NDL Limit

[MISFIT DIVER]

Not testy, just caught off gaurd by getting flamed. Stupid question or not, it was one I was looking to get answered. Not a big deal.

I do not belive that is the case Walter. I belive my instructor to be compatent. There are only three instructors that work out of our shop. My LDS is not primarily a dive shop. There are not many very experianced divers to learn from or gain experiance from. Some times I think I can learn more out here than from them.

 

[MikeS]

MISFIT DIVER once bubbled...
Would the no-dompression time change if you were using a 100 or 120 cu ft tank?

No, you answered your own question as the gas supply does not effect nitrogen uptake and hence the NDL time.

MISFIT DIVER once bubbled...
If that is true, what would be the reason to use a bigger tank if you are still going to stay with in the recreational limits

Many factors limit your dive time. The two most significant are air supply and nitrogen loading. There are others less significant such as core temperature. The dive should end when any of these factors reach what you have decided is the limit of expectable risk.

For no decompression dives, this is typically the NDL or the minimum gas supply required to get you and your buddy safely to the exit point, whichever comes first. The gas supply and NDL are not directly related.

If based on you diving profiles and air consumption you end your dives based on air supply with remaining NDL time, you could extend your dive times by increasing your air supply.

If you are ending your dives based on NDL than increasing the gas supply will not effect the dive time.

Larger tanks = greater gas supply; increasing the probability of reaching the NDL before you reaching the amount of gas required to get you and your buddy safely to the exit point. But, a word of caution! It also increases the possibility of exceeding the NDL and not realizing it if you are only monitoring gas supply.

Mike

 

[Dryglove]

MISFIT DIVER once bubbled...
There are only three instructors that work out of our shop. My LDS is not primarily a dive shop. There are not many very experianced divers to learn from or gain experiance from. Some times I think I can learn more out here than from them.

Thats cool and all as im sure we are all for learning but you hold a PADI DM certification. How could instructors with little experience be teaching others and certifying dive masters. Every one of us have learned something valuable from this board. I have learned a ton. I guess i just dont understans PADI's way of doing things.

 

[Walter]

Why do to believe your instructor is competent?

 

[MISFIT DIVER]

Well Lal, I do not have an answer. PADI is the only agency that I have delt with and have nothing to compare it to. We all know the debates about agencies and I am far from being one to say one is better then others. I have heard that PADI"s standards may not be as rigid or as demanding as others, I do not know. With my limited experiance I think that some of there practices leave alot to be desired. Some of these have been beat to death and not much need going into them(use the search if needed )

There is alot to learn, some times you have to go elsewere to learn it. Zillions of people out there with lots of info.

 

[Dryglove]

Well you are definitely in the right place as this board is a wealth of knowledge and is definitely the best board on the net

 

[MISFIT DIVER]

Again Walter, based on what I have to compare him too. He seems to follow PADI standars. He is very saftey minded. He is not one of those guys that you say,"Man, that guy knows his sh*t) I know that he is not all about certs, he has failed students for not being able to complete standards. I do not think he is one of those guys that just signs people of for the sake of doing it. I'm sure that there are guys out there that would just blow him away. I would like to hook up with a mentor like that. As of yet, I have not found them.

 

[MISFIT DIVER]

Your right LaL, there is so much info out here. I will just learn to ask the right questions, or the wrong questions the right way

 

[Longhorn]

Before you flame me, I agree the primary factors controlling nitrogen loading are pressure and time. That said, let me propose a situation. You have two divers that are exactly the same in every way and they are diving the exact same profile. Diver one is nice and calm and taking nice slow steady breaths from his regulator. Diver two in sucking on his reg. like a smoker on a cig in an airport parking lot after a 7 hour flight. All that work sucking in air has made diver 2’s heart rate faster than diver 1.

Diver 1 takes a breath of air and some of the nitrogen enters his blood stream leaving the residual air in his lung slightly depleted in nitrogen. Therefore, before he takes another breath, his lungs carry gas that has less than atmospheric values for N content, and the blood that comes into contact with that gas will dissolve slightly less N.

Diver 2 is constantly replenishing the air in his lungs, the N content never drops significantly below atmospheric values, even though roughly the same amount of N is dissolving in his blood stream. Also, his increased heart rate is delivering blood to the lungs that is undersaturated with respect to N thereby increasing (slightly) the flux of N into the bloodstream.

Even though the primary factor controlling the N loading is P and T, diver 2 may still load slightly more N. How much is probably impossible to determine, and probably isn’t enough to effect anything significantly.

I have to cruze home. I’m looking forward to coming to work tomorrow to read all the insightful, well mannered responses. Thanks

 

[Diversauras]

The question was do the NDLs change if you use a different size tank.

I don't mean to flame anyone and I hope the question has been answered but it is like asking if your parachute will work the same if you wear brown boots instead of black ones.