Split from Exploration dives without a computer

[Thalassamania]

The post you quoted was in response to someone pointing out that your answer was not DIR. At the time, the original poster had asked for DIR answers. That's irrelevent in this thread now.

It seems to me that "someone" was you.

 

[Snowbear]

It seems to me that "someone" was you.

No. My post was a response to onfloat's post, who responded to your post when it was still in the DIR forum..... back before the thread was split. The thread was split to preserve the posts, including yours, which are not allowed in the DIR forum.

 

[MXGratefulDiver]

So divers who are not Trimix certified cannot diver deeper than 100 feet?

Of course you can ... you just can't claim that it's "DIR".

Does that really matter?

... Bob (Grateful Diver)

 

[onfloat]

I use a old Genius, because it is accurate down to 100 psi

Can I ask, when was the last time you had it calibrated? Calibration on a guage is usually only good for about 3 years and that's one is not regularly getting knocked around. It is generally presumed that the upper and lower 10% has the greatest amount of error, so on a 0-5000 psi anything below 500 and anything above 4500, unless you are paying big dollars for the gauge.....

 

[onfloat]

No. My post was a response to onfloat's post, who responded to your post when it was still in the DIR forum..... back before the thread was split. The thread was split to preserve the posts, including yours, which are not allowed in the DIR forum.

Yep, she was just reminding me that I left a few things out that really don't matter here in this forum.

 

[onfloat]

ok, onfloat. The place where you did your last class, lets skip the name. Those guys take divers on air to the Sea Tiger everyday and they are the local DIR shop, I just was trying to figure out how thay do all the things they do and still .... see? I am not trying to make a problem it is just that every "DIR" diver I have ever known has one set of what they "say" and then they either solo, or use computers, or take divers that have 10 dives to very deep dives on air as part of their business/income model. I do not want to discuss said shop, but I am laying out an example I know you can follow because I think this is the real mystery to people like Dennis and I with DIR in general. I know PADI is much worse so I am not being critical. Just trying to "get it". There are certain things I want from DIR divers.

Having said that, I wish divers experienced with thinking the tables through on every dive and making adaptations for multilevel, changing dive plans would explain the nuts and bolts of how they do this like what has happened in this thread and the "mother thread" as SB, Thal, Onfloat, jeff have done. Even Charlie's 100 psi per 10 is very helpful and frankly, I have never heard this before. I know it because I do it...but the "news you can use" angle does not happen enough around here and I wish there was more of this. Even if you disagree with someone's approach, I still learn quite a bit from a guy who decides to run an excel spread sheet and demonstrate how he thinks his planning through.

Catherine, I know you don't want to talk about that shop, but I really don't consider them DIR myself, just the closest thing we have on the island. They are in it to make a buck and providing a service. If I stuck to strict rule 1, I would never get to dive while I'm here. I just prefer to modify it to "not with unsafe divers" and discussing the plan before we hit the water.

 

[onfloat]

onfloat, what does your math look like that tells you .21 O2 increase to .32 gives a 20% increase in depth? I know you are right, I just want to be able to calculate...say .36 EAN depth advantage in my noggin.

Cathrine, it's all about limiting the nitrogen exposure. At 1 ATM you have a 21:79 split on air and 32:68 split on N32. So at 4 ATM (100ft) you have a nitrogen partial pressure of 3.16 on air and 2.72 on N32, which is like diving at 80 feet on air,(20% difference). Hence you can stay a little longer at that depth. Take a look at the tables and compare the times and you'll see the pattern.

 

[Thalassamania]

Sometime in January. An advantage of having close ties to an Oceanography instutute is easy access to reference grade instrumentation, calibration pumps and deadweight testers.

In addition I've scavenged several digital gauges with different atributes, including a 5000 psi +- 50 psi and (because I'm most interested in low end errors) a 700 psi gauge that's +- 2 psi.

I routinely check depth and contents guages yearly or prior to major operations.

 

[*Floater*]

Sometime in January. An advantage of having close ties to an Oceanography instutute is easy access to reference grade instrumentation, calibration pumps and deadweight testers.

In addition I've scavenged several digital gauges with different atributes, including a 5000 psi +- 50 psi and (because I'm most interested in low end errors) a 700 psi gauge that's +- 2 psi.

I routinely check depth and contents guages yearly or prior to major operations.

Thalassamania, how do you go about checking SPG accuracy? I have a few Sherwood brass SPG's and one DIR Zone brass SPG, I'd like to check how accurate they are but don't have specialized equipment. Any suggestions? Which brands do you find most accurate?

 

[TheRedHead]

Of course you can ... you just can't claim that it's "DIR".

Does that really matter?

Just curious as to where GUE stands on deeper dives with air? I take it EAN32 is ok?