Buddy diving on their computer

[Blackwood]

The author of this quote, RSTOFER goes on to give good advice -- if you want to know more about deco, read the books. BUT, "exactly the maximum allowed" -- PLEASE -- there is NO "exactly" in any decompression!

Exactly per the model.

 

[rstofer]

The author of this quote, RSTOFER goes on to give good advice -- if you want to know more about deco, read the books. BUT, "exactly the maximum allowed" -- PLEASE -- there is NO "exactly" in any decompression!

The "mysterious malady" is just that -- mysterious.

Back to the OP -- dive conservatively and have fun.

Yup! Exactly was a poor choice of words. Probably best to omit it.

Richard

 

[Coldwater_Canuck]

Isn't that exactly what the tables do?

The NDL is exactly the maximum allowed nitrogen exposure for a given depth. The fact that it varies by depth indicates that various tissue types are limiting the dive time.

No, the tables tell you everything in terms of time, not risidual nitrogen number.

Whats the difference? Look at a table, tell me the surface interval I need if I just spent 20 minutes at 80 feet, 20 minutes at 60 feet and 20 minutes at 40 feet and want to do a second dive with 20 minutes at 60 feet, 10 minutes at 50 feet and 10 minutes at 40 feet? (Note: I just made up numbers, they may be above NDL limits, that's not the point). Try doing it with tables: it's possible, but not very intuitive or quick

Now compare that to being given a list of the residual nitrogen at each depth: (numbers made up): take the number at each depth and multiply by time at depth. Then you can figure out pretty easily how long it will take for the nitrogen to wear off to an acceptable point (this sounds a bit complicated as well, but with a calculator it is very simple).

Thinking about it and after typing that, I understand why they don't want to include that. But before I got a computer I would have appreciated it. There were a couple of times when looking at it at a "lower level" (the numbers behind the table) would have simply been easier for me.

 

[Blackwood]

20 minutes at 80 feet, 20 minutes at 60 feet and 20 minutes at 40 feet... (Note: I just made up numbers, they may be above NDL limits, that's not the point)

Yah. That first dive alone is marginal even on Navy tables.

There were a couple of times when looking at it at a "lower level" (the numbers behind the table) would have simply been easier for me.

Somehow I doubt that. There is an array of data going into each number. Your profile says you were trained by PADI, and I believe that PADI's RDP is a 16 compartment algorithm. So for each depth there are 16 compartments being 'tracked.' And they aren't just multiplying some constant by time. They're running exponential growth and decay (for all 16 theoretical compartment half-lives). So the numbers behind the table is a series of is a differential equations.

Everything you could hope to know about your dive tables: http://archive.rubicon-foundation.org/4228

 

[dpaustex]

DO NOT SHARE A COMPUTER. EVER!!!

You have no idea how much you are endangering yourself. You need to dive the tables, period.

In terms of air consumption, it all has to do with burning calories. If you're bigger than she is, you're going to hoover down more air. If you're swimming more, ditto. If you're colder, ditto.

But please, PLEASE, do not try and share a computer. That is one of the biggest no-no's around, due to a lot of factors. You should both be diving the tables. You have to dive the most restrictive of the team (the tables are more restrictive).

 

[Web Monkey]

Computers are great. Until they crap out. Smart divers check their tables before the dive, write down the info, and may well bring the tables with them in case the dive plan changes and can recalculate on the fly. Be a smart diver. Always.

It's a nice thought, but there's no way to accurately map a multi-level dive to a table built for a square profile.

If you dive a computer and it fails on a no-deco dive, the dive is over and you surface. If computer failure is a significant problem, I would recommend either a more reliable computer, or tables, a depth gauge and a watch.

Terry