DIR Answer Required

[edparris]

Hey sorry for being dense but I don't understand how you guys execute ad-hoc dives with a computer. Take the following situation:

You're at 70fsw with 1200psi in your AL80 and your computer says you have 25 minutes remaining on your NDL. You see a really cool <whatever> at about 100fsw. Assuming it will only take a minute to descend how do you figure out how much time you can safely spend at that depth.

Would someone who uses a computer regularly explain their thought process to me? Do you start the descent and just keep a close eye on your NDL and SPG?

 

[JeffG]

Hey sorry for being dense but I don't understand how you guys execute ad-hoc dives with a computer. Take the following situation:

You're at 70fsw with 1200psi in your AL80 and your computer says you have 25 minutes remaining on your NDL. You see a really cool <whatever> at about 100fsw. Assuming it will only take a minute to descend how do you figure out how much time you can safely spend at that depth.

Would someone who uses a computer regularly explain their thought process to me? Do you start the descent and just keep a close eye on your NDL and SPG?

Short answer...take a DIR-f class

 

[PerroneFord]

70ft, 1200 pounds??? You're past your turn pressure.

 

[edparris]

Short answer...take a DIR-f class

Sigh I have taken a DIRF class (I even passed) and I understand how I would think through the problem. I was asking how the computer folks would think through the problem given their current training.

Lets see how someone else answers shal we eyebrow

70ft, 1200 pounds??? You're past your turn pressure.

Grrrr... no kidding really.... oh well so much for asking the folks a trick question.

 

[JeffG]

Sigh I have taken a DIRF class (I even passed) and I understand how I would think through the problem. I was asking how the computer folks would think through the problem given their current training.

Lets see how someone else answers shal we eyebrow

Ah...Its all clear to me know. Shhhhh...your hunting wabbits.

 

[PerroneFord]

Grrrr... no kidding really.... oh well so much for asking the folks a trick question.

DOH! Ask another one.. I won't say anything.... honest.

 

[Cacia]

well, I do know that I do not have the air to drop that far with only 1200 psi left. I don't need tables, a plan, DIR, or a computer to know that. Ya'll must underestimate me a wee bit. You are going to have to make your tricks better, buy pressure gauges, etc.

I have to be careful in here, because if you turn this into me answering your questions about how I do things...somebody will get mad. we can migrate out and you can test me, but not in here. In here we have to stick to the DIR way or the highway.

 

[ScubaMilo]

As usual Jeff is way to quick with the right answers.
And as usual I will have to agree with him.
Dives can be modified on the fly but certain limits have to be taken into consideration.
Wet notes are a useful tool when recalculation is necessary.
Must be very aware of MOD.
Must be fairly good with gas consumption calculations.
Must know the team your diving with is capable and willing to change the plan.
(remember if something happens to your ability to lead a dive i.e. broken bottom timer etc... they could end up leading you home)
But this being said nothing replaces good training.
You must be trained to do this type of deco on the fly or dive plan on the fly.
So to steal from Jeff again take a fundies class and a tech1 class.(once you have passed)
Then you will be properly trained and confident enough to attempt this type of diving without a computer.
Without proper training it will seem like a crap shoot, which it basicly is.(without training)

 

[onfloat]

Catherine,
Jeff gave the best answer Max depth is X; Max time is Y for that depth or turn pressure Z, all discussed by the team before the dive. When Y or Z is reached it's time to ascend. Perhaps when there is another SB lunch here on the island I'll stop by and you can beat me up.

 

[AaronR103]

If you understand your tables, and understand your profiles, the computer is simply a backup or sanity check. They are VERY nice for telling you your depth and runtime though!

This is a better phrasing of what I took away from the conversation with my instructor, and the point I was trying get across. Sorry for the miscommunication.

A