.

You might like to read this from Garf.....you'll possibly conclude that it's also, quite straight forward.

I'll caveat that with the rider that this information does not stand in isolation but is part of a more textured picture which is not covered in Garf's description.

HTH
Mal

[Mark Chase]

Originally Posted by Garf

I thought you used computers Mark. Do they calculate deco based on the max depth then. I thought that computers monitor what you are actually doing with regards to exposure and adjust the decompression obligation accordingly.

With ratio deco, what we do is monitor what we are actually doing with regards to exposure and reduce the deco accordingly.

Granted we don't do it as efficiently as computers, but they are checking your depth and adjusting from instant to instant, whereas we are doing it every few minutes.

so you can look at both computers and ratio deco as a means of tracking what you are doing more efficiently than a table, which has to assume a constant max depth. Or you can look at them both as shaving deco, if this is your preference.

I use one computer and i use ratio deco to confirm it and just in case it breaks.

Tables are a fixed safety setting. In order to make them more aggressive you have to say you did a shallower dive. To make them less aggressive you say you did a deeper dive.

On a computer you program in your preferred safety settings before you get in the water. I don't run my computer on 100/100GF If i did it would give me something close to Buhlman Tables. I run it on 10/90 to add conservatism and then pad out the shallow stops as required on the day.

FACT: A straight Buhlman table profile based on max depth is less aggressive than a straight Buhlman profile based on avg depth.

FACT: A GUE profile based on max depth is less aggressive than a GUE profile based on average depth.

Do what ever works for you, but don't pretend by using avg depth your not adding a level of aggression.

ATB

Mark

[Mal Bridgeman]

Originally Posted by Mark Chase

Do what ever works for you, but don't pretend by using avg depth your not adding a level of aggression.

Mark

One man's "Adding aggression" is another man's "Reducing unneccessary conservatism".

You have been fairly consistent with this view but what I don't understand is why it is so important for you to paint a picture (wrongly I think) that GUE promotes "aggressive deco" ?

Thanks
Mal

[Mark Chase]

Originally Posted by Mal Bridgeman

Mark

One man's "Adding aggression" is another man's "Reducing unneccessary conservatism".

You have been fairly consistent with this view but what I don't understand is why it is so important for you to paint a picture (wrongly I think) that GUE promotes "aggressive deco" ?

Thanks
Mal

From the outside looking in this is the general impression I get.

When i post deco profiles from my dives i regularly get comments from GUE divers asking why i did so much deco? When i look at profiles from some GUE dives I think WOW that must hurt.

I respect any ones choice to do what ever they like but I baulk at comments on a general web site like "more efficient" or "reducing unnecessary conservatism"?

I see it as "minimum necessary" and "sailing close to the wind" and frankly unsuitable for new divers to attempt.

In all areas of diving we round up or down to the safe side. Avg deco doesn't do this, so it bucks accepted diving safety protocols and definitely shouldn't be defended with words like "more efficient". It makes it sound like its better for you than doing more deco.

Unless you planning monster 3+hour deco dives where dehydration, cold and fatigue are serious health issues, there is really no excuse for not doing plenty of deco.

ATB

Mark

[Mal Bridgeman]

Originally Posted by Mark Chase

From the outside looking in this is the general impression I get.

This is important to make clear though. The impression you have and give may not be connected to the reality of the situation. Whenever people "promote" GUE's approach to the subject they always makes it clear that the deco part does not exist on its own, but is part of an integrated system of diving that you need to invest a lot of money and time learning the skills associated with the subject and also learning the intricacies of the approach and where the pinch points are in the approach. I don't believe the image you paint of a reckless approach to reducing time in the water as a goal in itself is either right or fair.

Don't you think that considering the conservative approach to most diving matters that GUE has (especially at these entry levels), that would carry through to its approach to deco?

Originally Posted by Mark Chase

When i post deco profiles from my dives i regularly get comments from GUE divers asking why i did so much deco?

These profiles show you doing a lot more deco than your computer requires of you in the main. Do you view doing the deco your computer requires aggressive?

Originally Posted by Mark Chase

I see it as "minimum necessary" and "sailing close to the wind" and frankly unsuitable for new divers to attempt.

Do new divers attempt this, though?

Originally Posted by Mark Chase

In all areas of diving we round up or down to the safe side. Avg deco doesn't do this, so it bucks accepted diving safety protocols and definitely shouldn't be defended with words like "more efficient". It makes it sound like its better for you than doing more deco.

