Long stops

[Wreckie]

I match the empirical dataset criteria for the usn tables as you stated them exactly, being 24 ex military and running the london marathon next year.

This is however pretty irrelevant as i dont really like them having used them quite a bit for work.

As for training i have more than enough in deco (the whys and hows) for the type of diving i wish to do. Unlike in the US, British diving embraces planned deco at an early stage, hence the reason bsac tables have stop times in them and padi/naui ones dont. In addition to the basic bsac (hey that almost rymes) deco training i've done ERD and commercial diving courses which included surface deco in a chamber

As deep scuba says advising me to get training really doesnt help the matter, my question was about the programs and the differences between them and tables, how they should be set up and how best to get useable information out of them, not how to then use that information.

 

[MikeFerrara]

Wreckie once bubbled...

As deep scuba says advising me to get training really doesnt help the matter, my question was about the programs and the differences between them and tables, how they should be set up and how best to get useable information out of them, not how to then use that information.

I explained some of the differences to you and pointed you to where you could find out more.

As far as how the programs should be set up...it's up to you. When it comes to how you set things like gradient factors or whatever use setable parameters a software has, you set it up for the way YOU want to decompress. In some cases changes in these parameters can have a dramatic effect on the schedule the software generates. There's no right or wrong. If it works you were right. You make these decissions based on the theories you buy into and past experience.

 

[Wreckie]

last post wasnt aimed at you mike, thanks for your help/advise, its been informative, and what i asked for.

It was more for some of the other replies who (as tends to happen with forums like this) jumped to conclusions about levels of training, experience and even the kind of shape im in without taking the time to find out first.

Thanks again for your help and sorry about the crossed wires

 

[MikeFerrara]

Wreckie once bubbled...
last post wasnt aimed at you mike, thanks for your help/advise, its been informative, and what i asked for.

It was more for some of the other replies who (as tends to happen with forums like this) jumped to conclusions about levels of training, experience and even the kind of shape im in without taking the time to find out first.

Thanks again for your help and sorry about the crossed wires

Decompression is interesting stuff and I for one love to talk about it. If we all replied with "Go get training" we might as well shut all the discussion boards down because there wouldn't be anything about diving left to talk about.

Besides there's a lot of decompression theory that you won't get in a class. It's the stuff that you have to research yourself in the interest of staying current.

 

[BigJetDriver]

MikeFerrara once bubbled...


Decompression is interesting stuff and I for one love to talk about it. If we all replied with "Go get training" we might as well shut all the discussion boards down because there wouldn't be anything about diving left to talk about.

Besides there's a lot of decompression theory that you won't get in a class. It's the stuff that you have to research yourself in the interest of staying current.

Amen to all of the above, Mike, especially the latter!

BJD

 

[padiscubapro]

100days-a-year once bubbled...
USN had that at 160' 20 min 20' stop 3min and 10' stop 11min.VPMB at 0 conservation gave me 19 minutes less deco with 80%.The chances that you match the empirical dataset criteria for the USN tables are slim and I feel the tables you quoted are even less conservative.The guys who were used as guinea pigs for the USN were 18-25 and in peak conditioning.Keep playing with the software and please get some deco training if you haven't already.

100 days,
I don't have th Navy tables handy but 51m is about 166fsw so the 170ft tables should be used..

wreckie,
The BSAC tables are notious for their bends rate.. US Navy has a rate higer than most consider acceptable (on certain schedules), BSAC is even higher. The model the use has inconsistencies, some profiles are exteremely safe while others result in hits..

Bubble models like Vplanner are trying to control bubble growth and limit the acceptable size of bubbles, wheres traditional haldaneon models try to maximize the offgassing gradient and deal with the bubbles at the shallow stops (indecently they originally though no bubbles would be present withing the limits) anything with gradient factor is limiting this offgassing gradient.

Using a buhlman based model
Depending on the divers fitness and activty level for a 20min bottom time I would expect 30-40 minutes of Deco using Air only
or 25-30minutes using 50%, about the same deco using oxygen (I'd prefer 50% esecially in this case)

In either case my required first stop would be around 21m to minimize bubble growth. I personally would pause at 40m and 30m, I try to not exceed ascending more than 1 atmosphere without a pause.. By forcing a stop I can closely control my ascent rate..

 

[100days-a-year]

PSP,my bad.4 and 15 minutes.After 12 yrs in the Middle East and Europe I have thrown out all metric ability.Wreckie,congrats on the race.I run around 3 hrs,but I'm 40.My IANTD mix class included training on all the software we used to cut tables including how to configure a software porogram.Sorry if I assumed you were untrained due to your unfamiliarity with software,here in the States it's usually part and parcel in decompression classes to explain how tables are generated.

 

[pescador775]

Have been playing around with v planner and deco planner but i have a feeling they are set to mega safe, im after some more realistic settings.

You have to understand the different approaches in terms of culture. The US is a safety conscious and litigious society. In such an environment, which is also enamored of technology, the end result is automatically considered more wise if all risk factors are eliminated. This is in contrast to prior US practice (and current European practice) where risks are managed or balanced to some percentile of the population. Also, where risk is managed to efficiency and a tiny margin of safety may be waived to achieve this result.

A particular set of Americans like to do their own thing, something that is not necessarily officially sanctioned by a recognized authority. They are in love with their computers and with exploring new avenues, that is so long as they are working in the interests of 'safety' and will pay a price to achieve that objective.

This can be seen in the popularity of 'do it yourself' tables. A paradoxical development is the 'get something for nothing or 'damn the risk' attitude which operates in parallel. This is an outgrowth of frontier culture and can be reflected in the attitude of some 'explorer' divers who over fill their officially rated diving cylinders. Of course, in Europe, these same cylinders are rated for the higher pressure anyway, ....officially.

Don't try to figure it out, just use the BSAC tables.

 

[flw]

You have to understand the different approaches in terms of culture. The US is a safety conscious and litigious society. In such an environment, which is also enamored of technology, the end result is automatically considered more wise if all risk factors are eliminated. This is in contrast to prior US practice (and current European practice) where risks are managed or balanced to some percentile of the population. Also, where risk is managed to efficiency and a tiny margin of safety may be waived to achieve this result.

A particular set of Americans like to do their own thing, something that is not necessarily officially sanctioned by a recognized authority. They are in love with their computers and with exploring new avenues, that is so long as they are working in the interests of 'safety' and will pay a price to achieve that objective.

This can be seen in the popularity of 'do it yourself' tables. A paradoxical development is the 'get something for nothing or 'damn the risk' attitude which operates in parallel. This is an outgrowth of frontier culture and can be reflected in the attitude of some 'explorer' divers who over fill their officially rated diving cylinders. Of course, in Europe, these same cylinders are rated for the higher pressure anyway, ....officially.

Don't try to figure it out, just use the BSAC tables.

With respect, I don't think the culture thing has anything whatsoever to do with it - deco-planner was originally written by a Brit to start with.
The BSAC tables were written 15-16 years ago, when diving was almost in a different 'era' - in clubs, most diving was done with a 15l or `5+3, which tended to limit the amount of deco you could get into in the first place, and although taught, apart from the very early diving, very few used them, but most went straight to computers.
Deco-planner and the like, for their era were the best around, now slowly being overtaken by v-planner/rgbm etc - many of the programmes are written by divers for their own use, and no commercial profit made from them - they can also be as 'safe' or aggresive as you want - however since you are only using theoretical mathematical models of something we don't really understand, how 'safe' or otherwise they are is a bit of a moot point.
rgds

Fi