What happens in a recreational computer if you go past the NDLs?

[boulderjohn]

When I was first learning how to operate it I was having the same problem and then I read the manual http://elearning.padi.com/company0/tools/eRDPML_InsforUse.pdf and watched some youtube videos. It was not very intuitive to me for some reason. I would also contend that if everyone had to learn the tables initially then LDS would sell a lot more computers.

As I have related many times in the past, I learned to dive using tables 20 years ago. On my first dive trip (Cozumel), I tried to use my tables after my first DM-led multi-level dive, and I found I was off the tables by a long shot. I got a computer before my next trip. My attempt to use tables on that dive remains the only time I have ever seen any recreational diver attempt to use tables (or eRDPml, which is the same thing) for dive planning outside of a class.

 

[mi000ke]

Just finished reading this thread after reading the one about the 4 instructors who all ran out of gas on a deep dive, and I am reminded of what one of my university professors told me 50 years ago, "There will always be more horses asses in this world than there are horses."

Diving without knowing how your computer works? Diving without understanding how to create a dive plan? Diving without checking your gas and ndl regularly? Come on, man!

 

[Ghost95]

And some people still scoff at the DAN insurance......

 

[tarponchik]

As I have related many times in the past, I learned to dive using tables 20 years ago. On my first dive trip (Cozumel), I tried to use my tables after my first DM-led multi-level dive, and I found I was off the tables by a long shot. I got a computer before my next trip. My attempt to use tables on that dive remains the only time I have ever seen any recreational diver attempt to use tables (or eRDPml, which is the same thing) for dive planning outside of a class.

I used tables till 2010 (although I occasionally rented a comp).

 

[fuzzybabybunny]

I'd like to get a better idea of how the computer will behave should you go past the NDLs. The computer will give you decompression stops, but how long will they be and at what depths and how many stages?

If you go to 130ft but don't go past your NDL, a slow ascent with a 3 minute safety stop at 15ft is enough.

If you go to 130ft but stay, say, 5 minutes longer than the NDL, what would a decompression profile look like on a recreational computer versus a tech computer?

 

[Lorenzoid]

I'd like to get a better idea of how the computer will behave should you go past the NDLs. The computer will give you decompression stops, but how long will they be and at what depths and how many stages?

If you go to 130ft but don't go past your NDL, a slow ascent with a 5 minute safety stop at 15ft is enough.

If you go to 130ft but stay, say, 5 minutes longer than the NDL, what would a decompression profile look like on a recreational computer versus a tech computer?

There is no reason a technical computer and a recreational computer could not use the same algorithm and therefore give you the exact same ascent profile. I can set my Shearwater Petrel on "Rec" mode or "Tec" mode, but if I exceed NDL displayed in Rec mode it's going to give me the same profile it would have in Tec mode. That said, computers marketed as "rec" generally give you an ascent profile that gets you to the surface as fast as possible. A computer aimed at tec, i.e., deco diving, generally has a feature that allows the diver to control the profile, such as gradient factors. The Shearwaters allow you to set custom gradient factors even in Rec mode, so you could indeed control how your ascent profile would look if you were to exceed NDL.

 

[lv2dive]

All computers are different. You should read the manual to understand how your computer works, or if you bought it at an LDS, ask them to go over it with you.

I'd like to get a better idea of how the computer will behave should you go past the NDLs. The computer will give you decompression stops, but how long will they be and at what depths and how many stages?

If you go to 130ft but don't go past your NDL, a slow ascent with a 5 minute safety stop at 15ft is enough.

If you go to 130ft but stay, say, 5 minutes longer than the NDL, what would a decompression profile look like on a recreational computer versus a tech computer?

 

[rsingler]

Just finished reading this thread after reading the one about the 4 instructors who all ran out of gas on a deep dive, and I am reminded of what one of my university professors told me 50 years ago, "There will always be more horses asses in this world than there are horses."

Diving without knowing how your computer works? Diving without understanding how to create a dive plan? Diving without checking your gas and ndl regularly? Come on, man!

Awww @mi000ke , come on, man!
I think you're a little sensitized by that BBC thread (as am I).
But heck! Look at the OP. That is to say, post #1.
Sure, he could'a found the answer in his manual. But maybe he looked and didn't quite understand the deco computation ability described (in a recreational computer). So he asked his buddies on SB! Oh, oh! Big mistake.

Don't paint him with the BBC brush!
Hey, good for you for asking, @fuzzybabybunny !
(Then, again, this IS Scubaboard...)

 

[fuzzybabybunny]

All computers are different. You should read the manual to understand how your computer works, or if you bought it at an LDS, ask them to go over it with you.

The computer that I have simply says it'll give me a deco profile. That's it. No indication of how long, how many stops, etc. Does a simple 3 min safety stop at 15ft turn into 60 minutes of deco at multiple levels if you go over your NDL by five minutes at 130? It doesn't give any kind of an idea of what to expect.

 

[JohnnyC]

The computer that I have simply says it'll give me a deco profile. That's it. No indication of how long, how many stops, etc. Does a simple 5 min safety stop at 15ft turn into 60 minutes of deco at multiple levels if you go over your NDL by five minutes at 130? It doesn't give any kind of an idea of what to expect.

It won't tell you how long and how many stops are required as that is a function of your depth and time and by how much you've exceeded your NDL.

As for how much deco you will have for blowing your NDL by 5 minutes at 130fsw, that's dependent on the algorithm that your computer uses.

Your manual should be telling you what type of information the computer will display, where it's located, and what each information block on the display means. For example, the manual should tell you where to find your decompression ceiling, and the information block that will tell you how much time you will have to spend there. It's not going to tell you what your decompression profile will look like. That would be like trying to tell you how far you can drive with an unspecified amount of fuel and an unspecified fuel economy.