Rather than thinking of competitive words like better, agressive, efficient could you consider it as just a different approach? It's not the first subject over which GUE has taken a different approach from the mainstream .... if people want to dive this way, they should go on the course to learn it properly then make their own assessment on its suitability for them ..... not launch brick bats from the sidelines, I think.

Originally Posted by Mark Chase

Unless you planning monster 3+hour deco dives where dehydration, cold and fatigue are serious health issues, there is really no excuse for not doing plenty of deco.

The research is being informed by monster 10hour bottom times @90m with run times over 26hours where addressing nutrition, hydration and warmth, coupled with the limits of human endurance etc are beyond the extremes that I can conceive. I have no view other than to marvel at the astonishing things they are doing. If there are things they are learning which challenge accepted beliefs from research conducted by beardy weirdos in laboratories years ago, then I'd really like to find out about it.....with out being painted as being a reckless or agressive diver.

Cardiovascular fitness and non smoking plays a part as you know, but is rarely brought into the equation.

Mal

[Gareth Burrows]

Originally Posted by Mark Chase

I see it as "minimum necessary" and "sailing close to the wind" and frankly unsuitable for new divers to attempt.

In all areas of diving we round up or down to the safe side. Avg deco doesn't do this, so it bucks accepted diving safety protocols and definitely shouldn't be defended with words like "more efficient". It makes it sound like its better for you than doing more deco.

• We round the depth down to the nearest 3 metres to add conservatism
• We round the time up to the nearest 5 or even 10 minutes to add conservatism
• We round the deep stop depths down to add conservatism
• We add time to the shallow ascent to add conservatism
• We pad the deco and the most conservative viewpoint wins

there are plenty of factors in ratio deco that add conservatism into the mix, but we can always adjust it more due to workload, hydration, day of the week, colour of the moon, any other factor we are interested in.

Sometimes I think the problem is that people see ratio deco as a "how to". This is how you do your deco. You do A then B then C. Ratio deco isnt like this. You learn what works, and what really works, and you change the deco accordingly on the day. then you add whatever safety/conservatism factors you agree are appropriate. We might add more if the water has been colder than expected, or the workload harder, the viz worse, or if someone just decides today is the day to do 10 more minutes. And the most conservatist viewpoint wins in the water. This lack of a defined ruleset is what confuses many people about ratio deco and makes them think it's aggressive.

Anyway, keep it coming chasey, I always enjoy these little discussions


G

[Mark Chase]

Originally Posted by Mal Bridgeman

This is important to make clear though. The impression you have and give may not be connected to the reality of the situation. Whenever people "promote" GUE's approach to the subject they always makes it clear that the deco part does not exist on its own, but is part of an integrated system of diving that you need to invest a lot of money and time learning the skills associated with the subject and also learning the intricacies of the approach and where the pinch points are in the approach. I don't believe the image you paint of a reckless approach to reducing time in the water as a goal in itself is either right or fair.

Reckless is not the word I would choose nor is it a word that fits into any aspect of GUE training. Aggressive is merely a statement of fact. A descriptive term and not meant to be derogatory.

I know many non GUE divers who use aggressive deco successfully.

If i set my computer to 80/100 it would be aggressive? If it set it to 10/125 it would be aggressive. It just is.

More emphasis on cautious building up a personal picture of how a person reacts to deco and more emphasis on the profiles adopted and gases used by GUE would help remove my concerns. Unfortunately this is sometimes forgotten in posts.

There has to be a level of acceptance that doing less deco, no mater what profile or gas used, reduces the margin for error.

When i point this out some GUE divers take it as almost a personal insult. Its not meant to be its just a caveat.

Don't you think that considering the conservative approach to most diving matters that GUE has (especially at these entry levels), that would carry through to its approach to deco?

The emphasis would appear to be on calculating decompression based on efficiency rather than on healthy safety margins. Padding out and erring on the side of caution doesn't seem to be emphasized.

These profiles show you doing a lot more deco than your computer requires of you in the main. Do you view doing the deco your computer requires aggressive?

I set my computer on an aggressive (for me) setting of 10/90 and then I pad the shallow stops. I want the computer to tell me my minimum time and then i use my brain to add a safety margin.

