Feedback on recent two-tank and dive limits

[Blackcrusader]

Conclusion, Erik Baker did not have recreational diving in mind when he developed gradient factors.

Maybe not. But then again Nitrox was considered not to be safe for recreational divers it was the Voodoo gas. Neither were dive computers when they first came out. Too complicated for non tech divers lol.

As advances are made things that were considered "technical" in the past are now mainstream in recreational diving. After I did my BSAC diving courses in Brunei in the 80's I would go diving in the Philippines in the 80s & 90's to be told by PADI ops that deco diving was dangerous and was not allowed for recreational diving. Yet Deco diving has always been recreational diving for some agencies.

Dr Simon Mitchel I have no doubt would tell you using DC's with GF is certainly suitable for recreational and technical divers. 15 years ago... seems such a long time ago.

 

[old frogman]

Maybe not. But then again Nitrox was considered not to be safe for recreational divers it was the Voodoo gas. Neither were dive computers when they first came out. Too complicated for non tech divers lol.

As advances are made things that were considered "technical" in the past are now mainstream in recreational diving. After I did my BSAC diving courses in Brunei in the 80's I would go diving in the Philippines in the 80s & 90's to be told by PADI ops that deco diving was dangerous and was not allowed for recreational diving. Yet Deco diving has always been recreational diving for some agencies.

Dr Simon Mitchel I have no doubt would tell you using DC's with GF is certainly suitable for recreational and technical divers. 15 years ago... seems such a long time ago.

My concern is not with experienced divers doing deco diving or technical divers, like yourself. It is with Johnny who has just completed a PADI 4 day course. Maybe has done a further 10 or twenty dives using the PADI RDP table for reference and is now considering buying his first dive computer just for recreational NDL dives. He is still coming to grips with buoyancy, not quite efficient at fin propulsion may have some residual issue with maintaining safety stop depth. At this level of diving capability, his maximum operating depth is 60 ft. His theoretical understanding of the RDP is still evolving. Buying a simple dive computer which uses the DSAT algorithm and which automatically sets a safety stop is going to substantially reduce the stress of transitioning from tables to dive computer. If he goes straight to a dive computer loaded with Buhlman & GF, he now has to understand the combined intricacies of Buhlmann combined with GFs. Sure he can read Erik Baker's paper on GFs however there is a big hole in that document's explanation you can drive a truck through. It explains "what" GFs are but it does not explain "how" to implement them in the real world. The manual suppled with the computer also does not adequately explain how to implement GFs in relation to the new recreational diver.

I have done numerous shore and boat dives over the years with people like Johnny and I see issues. Perhaps manufactures and training agencies are moving too fast with progress.

 

[David Carron]

My concern is not with experienced divers doing deco diving or technical divers, like yourself. It is with Johnny who has just completed a PADI 4 day course. Maybe has done a further 10 or twenty dives using the PADI RDP table for reference and is now considering buying his first dive computer just for recreational NDL dives. He is still coming to grips with buoyancy, not quite efficient at fin propulsion may have some residual issue with maintaining safety stop depth. At this level of diving capability, his maximum operating depth is 60 ft. His theoretical understanding of the RDP is still evolving. Buying a simple dive computer which uses the DSAT algorithm and which automatically sets a safety stop is going to substantially reduce the stress of transitioning from tables to dive computer. If he goes straight to a dive computer loaded with Buhlman & GF, he now has to understand the combined intricacies of Buhlmann combined with GFs. Sure he can read Erik Baker's paper on GFs however there is a big hole in that document's explanation you can drive a truck through. It explains "what" GFs are but it does not explain "how" to implement them in the real world. The manual suppled with the computer also does not adequately explain how to implement GFs in relation to the new recreational diver.

I have done numerous shore and boat dives over the years with people like Johnny and I see issues. Perhaps manufactures and training agencies are moving too fast with progress.

Sounds a lot like your concern is not with the algorithm but with its user interface as presented by specific manufacturers.

 

[JMarc]

No disrespect to you. You are an experienced diver. However, you have confirmed that this dive computer is a convoluted apparatus for "new diver" to use.

AFAIK, The Peregrine doesn't have the tech display of the Perdix (the Perdix can show a rec display similar to the one of the Peregrine) and I see nothing harder for a new diver in the rec display than with another computer, and I do find that the color and bitmap display of the Peregrine provides a clearer interface than the segmented LCD of some other computers I've used. With the later I can understand not knowing what is displayed, with the former not. But that's due to the screen and UI design, and totally not related to the algorithm selection.

