Place of dive tables in modern diving

[boulderjohn]

That depends on the computer too. I know who came up with the Navy tables. I have no idea who set the limits on any given computer.

The ones that run DSAT are based on the work of Spencer, Powell, and others in the research leading to the PADI RDP.
The ones that run Buhlmann are based on the decades long work of Buhlmann.
The ones that run RGBM are using an algorithm developed by Bruce Weinke.

There! Now you know.

 

[Storker]

The ones that run DSAT are based on the work of Spencer, Powell, and others in the research leading to the PADI RDP.
The ones that run Buhlmann are based on the decades long work of Buhlmann.
The ones that run RGBM are using an algorithm developed by Bruce Weinke.

What about Suunto's proprietary RGBM based algorithm?

Me I don't care. According to one of my country's leading hyperbaric physicians (who btw is responsible for developing the tables for professional divers), the output from the RGBM algorithm is indistinguishable from the output from Bühlmann for rec and light deco diver. Which is all that i care about, personally.

 

[KenGordon]

What about Suunto's proprietary RGBM based algorithm?

Me I don't care. According to one of my country's leading hyperbaric physicians (who btw is responsible for developing the tables for professional divers), the output from the RGBM algorithm is indistinguishable from the output from Bühlmann for rec and light deco diver. Which is all that i care about, personally.

Buhlmann and the marketing department.

 

[scubadada]

What about Suunto's proprietary RGBM based algorithm?

Me I don't care. According to one of my country's leading hyperbaric physicians (who btw is responsible for developing the tables for professional divers), the output from the RGBM algorithm is indistinguishable from the output from Bühlmann for rec and light deco diver. Which is all that i care about, personally.

Suunto RGBM is quite conservative after the 1st dive, I'm sure it's safe, just like all the other commercially available decompression algorithms.

Indistinguishable from Buhlmann what? It's nonlinear in it's treatment of dives, starts at a GF hi of maybe 90 or 95 and decreases after that. It would be difficult to match. I have almost 2 years of diving Buhlmann as a backup to DSAT, believe me, it is not easy to match algorithms. Have you tried?

 

[scubadada]

Buhlmann and the marketing department.

Some don't care what algorithm they dive, others do.

 

[tursiops]

the output from the RGBM algorithm is indistinguishable from the output from Bühlmann for rec and light deco diver

Maybe close on dive 1, but wildly divergent after that.

 

[Storker]

Suunto RGBM is quite conservative after the 1st dive

Maybe close on dive 1, but wildly divergent after that.

Since I didn't believe what you're saying, I simulated a two-tank rec dive using four different tools/ three different algorithms:

• Suunto Dive Planner 1.0.0.3 (supposedly using Suunto RGBM)
• Diving Log 6 by Sven Knoch (ZH-L16C and 100/100 GF)
• Dive Planner Pro on Android - basically a digital version of PADI's RDP
• PADI RDP on plastic

The diving I simulated was pretty close to something I might well have dived myself:

1. Square profile, 30m depth, 19 minutes bottom time including descent. 10 m/min ascent to 3m, three minutes safety stop
2. 2:00 hrs surface interval
3. Square profile, 25m depth, 27 minutes bottom time including descent. 10 m/min ascent to 3m, three minutes safety stop

Suunto told me I was just at the NDL on both dives.

Diving Log's Deco Calculator using ZH-L16C told me that I had a 3 minute mandatory deco stop on both dives. On dive 1, I got a ceiling after 17 minutes' run time. On dive 2 I had a ceiling after 27 minutes' run time, so I was just at my NDL.

Dive Planner Pro and the PADI RDP told me that my NDL on my first dive was 20 minutes, and on my second dive it was 21 minutes. Reducing my bottom time to 19 minutes on the first dive didn't give any extra bottom time on my second dive due to the granularity of the RDP.

So to summarize my calculated NDLs:

• Suunto: 19min@30m, 27min@25m
• ZHL-16C 100/100: 17min@30m, 27min@25m
• PADI RDP: 20min@30m, 21min@25m

While PADI's RDP was the most conservative on my second dive, the Suunto algorithm was the most liberal one. The difference between Suunto and ZH-L16C was a couple of minutes' bottom time (nothing, really) on the first dive, with Suunto being the more liberal tool. I think I'll continue to believe that there isn't much difference, and that Suunto's reputation for being overtly conservative is really undeserved.

Disclaimer: I haven't bothered to check what the different tools are saying if I skip the safety stops or have a minimal SI between dives.

 

[tursiops]

Disclaimer: I haven't bothered to check what the different tools are saying if I skip the safety stops or have a minimal SI between dives.

But that is exactly the issue, plus what would happen with a fast ascent, or a yo-yo dive, or using a GF less than 100/100 (which I believe no one does and is in no computers that I know of).

 

[ChristophScuba]

I haven't used dive tables in 20 years, now that I'm taking a course the requires me to use a computer with tables I'm regretting leaving the tables behind. I have to learn them all over again.

 

[oldschoolto]

All these Deco "MODELS" are just that models... They are all within a few minutes of each other and really are just playing games as far as I can tell... Deep stops and shallow stops all playing with the same bubbles in the body.. EVERY person is different and these models are just trying to keep everyone from getting bent...

It's fun to talk about Deco, And hear all the different points of views on it.. Put 5 divers in a room and you'll hear 5 reasons why their Deco is the best plan to use and the others are crazy to be used or trusted...

Jim...