My computer suggests the deep stops (The 10 bit) but i can ignore them in an emergency and I'd run a much more aggressive profile still calculated on a 90GF for the shallow stops.

If I needed out ASAP due to being ill or injured. I would blow off or cut short the deep stops then let it recalculate the 90GF from 12m and up. This is apposed to the GUE or VPM method but on paper its the fastest rout out.

Do new divers attempt this, though?

When i read up on GUE's views on helium reducing deco rather than increasing it, i experimented with reducing the He content id program into my old computer (VR3).

It worked. I didn't get bent. Id tell the VR3 I was diving 14/45 when in fact i was diving 14/65trimix. Sure enough it reduced my deco and i didn't get bent.

Then I decided i was being unnecessarily aggressive and went back to telling it the truth.

Never underestimate the power of the Internet to influence peoples ideas.

Rather than thinking of competitive words like better, aggressive, efficient could you consider it as just a different approach? It's not the first subject over which GUE has taken a different approach from the mainstream .... if people want to dive this way, they should go on the course to learn it properly then make their own assessment on its suitability for them ..... not launch brick bats from the sidelines, I think.
The research is being informed by monster 10hour bottom times @90m with run times over 26hours where addressing nutrition, hydration and warmth, coupled with the limits of human endurance etc are beyond the extremes that I can conceive. I have no view other than to marvel at the astonishing things they are doing. If there are things they are learning which challenge accepted beliefs from research conducted by beardy weirdos in laboratories years ago, then I'd really like to find out about it.....with out being painted as being a reckless or aggressive diver.

I agree totally. I can well understand the need to find the limits of deco theory when your pushing big dives. I do.

I have looked at every trick in the book to reduce my deco on dives estimated at a mere 5-6 hours. Running my "normal" profile on a dive to 130m dive I got a run time of six and a half hours.

In doing so i am pushing personal endurance and pushing my scrubber. So in this instance I have planned much more aggressive decompression taking advantage of modern thinking. I have used gas selection and VPMB's approach to the use of helium to reduce the time comfortably below five hours.

This will improve my safety on physical issues and scrubber issues and so its a risk I am prepared to take in order to get the dive done.

Its not a risk I can justify on tomorrows 45m dive on the Moldavia.

As a result I see no need for average depth calculations on exposures of less than three to four hours in water time.

Cardiovascular fitness and non smoking plays a part as you know, but is rarely brought into the equation.

Mal

[/quote]


Very true and GUEs emphasis on not smoking and general fitness is to be applauded.

When ever i put up a profile or a suggestion that could be in any way perceived as a benchmark (for want of desperately searching my feeble mind for a better word) you will no doubt have noticed I put:

"44years old, moderate fitness, light smoker, two+ stone overweight"

at the end.

This is important information. So is:

"25, non smoker, fit as a fiddle, regular cardiovascular exercise regime".



ATB


Mark

[liamm]

I should add that the average depth request was more with mulit level dives in mind rather than cutting deco. I'm new to "deco" diving so for the next few months i dont see myself racking up alot of deco.

In terms of adding time to deco or padding it am i right in thinking that as long as you are at less that 80% of the atas then adding time will not incurr a deco penalty?

Reason i ask is that the min deco tables that mal linked to make alot of sense, but they do suggest that you should add deep stops

"Since the table's first stop is at 40ft/12m all you have to do is add 1-2 minutes at 50ft/15m - if you dive to 100ft/30m that is."

[neilh]

Originally Posted by liamm

Reason i ask is that the min deco tables that mal linked to make alot of sense, but they do suggest that you should add deep stops

Keep in mind that the min deco tables Mal linked to are designed for a GUE/DIR approach and therefore as Mal said lots of other considerations come into play - such as the gas you're using, the ascent profile, etc, etc.

[Mal Bridgeman]

Originally Posted by liamm

In terms of adding time to deco or padding it am i right in thinking that as long as you are at less that 80% of the atas then adding time will not incurr a deco penalty?

Simply put ... no.

Remember the basic OW training which says that bottom time finishes when you makes a direct ascent to the surface. If you don't make the direct ascent (or in the case of a deco diver, an ascent to the prescribed schedule) then you are in fact extending the bottom time, albeit at a shallower depth and almost certainly reducing the average depth by an amount.

So whilst your fast tissues will be off gassing, your slow tissues could well still be on gassing.

HTH
Mal