Dive by computer?

[DevonDiver]

How do u keep track of letter groups once you're off tables? Just assume your in the last group before your SI?

If the bottom time & depth are within table/wheel/eRDPML limits, then you're good to go. Just calculate the dive in hindsight to provide you with your surfacing pressure group. Plan subsequent dives using normal tables/planner procedures.

If the dive has taken you beyond the limits of the table/wheel/eRDPML then you can't plan further, because you won't have a pressure group surfacing from the dive (you'll be in deco from the table's perspective).

If you own some decent dive planning software (V-Planner etc), you might find that you can plan the dive in hindsight using that. If you've multi-leveled and finished the dive with an extended safety stop (play in the shallows), then you may be able to account for any software deco (imposed where the software plan doesn't quite match your actual dive) and calculate subsequent dives using that software..

When diving with a computer... it's always a good idea to cross-reference the computer plan against a table/software plan. If your computer led dive can fit within a table based workable plan, then you're always gonna be good to go should your computer die.

 

[Diver0001]

How do u keep track of letter groups once you're off tables? Just assume your in the last group before your SI?

You can't. It's like having two maps of the same place but on different scales. You can't make them fit together.

In practice if you want to switch back to tables after using a computer for several dives (or visa versa) then you should wait 24 hours.

R..

 

[squid509]

If you own some decent dive planning software (V-Planner etc), you might find that you can plan the dive in hindsight using that. If you've multi-leveled and finished the dive with an extended safety stop (play in the shallows), then you may be able to account for any software deco (imposed where the software plan doesn't quite match your actual dive) and calculate subsequent dives using that software..

is the new DivePal program good for dive plaing
im not sure how good it is

 

[Brandon]

Here are my observations:

• Average depth of this profile (as stated by the OP) is approximately 42'.
• Profile is barely doable on air. At the end of the 50' segment, most computers will be running out of no deco time. You're 1 minute from deco with a Suunto Vyper, for example.
• Profile is much more manageable with EAN32.
• This dive will realistically be limited by available gas for a single tank diver with EAN32.
• This dive is a poster child for the benefits of nitrox.
• This profile requires an uncommonly good SAC (<.35 cf/m), assuming the diver is using an Aluminum 80.
• Even so, at the end of the 50' segment, there is 750psi of gas remaining. You would surface with 400psi.

It's really pushing it, but possible.

I wouldn't encourage a new diver to plan a dive in this manner...

-B

 

[g1138]

I'm not assuming, I'm asking haha.. And mainly because you said at the end of the day you work out your pressure group, but also said sometimes you're off table. So was trying to understand what you do, as it relates to some recent questions I've had

I know, I'm just saying for future reference: don't assume your letter group.
I slightly mistyped in my original post (It's corrected now), I meant to say that after EACH dive I write in my log book and calculate my letter group.
If I go off the tables then I stop looking at them for the rest of the day.

I won't pull them out again until 24hours after my last "Off table" dive.

 

[DiveNav]

......DiveNav - what is the tissue loading look like at the peak of the "hump" in the NDL profile?

Using Air peak is 86%.
See image

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[DiveNav]

is the new DivePal program good for dive plaing
im not sure how good it is

The Basic version is free ... and available here ..... see it for yourself

 

[wausman]

Here are my observations:

• Average depth of this profile (as stated by the OP) is approximately 42'.
• Profile is barely doable on air. At the end of the 50' segment, most computers will be running out of no deco time. You're 1 minute from deco with a Suunto Vyper, for example.
• Profile is much more manageable with EAN32.
• This dive will realistically be limited by available gas for a single tank diver with EAN32.
• This dive is a poster child for the benefits of nitrox.
• This profile requires an uncommonly good SAC (<.35 cf/m), assuming the diver is using an Aluminum 80.
• Even so, at the end of the 50' segment, there is 750psi of gas remaining. You would surface with 400psi.

It's really pushing it, but possible.

I wouldn't encourage a new diver to plan a dive in this manner...

-B

I should have stated I was diving EAN32 on this dive. After getting home and downloading the dive My SAC was 40 according to SmartTRAK. I was also at a 15' to 20' depth for a little longer then I thought. I posted this while I was at work and didn't have the profile right in front of me. I started the dive with 3100psi and ended with 400psi. I know what everyone is going to say but by that time I was in probably 15' of water and 20' from the shore.

As for me planning a second dive I have a dive planner right on the computer. I also carry two computers UWATEC smart tech and UWATEC air Z.

 

[Thalassamania]

You can't. It's like having two maps of the same place but on different scales. You can't make them fit together.

In practice if you want to switch back to tables after using a computer for several dives (or visa versa) then you should wait 24 hours.

R..

I already supplied a well tested method for switch back to tables after using a computer for several dives. Since you can not input a residual nitrogen level to any computer I know, going to computer after using tables is impossible; though I'd say that a 24 hour wait is absurd. If you needed to do it quickly, two hours of surface breathing oxygen followed by upping the computer to its maximum conservative setting should suffice.

 

[Brandon]

I should have stated I was diving EAN32 on this dive. After getting home and downloading the dive My SAC was 40 according to SmartTRAK. I was also at a 15' to 20' depth for a little longer then I thought. I posted this while I was at work and didn't have the profile right in front of me. I started the dive with 3100psi and ended with 400psi. I know what everyone is going to say but by that time I was in probably 15' of water and 20' from the shore.

As for me planning a second dive I have a dive planner right on the computer. I also carry two computers UWATEC smart tech and UWATEC air Z.

Yup - dive works best on Nitrox, and if your planning was such that you could ensure you were back at your entry point when you were nearing 500psi, it's a reasonable dive as well. There's also sufficient gas available throughout your profile to allow for a safe ascent to the surface, even assuming you had an issue and needed to share gas with a buddy.

I didn't mention repetitive dives in my first post, but with 1:30 surface intervals (and continued use of EAN32) you could easily do 4 repetitive dives with the same depth profile if you shortened the run time by 10 minutes, ideally on the long 50' segment. You could probably do more than that, but from experience it's extremely difficult to fit more than 5, 75-85 minute dives into one day.