PADI Deep Diver course- gas management

[wetb4igetinthewater]

Actually, there is very little PADI bashing, considering the number of dive centers and instructors and global reach. On SB, it is mostly the same few people, over and over.

Well some of you sure complain about it a lot.

I've met a large number of quite good PADI instructors, and very few that are not very good. But I don't know your area, and I'm not really familiar with most of Asia except for the better diver centers.Asia seems to be a problem; witness the expulsion stats in the Undersea Journal.

I have yet to meet a PADI instructor working for a shop that isn't under pressure to get the class over with. So yeah, the instructor going above and beyond is a rarity. I've lamented with other SDI instructors that few add appropriate skills/dives to add value over minimum standards. And that's an agency where it is allowed.

So yeah, hardly ever are instructors adding information. If you were to ask them about gas density or GF, they'd look at your like a deer caught in the headlights. Feel free to respond, I've said more than enough.

 

[crofrog]

The RDP, your computer, nothing specific.

That’s interesting if I’m understanding you. You could have a class being conducted at 100/100?

If you're asking if He is required beyond 100 ft, no. Nor in TDI, et al. Just GUE, as far as I know.

I’m not aware of any either, and it seems very head in the sand to pretend like that research that didn’t exist when the classes where originally created don’t exist.

 

[tursiops]

You could have a class being conducted at 100/100?

Very unlikely. Anyone who could set their computer to that likely knows better than to do it.
The worst that is likely is GFHi of 95 ("Low" Conservatism), so similar to the RDP.

 

[boulderjohn]

OL, and why is there so much PADI bashing?

Because you post so much.

 

[wetb4igetinthewater]

Because you post so much.

Touche!

 

[crofrog]

Very unlikely. Anyone who could set their computer to that likely knows better than to do it.
the worst that is likely is GFHi of 95 ("Low" Conservatism), so similar to the RDP.

Sure, so is teaching a drysuit class to someone who can't hook up their drysuit inflator.

I just find it interesting there is no required conservatism.

There is a potential that someone could be diving 100/100 or even 95/95 and then have a 60ft/min ascent with a computer that is expecting a 30ft/min ascent and be surfacing exceeding 100% gf, which sure isn't guaranteed bends, but defining a maximum GF or max bottom time at that depth would help define the risks for the agency.

 

[tursiops]

Sure, so is teaching a drysuit class to someone who can't hook up their drysuit inflator.

I just find it interesting there is no required conservatism.

There is a potential that someone could be diving 100/100 or even 95/95 and then have a 60ft/min ascent with a computer that is expecting a 30ft/min ascent and be surfacing exceeding 100% gf, which sure isn't guaranteed bends, but defining a maximum GF or max bottom time at that depth would help define the risks for the agency.

No, the 60 ft/min is a maximum rate not to exceed. If you are diving a computer, you are limited to the ascent rate for that computer.

Added: that is one of the overall PADI Training Standards for ALL classes.

Maximum ascent rate is 18 metres/60 feet per minute, or the maximum rate allowed by the diver’s computer, whichever is slower.​

 

[Josh the diver]

Sure, so is teaching a drysuit class to someone who can't hook up their drysuit inflator.

I just find it interesting there is no required conservatism.

There is a potential that someone could be diving 100/100 or even 95/95 and then have a 60ft/min ascent with a computer that is expecting a 30ft/min ascent and be surfacing exceeding 100% gf, which sure isn't guaranteed bends, but defining a maximum GF or max bottom time at that depth would help define the risks for the agency.

not every one is diving a shearwater with customizable GF. there are a lot of computers that run different algorithms that don't use GF.

a lot of computers just have some form of a conservatism setting of low, medium, or high. which are all generally safe with just assuming more risk.

 

[crofrog]

not every one is diving a shearwater with customizable GF. there are a lot of computers that run different algorithms that don't use GF.

a lot of computers just have some form of a conservatism setting of low, medium, or high. which are all generally safe with just assuming more risk.

Sure that doesn't matter. Without some sort of maximum exposure defined for the class you're allowing individual instructors to define what the maximum risk is for the class. PADI defined half of it. Max Depth 130ft (40m), but not the other pieces which are time at depth, and minimum decompression time.

Those instructors could pick what the majority of the community would consider reasonable defaults like 40/85 (the default for medium on shearwater and Garmin) or something more conservative like the high conservatism settings. Generally speaking for new divers engaging in their first deep dives, a more conservative approach is probably warranted but it is instead left entire up to the instructors, and doesn't appear to be something that is covered in the academics for the class.

There are a lot of disagreements about what efficient decompression looks like, but there is I think little to no debate that that increased time under increased pressure increases the risk of DCS, and that DSC is the number 2 most common injury scuba diving.

 

[boulderjohn]

PADI defined half of it. Max Depth 140ft (40m), but not the other pieces which are time at depth, and minimum decompression time.

I am becoming thoroughly baffled. We are still talking about a NDL class, aren't we? If so, what does minimum decompression time have to do with things? PADI does define the maximum depths for those dives, but you don't have to reach those maximum depths, and since time at depth depends upon the depth, then of course is it sup to the instructor teaching the specific dive.

As for gradient factors and the like, the computer program starts with an algorithm that was determined through research to be acceptably safe, meaning it can be used as it. Yes, many people do use some means of making it even safer, but that is a personal preference, and that personal preference would make for an excellent discussion for dive planning.