Insta-buddy DECO Diver: What’s NDL?

[rabe]

I'd say that most of the divers I meet on the boat have a very low understanding (or not all) of what NDL is, what decompression means, and why is important to check those numbers.
I've also seen and heard terrible things like "you don't need to dive with a computer, it's shallow here and you follow the guide", a dive master saying to students "with nitrox you can stay longer because you use less gas", and the most wonderful of everything "My computer is set on 100% oxygen because air is oxygen... isn't it?"...
Who's to blame?
The instructor? The agency? The student?
I think they should share the blame...

 

[Bob DBF]

I'd say that most of the divers I meet on the boat have a very low understanding (or not all) of what NDL is, what decompression means, and why is important to check those numbers.
I've also seen and heard terrible things like "you don't need to dive with a computer, it's shallow here and you follow the guide", a dive master saying to students "with nitrox you can stay longer because you use less gas", and the most wonderful of everything "My computer is set on 100% oxygen because air is oxygen... isn't it?"...
Who's to blame?
The instructor? The agency? The student?
I think they should share the blame...

I'd put the instructor at the top of the list, he is teaching NDL diving, it would be good for students to understand the line between NDL and deco.

Students get a pass, the importance of information to them is what the instructor presents as important. This changes over time as I believe a diver should gain more knowledge of diving as he continues to dive.

I'll bet the agency has the information in their OW manual and directs the instructor to teach it in the class outline.

Some of the blame goes to the dive computer and its replacement of training on tables. With tables it is easier to see the line you cross into deco. PADI actually had some deco stops on the old tables in case a diver went into deco, the new tables give rules to turn the safety stop mandatory and extend the stop time instead of actual calculations. On computers you read about the change in the computer screen. If there are a number of different computers in class I can almost hear the instructor telling students to read the manual because there is not the time to cover every computer. At that point deco seems unimportant as you are just training yourself.

Last but not least there are some knuckleheads that can pass a class and retain nothing. It's not a large group and eventually Darwin sorts them out, however it sucks when you get buddied up with one.


Bob

 

[aquacat8]

Sigh, I am remembering my first class, I was shocked and disappointed to learn that I could not swim down as deep as my little fins would take me for as long as I wanted as long as I had air. Sigh. Would that it were so.

 

[Frosty]

Rabe--Im hoping that what you have heard was someone taking the mickey (poking fun)
I have to admit to have said every single one of those things to customers at some point in time.
The sage nod or confused frown tells me pretty fast A their actual knowledge and B if they are actually listening/ understanding to the dive/boat brief Im giving.--To be clear-they are told the true story right away.

 

[Jay]

Even in my limited experience I've heard the 'what's NDL' question before. This was post briefing. I suspect it won't be the last time

 

[Soloist]

I'd say that most of the divers I meet on the boat have a very low understanding (or not all) of what NDL is, what decompression means, and why is important to check those numbers.
I've also seen and heard terrible things like "you don't need to dive with a computer, it's shallow here and you follow the guide", a dive master saying to students "with nitrox you can stay longer because you use less gas", and the most wonderful of everything "My computer is set on 100% oxygen because air is oxygen... isn't it?"...
Who's to blame?
The instructor? The agency? The student?

The diver is ultimately responsible. A certified OW diver should have a basic understanding of dive theory, dive planning, risking avoidance and proper equipment usage, assembly and function. If in doubt, don’t dive. How many divers are thumbing dives due to ignorance?

Even in my limited experience I've heard the 'what's NDL' question before. This was post briefing. I suspect it won't be the last time
I think they should share the blame...

When we took our OW training nine years ago dive computers and the “NDL” acronym were barely acknowledged, however, safe dive planning using recreational dive tables was strongly emphasized. Plan the dive - dive the plan. Are divers with minimal understanding of dive computers actively checking their handy plastic Recreational Dive Planner tables?

 

[Bob DBF]

How many divers are thumbing dives due to ignorance?

Dives one dosen't make are no problem, the real issue is divers making a dive due to ignorance.

Are divers with minimal understanding of dive computers actively checking their handy plastic Recreational Dive Planner tables?

My understand that tables no longer have to be taught...


The diver is ultimately responsible and will feel the consequences of his actions, but where does that put a new OW diver when trained by a substandard instructor? If one is not trained what NDL and deco are, how are they to stay in one and out of the other. Over time I would expect more, the diver should remediate the poor training.



Bob

 

[Dan G]

The diver is ultimately responsible. A certified OW diver should have a basic understanding of dive theory, dive planning, risking avoidance and proper equipment usage, assembly and function. If in doubt, don’t dive. How many divers are thumbing dives due to ignorance?

When we took our OW training nine years ago dive computers and the “NDL” acronym were barely acknowledged, however, safe dive planning using recreational dive tables was strongly emphasized. Plan the dive - dive the plan. Are divers with minimal understanding of dive computers actively checking their handy plastic Recreational Dive Planner tables?

I agree that the diver is ultimately responsible, but many don't know what they don't know. In fact, they are doing what they have been taught so it is hard for me to place 100% of the blame for their ignorance on them. I have read here on SB that dive tables are no longer used in OW courses in lieu of computers. I can see why, but perhaps we are seeing the impact of this. Perhaps computers lead to a more abstract understanding of NDLs, making them seem 'less real' in a sense. When we need to calculate with tables, perhaps the concept of 'limited amount of time at a certain depth' is more likely to be concrete and bought into.

On a boat last year, we were set to do a dive that was going to be, very briefly, very close to MOD. One guy on the boat asked the DM about reprogramming his computer to 1.6 PPO for the dive. After the dive, I mentioned how my computer 'got mad at me' for being so close to my MOD for those few seconds. The same guy who had his computer reprogrammed scoffed and stated that he "doesn't do those kinds of things." I let it go, but this diver seemed to have no idea that he and I did precisely the same thing. We both allowed our PPO to get close to or slightly exceed 1.4. He programmed his computer so that his alarm did not go off, while I knew what was going on and understood what my actual PPO was when we reach our max depth. His knowledge does not extend beyond what his computer is telling him and he knew that if he gets the DM to change a setting, he is safe because his computer is telling him so.

Sorry for the tangent, but this seems related.

 

[Saboteur]

My son just finished PADI OW training and he was taught tables, but not computers. I found that odd since I thought tables are no longer taught as well.

 

[uncfnp]

I wonder too about new divers that aren’t taught tables then dive with out personal computers. They either rent computers they don’t understand or worse yet dive based on another’s computer.