Use a Computer or BT?

[Dr. Lecter]

lost deco gas is pretty simple. 1.5x the time and share your buddy's deco gas. I don't really see a need for special tables. Ymmv.

Ah yes, the 'this one weird [-]trick [/-]equation will probably work fine most of the time!' approach to deco. Perhaps you should consider skipping the contingency tables and just go with RD?

Whatever works for you, though. I'm no more interested in judging than I am in accepting others' stated approaches as canon.

 

[PfcAJ]

I don't mind ratio deco for some instances, especially really short bottom times and stuff I've done a bunch of times before.

Like you said, I could fill my wet notes with a bajillion permutations or print 3 pages that cover a wide range of likely situations. Some folks get in the water with too few printer options, IMO.

 

[Tortuga68]

Not really, bottom timers are great for any profile.

Yeah, computers suck

 

[lefrogster]

I think this kind of contingency planning is a great reason to use computers within a hard plan.

Lec, does your computer and software generated profiles match up? I could get deco planner and my Suunto HELO2 to get similar profiles only on Suunto personal preference P -2.

I've been doing this on my latest dives and think its a pretty good idea. I dive the table above all else; if the computer gives me less deco time (because my profile was more shallow) I stick with the table for more conservatism. But if the computer gives me more deco time, I follow that; basically I take the more conservative of the two.

 

[rongoodman]

Lec, does your computer and software generated profiles match up? I could get deco planner and my Suunto HELO2 to get similar profiles only on Suunto personal preference P -2.
.

Good reason to use a computer which runs a standard, non-proprietary algorithm, like VPM or Buhlmann-GF.

 

[Dr. Lecter]

Lec, does your computer and software generated profiles match up? I could get deco planner and my Suunto HELO2 to get similar profiles only on Suunto personal preference P -2.

I've been doing this on my latest dives and think its a pretty good idea. I dive the table above all else; if the computer gives me less deco time (because my profile was more shallow) I stick with the table for more conservatism. But if the computer gives me more deco time, I follow that; basically I take the more conservative of the two.

If I want them to, yes. I have SW computers with VPM unlocked and use V-Planner, but I'm increasingly using GFs on the SW to limit deep deco time because I'm finding that some of the assumptions about VPM (and low LO GFs with higher HI GFs) aren't working for me on the dives I'm doing. For a CCR dive where both my online deco and SA Petrel have failed but I can stay on the loop manually, I cut tables using the SW planners and bring them.

Planning for BO with no working computers is trickier. Sometimes I'll just plan BO using the SW's onboard planner, too, but for bigger dives I'll plan BO using V-Planner on a lower conservatism, fast bailout setting. It's easier to handle complex plans with the better interface and extra functionality, the additional deep deco time result in more BO gas being planned, and I'm happy enough with VPM to fall back on it if two SWs and my CCR go bad on the same dive. The VPM-FBO ascent profile will be different than the ascent profile I'd have used if my SW GFs were available, but for me it's a matter of preference rather than one being right and the other being wrong.

 

[Michael Guerrero]

I always find it curious how many people print such limited tables for their diving. 2 contingency tables is quite a small range of potential eventualities (deeper, shallower, shorter, longer, varying degrees of each of those variables). Also curious is that it appears that people re-do this process over and over.

My dives are pretty similar most of the time. I use the same set of laminated tables over and over again based on what dive I'm doing. I'm also not a cave or wreck pen diver, so for open water deco in predictable conditions these suffice. More dynamic dives would call for more contingency planning.

---------- Post added June 14th, 2014 at 08:11 PM ----------

"This computer has bugs. Although we haven’t found them all yet, they are there. It is
certain that there are things that this computer does that either we didn’t think about,
or planned for it to do something different. ....." [emphasis is mine]

Gee, was the marketing guy on sabatical !?! Somewhere in a dive shop:

Sir, you can choose between this technical dive computer over here or this buggy one. Which would you prefer? Ummm.... let's see, it's a hard decision but I'll take the buugy one!

I think it's a testament to Shearwater being a stand-up company. Every piece of software has bugs, and if you think your computer is perfect or bulletproof you are mistaken. Good on Shearwater for being up-front about the limitations of its (and any) piece of software.

 

[syntaxerrorsix]

I don't understand where the idea of downloading a profile to a dive computer is coming from. There was at least one dive computer, made by Cochran as I recall, that automatically switched deco gases in it's calculations, based on depth. This could cause big problems if the switch wasn't actually made, or was undesired, such as a cave dive in which the diver was temporarily forced shallow but then had to descend again. The Shearwater will change the color of the gas display to remind you to switch to a richer active deco gas if you haven't done so already when it thinks you should. When you have cleared a deco stop, the display will change to show the next stop, and time required.

They switch back after they figure you haven't died and continue to track the appropriate mix. Lost gas is a bitch so I'd leave one with O2 as deco gas and one with back gas.

 

[CarlGH]

It is finally time for me to purchase a new dive computer. My old trusty Suunto Solution Nitrox just died 2 days ago.

Up to now I used this for all recreational diving on Air & Nitrox. For mixed gas diving, I cut my own tables using software I've had for quite some time.

In any case, I'd like to get a decent computer that I can use as a rec/tec computer. I probably won't do many mix dives on it (yes, I am mix certified and also certified as a gas blender by IANTD), but I do have some dives that I plan to do in the 150-220 range that I will use mix on and there are several dives that I will be doing some Nitrox Deco on.

The local dive shop (I'm from Southern New Hampshire) is recommending either one by LiquiVision, or the Uwatec Galileo. Has anyone had any experience with either of these either positive or negative? And, what are the "sister" versions of these if any (I know there probably aren't any of the Liquivision, but the Galileo might have some). I am interested in the higher end versions but would like information on all levels of them.

Thanks,
Carl

 

[rhwestfall]

Carl:

Two words....

Shearwater Peterel