PADI Dive Master Course

[exnewwavedivers]

Se7en:

SAC measured in Bar (as I mentioned before)

Like I said, you would normally calculate air consumption based on liters. It is more flexible, considering we may be using different sizes of tanks, using pressure to calculate would not be accurate.

In the divemaster manual, PADI elected to use bars to illustrate that consumption changes at depth.

Why 60 minute washout is considered safer than expedential

Please rephrase...

Why you should trim a diver so their feet are heavy

You add ankle weights if the feet of a diver is too buoyant.

Why a tank valve needs to be turned off a full half turn

The simpliest and/or most popular explanation is that it makes it easier to check that the tank valve is open. It has its advantage like for example:

Diver turns on tank valve all the way. Another diver checks and the natural instint for most divers is to turn the valve counter clockwise, noticing that it does not move, diver forces it a little bit, that can shorten the life of the valve... oh well, some parts inside.

Please note though that technical divers do not follow this. The idea is to make sure that the valve is open all the way, guranteeing that there will be no restriction on air flow especially when tank is low on air. No worries on other divers checking because other divers are not suppose to touch the equipment of technical divers.

If I can spend 10 minutes at 38 metres

You can't.

Snorkles???

Use skill to learn, gives the diver option of using snorkel when doing surface swim. Most divers though, after gaining experience, do not use snorkels. Some like it though.

Why is a PADI DM or Instructor qualified to dive Solo?

Always with other divers around... students or certified divers.

Why do you have to use the wheel for calculating multilevel dives when the Tables do it just as easily?

To sell the wheel.

 

[Paul168341]

To sell the wheel

As true as this may be, you really shouldn't be calculating multi-level dives on the table form of the RDP. As much of a pain as the wheel is, it really is an amazing tool, and much more precise than the tables; when used correctly. Still not as versitile as a computer though.

BTW, the inventor of the wheel came up with the idea based on a dream he had of it. My CDs knew him personally, from what I hear he's quite a genius. :doctor:

 

[neil]

Originally posted by SubMariner
Neil:
No where did I say that the DM was TEACHING the student.
In the PADI system DMs and AIs (aka Certified Assistants) are dive professionals. When it comes to working with students it IS their responsibility to assist the Instructor in handling students. That includes what I described.
~SubMariner~

Sub,
Understood. I still think the instructor is still more qualified to deal with problem students than a DM. I guess that's my personal belief. If a student is having a problem with a skill, they haven't learned it yet. The teaching is up to me, not an assistant. They pay for MY expertise and experience and that's what they get.
Your comment on the individual vs. PADI standards is what I was getting at in my previous post. So many instructors don't know the standards, or choose to ingnore them. If Mike's instructor had followed the PADI line, HE should have suggested he own a copy of the manual.

Neil

 

[Se7en]

Originally posted by Paul168341

As true as this may be, you really shouldn't be calculating multi-level dives on the table form of the RDP. As much of a pain as the wheel is, it really is an amazing tool, and much more precise than the tables; when used correctly.

Paul - not trying to have a go at you personally, but this is exactly the sort of thing that I don't like. I put the tables vs wheel question forward as one I'd like the explanation for, and you come back with the assertion that "you really shouldn't... the wheel is amazing and more precise"

WHY???

They are both models of the same data, and have the same number of pressure groups. The only difference is that the table has greater intervals between depths than the wheel for deeper dives. The wheel also introduces an arbitrary conservation factor for multilevel dives. (Lets also just ignore the fact that dcompression theory is not this precise anyway).

It may be true that the wheel is a whole lot better, but no one has ever explained why to me... hence I'll stick with the common belief that the wheel is preferred to sell more wheels.

(BTW, from a design perspective I think the wheel is cool, it just doesn't provide any more functionality)

Oh - none of this is a great concern for me personally, as I plan my dives off the tables used by my Alladin Pro, and then dive as per the computer.

ciao
Mike

 

[Se7en]

Originally posted by newwavedivers


In the divemaster manual, PADI elected to use bars to illustrate that consumption changes at depth.

But why do this when it makes more sense in litres? I understand the point that is being made, just don't understand why anyone would choose to make the point using terminaology that is not appropriate for what is being considered.

You add ankle weights if the feet of a diver is too buoyant.

And too boyant is defined as 'can't do fin pivots'?


Succinct explanation of the turning on a tank valve - thanks

You can't.

