which dive tables?

Please register or login

Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

Benefits of registering include

  • Ability to post and comment on topics and discussions.
  • A Free photo gallery to share your dive photos with the world.
  • You can make this box go away

Joining is quick and easy. Log in or Register now!

maged_mmh

Contributor
Scuba Instructor
Messages
3,421
Reaction score
7
Location
Egypt
# of dives
100 - 199
Hi all,
Although I depend most of the time on PADI RDP, I was wondering if it is the most used one, or how many out there else?
I have access to BSAC one as well.
but what about the other versions? are they more conservative/valid?
of course one can always depend on a computer, but I like to consult tables as well.
thanks.
 
PADI's RDP is the most widely used set simply because PADI is so big. It is the most liberal table I've seen. I don't trust it, especially on repetitive dives. Most agencies have their own tables, most of them are based on the US Navy tables. Of those, YMCA's is generally the most conservative, although others are more conservative at various depths. The DCIEM tables are not based on the Navy tables and use a totally different format, but they are overall the most conservative table I've seen.
 
I'd recommend getting your hands on a bunch of tables and comparing them to see which you are most comfortable with.

For no-stop diving, I do use DSAT (PADI) tables quit a bit, only because I taught them for so long and pretty much have them memorized. However, I don't dive tables to their limits.

I've used the IANTD Buhlman tables quit a bit especially on staged decompression dives. Again, because I was an IANTD instructor.

I also have US Navy, NOAA and who knows what other tables laying around.

I think NAUI has some RGBM tables now and I think the new IANTD tables are one of the bubble models...VPM maybe?

Another thing you might want to look at is decompression software. You can compare lots of different models from RGBM, VPM and modified Haldanian models like Buhlman using gradient factors.

I know the bubble models are all the rage these days but I'm still pretty comfortable with the Buhlman with gradient factors. Even if you're doing no-stop dives, the gradient factors let you adjust the conservatism with the reference point being the 'M' value of the leading compartment.

Carry a palm pilot with some software on it and you can have you own tables configured just the way you like them right down to specifying ascent/descent rates, breathing gas and conservatism.

Having a good look at some of the above, might also help you decide if your dive computer is spitting out profiles that you actually want to dive....that is, if you even continue to bother with the dive computer.
 
but where can one get these tables?
I got what I have when I got certified with PADI and BSAC
 
Depends what diving you want to do.

BSAC 88s are decompression tables - the padi RDP isnt.

So if you want to choose between those 2 and want decompression you only have one choice - the 88s.

However i dont dive with the 88s and most people dont. They're aggressive to the point of being frightening for some profiles, especially when you start repeating. Unlike other tables that have been updated with doppler data and so on the 88s havent. The model behind the tables are also kept secret and never published so its not open to peer review,scrutiny or for anyone to make an objective assessment on their safety. Im not a fan of trusting myself to 18 year old secret dive tables on deep/deco dives.
Another thing to remember is if using nitrox you cant use EAD on the BSAC tables. (The person that made them said it wont work but as the methodology isnt published nobody can see why not).

You may want to look at SAA tables which are basic buhlmanns - these'll allow your no stop and deco in the way bsac do.

If you're aiming for proper planned deco diving id suggest cutting your own using VPM or maybe buhlmann gradient factors off a computer.
 
Where to get them...

Several (most?) agencies sell tables so you can get them from a dive shop and no doubt some of the online retailers too. The Navy and NOAA tables can be found in their respective manuals as well as other publications...I'm not sure about waterproof cersions.

Diverite and GUE market decompression software. VPM software can be had in Vplanner and others. The same for RGBM. I don't have URL's handy but a google search should turn them up. There is a good deal of free decompression software available online too...including source code should you want to write your own.
 
Hello maged mmh:

All tables are conservative in that they will protect all but the most sensitive diver on his worst day. The PADI RDP was tested in both a hyperbaric chamber, in the open water, and in a multiday trial. All of these were done using a Doppler bubble detector. The methods and results were presented at scientific meetings and the references are below. I was the individual (MRP) in charge of the test program.

One always has the option of adding time to a table format and producing something that is more conservative.:wink:

Dr Deco :doctor:



References

MR Powell and R Rogers. Gas phase formation as detected by Doppler ultrasound in
divers performing multilevel and repetitive dives. The Physiologist, 30 (4), 134, (1987).

MR Powell, MP Spencer, and RE Rogers. Doppler ultrasound monitoring of gas phase formation
in divers performing multilevel and repetitive dives. Undersea Biomed. Res. 15, Suppl., 84-85 (1988).

R Rogers and MR Powell. Development of multilevel and repetitive tables for
recreational divers. Undersea Biomed. Res., 15, Suppl., 84 (1988).

MR Powell, and RE Rogers. Doppler ultrasound monitoring of gas phase formation and
resolution in repetitive diving. Undersea Biomed. Res., 16, Suppl., 69, (1989).

Hamilton, RW, RE Rodgers, MR Powell, and RD Vann. Development And Validation Of
No-stop Decompression Procedures For Recreational Diving. Diving Science and
Technology. (Pp. 78 + appendix). February 28, (1994)
 
All tables are conservative in that they will protect all but the most sensitive diver on his worst day.

This might be a bit of a stretch given the numbers of "undeserved" hits out there.

Personally the bottom times on most of the tables aren't THAT divergent, its the recommended ascent rates which scare me.
 
The real area where all tables currently fail are on repeat day repeat dives.

Most of the "undeserved hits" are by people on multi-day dive trips and so on.
Yes they're technically within the tables but the tables are really stretched.
 
https://www.shearwater.com/products/teric/

Back
Top Bottom