'Safest' air tables

[Woz]

Have just had a copy of the BSAC 88 tables through and comparing them with a Buhlmann set, the deco required for similar dive times seems a whole load less on 88 tables.
Now I have heard from various sources that the 88 tables can be a little shy on deco, and the Buhlmann tables are a bit better, with the USN tables being more conservative than both.
Now these are all opinions from various 'in the pub' sources so I would quite like a reasoned opinion on the above and maybe any other tables people would like to voice an opinion on.

Ta.

Cap'n PugWoz

[chrisch]

The BSAC tables always get a bashing. They are designed for a one big dive and then a little second one, maybe, sort of. That is - they shy from repetitive diving whereas the Buhlmann and its derivatives are designed to give greater off gassing (per dive) to facilitate repetitive diving.

You can't compare the two.

As best I know the BSAC tables do not have a bad record. However the club I dived with were almost all computer (hence AAB's ZHL) users, so there could maybe be some argument about just how much they (88s) have been dived (in last few years).

My only gripe with the 88s is the ascent rate. I think with the better knowledge we have today this should be modified. I suspect Hennesy would agree.

Chris

PS the safest are the Mexican Cavalry tables - well known fact. Stay down til you're bored then come back.

[Woz]

Rats. Sorry if I have dug up a well thumbed old subject. I did scan down the threads first but didn't spot anything...

[chrisch]

No - its a valid point in many ways. The various tables are 'cut' in different ways to give the authors' view on what does and doesn't work.

The BSAC 88s are a bit of an anomaly in that they are not based on the Buhlmann theory. Billy beardie beesack can get a bit hot under the beard when talking about them as the big cheeses parade them (88s) as "safest". I don't know about that!!!

In the final analysis the "safest" tables are (supposedly) the ones that are most "conservative". Whatever that means? I think you will find in practice nearly all the "recreational" tables (inc. 88s) are well tested and the real heated debate starts with the techies doing deep stuff with mix and the like. Most of us dive on a 'puter - which means a Buhlmann ZHL 8/12/16 algorithm with M values set by the manufacturer (according to their fear of being sued).

You will find heated debate on the BSAC forum re. the 88s if you like to read that sort of thing!

Chris

[MATTBIN]

I read the Canadian ones are highly regarded, alas not well known, used or understood.

Of course we all know the Padi ones are USN witha bit of padding, BUT who actually uses tables on repetitive dives anyway?

Matt

[PeteM]

Originally Posted by Woz

Have just had a copy of the BSAC 88 tables through and comparing them with a Buhlmann set, the deco required for similar dive times seems a whole load less on 88 tables.

You need to make sure you are comparing like with like, dive time for the 88's is from head down to getting to the first stop but I think Buhlmann is from head down to leaving the bottom.

[Woz]

Well I dive a poooter anyhow (with another poooter as a backup) but am interested in a general fluffy sort of way, the same way that i am interested in rebreathers but would not fancy diving with one right now.

[Fathoms Down]

Originally Posted by MATTBIN

Of course we all know the Padi ones are USN witha bit of padding

Erm, the PADI RDP is nothing like the USN tables as they are based on different diving styles. The reason PADI produced the RDP is that the USN tables didn't take into consideration repetative dives, multi level diving or people who were less fit that USN divers using them.

[chrisch]

Originally Posted by MATTBIN

Of course we all know the Padi ones are USN witha bit of padding, BUT who actually uses tables on repetitive dives anyway?

Matt

PADI (DSAT actually) reworked the RDP in 1987, just prior to the new BSAC88 as it happens but probably a coincidence, and doppler tested divers to come up with their own M Values independent of any USN influence.

The USN tables are the same format and use 5 tissue types and the same leading tissue group theory and were used (by PADI) in a modified format prior to the 1987 DSAT work.

As such PADI could claim the "safest" as they are doppler tested.

IMHO the tables are used by the agencies to differenciate themselves from one another. All teach mask clearing and swimming ascent etc. as these are the core skills of diving. Having a proprietary dive table is a "selling point". Why else does PADI bother with "the wheel"?

Maybe this too is why BSAC still has such affection for the 88s? I think they are a PITA if you wish to climb the instructional ladder, knowing as you do that within a week or so the newly qualified Ocean Diver will be buying a 'puter and that s/he from that point will be on ZHL16. BSAC is non-commercial it could surely be more liberal in its views of the many tables?

And, Matt, to answer the question - just about no-one until you get to techie level and Woz asked about AIR tables (Air WTF is that?). I agree its a non starter.

Chris

[Woz]

Originally Posted by chrisch

(Air WTF is that?). I agree its a non starter.

It's that clear stuff you are sucking in and blowing out right now. Tell you what, stick your head in a vacuum for 10 mins and see what happens then...