Hey - you MUST be a PADI instructor. I ask a question, you reply with an assertion, no support for your position at all, completely missing the intent of the question.
And, on top of all that, you are wrong

I said you can spend 10 minutes at 38m, then blathered about M values. If you check the most excellent, should be used always, wheel, you will see the limit for 38m is actually 11 minutes.

Feel free to provide some intellegence on the rest of the question though - It is one which I'm interested in the party line response to.

Use skill to learn, gives the diver option of using snorkel when doing surface swim. Most divers though, after gaining experience, do not use snorkels. Some like it though.

So why is PADI's stance that snorkles must be worn, if most experienced divers don't do so? Surely the standard should be closer to 'do what is appropriate for your skill and the conditions'?

To sell the wheel.

Ahh - the response of a good and honest instructor

Mike

 

[exnewwavedivers]

Se7en:

But why do this when it makes more sense in litres? I understand the point that is being made, just don't understand why anyone would choose to make the point using terminaology that is not appropriate for what is being considered.

Measuring in terms of bars is more consistent with the way we plan our dives. We normally agree on turning back pressure and low on air pressure in the dive planning stage - either with students or certified divers.

And too boyant is defined as 'can't do fin pivots'?

If the diver cannot perform fin pivot to the satisfaction of the performance requirement, obviously, you have to make adjustments with weight distribution.

Hey - you MUST be a PADI instructor. I ask a question, you reply with an assertion, no support for your position at all, completely missing the intent of the question.

I realized that you are actually referring to the wheel in calculating a dive to a depth of 38m. Sorry about that. Your statement though, is uncalled for.

If you stay at 38m for 10 minutes, let's see, 5-minute compartment would be... <getting this small brain of mine to work is like pushing a big tractor in mud> ... 28.5m

Critical ratios vary in different compartments and the 5-minute compartment can tolerate a higher degree of supersaturation. I am not aware though how much the ratio should be for each compartment. Perhaps it's time to move this discission to the appropriate forum. If I can find it, I'll send you the url where you can download a file on bulhmann algorithym.

So why is PADI's stance that snorkles must be worn, if most experienced divers don't do so? Surely the standard should be closer to 'do what is appropriate for your skill and the conditions'?

It's not just PADI... As for the standards being closer to what is appropriate for various diver skill level, then perhaps it should account for the less skilled people.

Some further questions you may ask around is how come the deployment of survival balloon is not a part of any course? Some instructors teach it in the open water diver course, I do in the advanced open water diver course, most, I assume, don't.

Anyway, seeing that you have problems with some of the philosophies and standards PADI has set, I think you should consider moving to another agency that would be more consistent with your beliefs and philosophy. But I must give you credit for asking questions... good ones too!

 

[Se7en]

Originally posted by newwavedivers


I realized that you are actually referring to the wheel in calculating a dive to a depth of 38m. Sorry about that. Your statement though, is uncalled for.

Sorry if it was offensive - sometimes I forget that the reaction to sarcasm is different in the US to here. No offense meant, I was just trying to emphasise what my issue with the course was, and you did throw me an excellent example

Anyway, debating questions on here wasn't really the point, so I'll leave it alone.

thanks
Mike

 

[ScubaCRNA]

And if you lose all your divers and then get tangled up in something and run out of air... you aren't doing a great job as a DM .

I had to really laugh at this picture. Not only would you not be doing a great job as a DM but I'd have to say you were a moron too.

I have been reading the posts of this thread and, though I only have my basic OW and am working on my AOW, I still think that Se7en should finish his course and then do it right. Regardless of the PADI party line, which I am sure is in all training agencies, the "why" of diving must be a matter of taking charge of what you want to learn. If the DM course doesn't teach you the "why" of something you have to go to the books and find out. As I recall, you are an engineer of some sort. Perhaps that is why you have such a keen interest in the "why" of many subjects. I happen to like learning the "why" also, and if you were my instructor then we could have the kind of discussions you are wanting now. Ergo, finish the course, become a DM (more than that if you desire), and take folks like me under your wing for some downright meaningful learning.

I purchased the NOAA 4th edition Diving Manual to have deeper understanding of diving. My instructor wanted the ISDN so he could order one for himself. He, too, likes the "why" of diving. Hope I haven't rambled too much.

 

[exnewwavedivers]

ScubaCRNA:

I agree with you completely. BTW, how is the NOAA book? Good eh?

Another book I can recommend is IANTD Technical Diver encyclopedia. Don't mind the technical diving part yet but if you are into the decompression theories and other physiological aspects of diving, this would be an interesting and useful reference too.

Another one would be the PADI Encyclopedia of Recreational Diving.