I can understand being confused by the difference between optional safety stops and mandatory deco one, but that's a matter of training, not computer.

 

[jborg]

My concern is not with experienced divers doing deco diving or technical divers, like yourself. It is with Johnny who has just completed a PADI 4 day course. Maybe has done a further 10 or twenty dives using the PADI RDP table for reference and is now considering buying his first dive computer just for recreational NDL dives.

Johnny got a computer on his wrist for his confined water pool sessions and everything thereafter, probably one with wireless air integration (because the shop wants him to buy the nice one after the course). They never discussed tables in his open water course. He doesn't know or care what algorithm the computer uses, but he's trained to follow it. He won't see mandatory deco stops on it regardless of the GF, because he'll have followed the NDL time countdown, like he's been trained to.

Frankly, if anyone is training OW divers on tables today, they're committing professional malpractice. (My own opinion, clearly.)

 

[David Carron]

I can understand being confused by the difference between optional safety stops and mandatory deco one, but that's a matter of training, not computer.

It seems to me that if a user is confused by a computer's display, especially with respect to something as important whether or not it's safe to surface directly, then at least some of the problem is in the display.

 

[Blackcrusader]

My concern is not with experienced divers doing deco diving or technical divers, like yourself. It is with Johnny who has just completed a PADI 4 day course. Maybe has done a further 10 or twenty dives using the PADI RDP table for reference and is now considering buying his first dive computer just for recreational NDL dives.

Who nowadays uses PADI RDP tables anymore? How is a DC using RGBM going to be any different than one using GF? They both give you NDL times and safety stops in recreational mode. Try calculating a multilevel dive using Padi RDP tables lol

Dive computers can calculate on the fly tables come nowhere close.

 

[Blackcrusader]

. At this level of diving capability, his maximum operating depth is 60 ft.

Where did you get this information from? Training limits only apply to students. A certified OW is certified to the recreational depth limit of 40m for NDL dives. Those new to divng can take more training but can also just do more diving gradually increasing depth. PADI says one should do more training for deeper diving not must. Not that any agency has any authority over how deep a certified diver can go.

You are clearly confusing training standards from WRSTC with certification limits. Section 5.2 is for "Open-Water Training Parameters". Here's what 5.2.3 actually states:

"5.2.3 All dives prior to open water certification shall be conducted during daylight hours at depths between 15 and 60 feet (5 to 18 metres)."

Perhaps you should read these threads.

https://scubaboard.com/community/th...lt-as-aow-is-to-advanced-diving.650458/page-4

Thread 'Dive Accident Insurance Limitations'

Mar 1, 2025

In a recent thread, a poster related a story about having to correct someone's misinformation about dive accident insurance. That misinformation has been repeated often in ScubaBoard threads. The correction is well buried in a long thread, so I thought I would create a dedicated thread that makes it clear and which can easily be linked in future threads. This one specifically refers to DAN accident insurance, but I think it would be good if other companies had their policies clarified here as well.

The misinformed person had stated that dive accident insurance only covers you if you are...

• boulderjohn
• Replies: 80
• Forum: Basic Scuba

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[JMarc]

It seems to me that if a user is confused by a computer's display, especially with respect to something as important whether or not it's safe to surface directly, then at least some of the problem is in the display.

If you don't know if the computer displays safety or a deco stop, that's a UI issue. Looking at the user manual I gave a screenshot above, I've trouble to find this aspect confusing for the Peregrine display.

If you don't know what are safety and deco stops and how to act when the computer shows one, that's a training issue.

Reading the first message, I think we are in the second case, but the thread has drifted away from that aspect a long time ago.

 

[Blackcrusader]

If you don't know if the computer displays safety or a deco stop, that's a UI issue. Looking at the user manual I gave a screenshot above, I've trouble to find this aspect confusing for the Peregrine display.

If you don't know what are safety and deco stops and how to act when the computer shows one, that's a training issue.

Reading the first message, I think we are in the second case, but the thread has drifted away from that aspect a long time ago.

The OP did not exceed NDL and was given a 5 minute safety stop on his Peregrine. His issue was not paying attention to his surface interval and then not paying attention to his Peregrine and dissmissed its warning. .The OP was already cerified but there is a good case for dive shops to offer training courses on dive computers. I'm sure some divers who have a DC would pay for them.


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Admittedly I was distracted by bad viz and shifting currents, as well as keeping close tabs on my teenage son/buddy, and not as focused on depth and time as usual. I did not clock until later that our SI was only 34-35 minutes. I know the Shearwaters skew conservative and initially dismissed the buzzing computer for that, but have been kicking myself ever since.