Do you use computer or tables for deco and trimix dives?

I've posted this question on a few other boards, but I wanted to post it here as well, as almost all of my diving right now is in the caves.

So the basic question is, if you own a trimix-capable computer, do you use it as your primary source for stop depths and times for deco dives (on trimix or otherwise), or do you cut tables and use your computer as a backup?

A point was made on another forum that the more multilevel profiles found in caves versus wrecks might lend themselves more to computer use. Any thoughts?

Just curious what tools you all are using and how. Thanks!

Brian

I spent a grand for a trimix compatable dive computer. I use the computer as the primary because of the multi-level profile potential that you speak of. A grand would be a heck of a lot of money to only use it as a backup. I cut custom tables as my backup.

Usually, my computer will not require the deeper stops required by the tables. So I start by stopping at the table's required deeper stops and then switch over to the computer when I hit its first deepest required stop. In the end, the computer and the custom tables aren't materially different in run times, even on trimix dives.

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Originally Posted by aw

A grand would be a heck of a lot of money to only use it as a backup.

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I agree, but it surprises me how many people do, or who bought expensive computers and then sold them to switch over to tables and a bottom timer. Could just be a vocal minority though - I'm very close to purchasing a trimix-capable computer myself, and have not found any good reasons NOT to use it. I plan on cutting custom tables as a backup, and I also plan on monitoring the types of curves my computer gives me for a good while though.

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Originally Posted by aw

Usually, my computer will not require the deeper stops required by the tables. So I start by stopping at the table's required deeper stops and then switch over to the computer when I hit its first deepest required stop. In the end, the computer and the custom tables aren't materially different in run times, even on trimix dives.

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So you don't find your computer "punishing" you for those deep stops? Not sure I'm allowed to ask, but do you mind telling me what computer you're using and what software you're using to generate your backup tables?

Thanks for the response!

Brian

I use Nitek He computer and V-Planner or Deco Planner software.

I'm no deco guru. It could add a few minutes, but it's nothing that really stood out.

One thing I enjoy about using a computer is being able to record the profile. Very useful for planning future dives.

Thanks aw - I appreciate the responses.

Brian

I was watching that thread on the other board and found it funny that it took something like 15-20 post before the first mention of ups and downs of cave diving. I too own the very expensive computer from the UK and I am getting ready to send it in for maintenence and upgrade. Then upgrade to trimix. I think for the cave diving world, most use the computer as primary and the tables for back-up. What do you do if you use tables :?: Exp. Lower Orange Grove, You make a short dip to 175 them spend most of the dive in 150-140 area. then dip again to exit. If you put this in a V-pl@ner it freaks about bounce profile. You also would have to cut contingency tables for all the depth segments....
It just makes sense to use the computer and then if you have to bailout to tables you use the max depth and pay the penalty. Now I dive with a guy on this board that uses tables all the time. Maybe he can chime in.
Do you Average your depth then calculate?

Just my 2 cents

You really need to analyze the final curve to accurately determine if deep stops are being penalized by your computer. With a Nitek 3 it initially shows me being penalized at deep stops, but once I get shallow the penalty is no longer there. I typically follow a plan with deep stops as generated by a VPM/B algo, and then finish out on my computer. This adds on extra time in the shallower stops (not too different from the standard algo of the computer without the deeper stops) as compared to following the table all the way out, but I see no need to get in a rush and I feel good after each dive.

There's nothing wrong with telling us which computer you use, what you like about it, or what you don't like about it. That's what this forum was established for. Rule number 6 simply prohibits statements such as, "Everything this company makes is great," or, "Everything that company makes is garbage."

Allen, I removed the asterisks in your post because they weren't necessary.

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Originally Posted by Sludge

"Everything that company makes is garbage."

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You forgot to fill in the company name... :-D

I agree with AW. I use a Hydrospace Explorer for primary deco, and tables for backup. On deep dives, I cut custom tables to cover the most likely potential profiles.

I use a HS Explorer also as my primairy and tables as a back up. Depending on the cave and the profile you dive can mean a big differance. Reember that if you have to go in 500 feet at a depth of 45 and then drop down to 150 then reverse that out. It is much harder for talbes to compute this. The swim time at 45 to 30 can burn off some time. On OW mix dives I use tables and the HS as a back up. SInce it is a square profile it is easyer for tables then a up down up up down levle then down then exit profile.

SLIM

Thanks SLIM, thanks Forrest. Do you guys mind if I ask why you chose the HS Explorer? Do all versions of the HS Explorer use RGBM?

Thank you for the responses!

Brian

(I just got a tattoo over the weekend, so it's going to be cyber-diving for me for the next couple of weeks, hence all the posts... I'll shut up once I can dive again!)

At the time I got mine, it was the best thing out there. It might still be, I haven't compared it to the newer trimix computers lately. All HS Explorers can be upgraded to RGBM.

I dove tables for years and used a VR3 as backup. I have enough confidence and experience with it now that I dive the VR3 and take tables for backup. I recently upgraded to the VPM algorithim on the VR3 that I use as primary and cut V Planner tables for backup.

A few years ago I tried the Nitek He but did not like deco profile on deep hypoxic mixes.

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Originally Posted by jpdiver

I dove tables for years and used a VR3 as backup. I have enough confidence and experience with it now that I dive the VR3 and take tables for backup. I recently upgraded to the VPM algorithim on the VR3 that I use as primary and cut V Planner tables for backup.

A few years ago I tried the Nitek He but did not like deco profile on deep hypoxic mixes.

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I've heard the VPM upgrade on the VR3s is conservative compared to VPlanner. Have you noticed any glaring differences between the two?

Brian

Just my 2 cents worth. I use both. A computer and a bottom timer with depth and tables. I like redundany. The computer gets the first nod because you deco at real time depth and time. Tables are the best guess. Cindy :)

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Originally Posted by brianstclair

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Originally Posted by jpdiver

I dove tables for years and used a VR3 as backup. I have enough confidence and experience with it now that I dive the VR3 and take tables for backup. I recently upgraded to the VPM algorithim on the VR3 that I use as primary and cut V Planner tables for backup.

A few years ago I tried the Nitek He but did not like deco profile on deep hypoxic mixes.

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I've heard the VPM upgrade on the VR3s is conservative compared to VPlanner. Have you noticed any glaring differences between the two?

Brian

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The VR3 is a little more conservative than V Planner. I believe that Delta P uses Eric Baker's V-Planner program so I don't know the reason. I assume the conservatism settings don't line up. The biggest difference is when using a 0 setting. As you increase conservatism, the difference lessons. It is not glaring however. a 25 minute dive at 190 feet on mix, is a difference of 3 to 5 minutes of deco in CCR mode. V-Planner is perthaps a bit agressive so the extra conservatism in the VR3 is probably not a bad thing. I may email Delta P and ask them.

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Originally Posted by Cindy

Just my 2 cents worth. I use both. A computer and a bottom timer with depth and tables. I like redundany. The computer gets the first nod because you deco at real time depth and time. Tables are the best guess. Cindy :)

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Ditto.

However, I'm in the market for a used VR3 with B&W screen. Open circuit and trimix enabled. Computer upload cabling and software. Anybody selling one that fits this description?