Do you need computer at all?

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My LDS just became a Shearwater dealer, and I have to admit it's a very nice looking computer. What do you see as the advantages? Pretty much anything I move to is going to be an upgrade to my Gekko :D but I want to not be buying a top end computer twice.

IMHO the advantages of the Predator over the X1 are that it has a user replaceable battery ,a larger screen and its cheaper.

I'm sure they are both State of the Art Trimix computers. By all accounts they both work extremely well and have exceptional customer service.
 
Trimix equivilant narcosis depths are not taught in the first TDI deco procedures course -- kind of because it's an air dive to no greater than 150'.

So, I apologize for being a beginner who is just starting out in tech diving and hasn't taken trimix courses yet. All I was noting is that in the course I took there was a choice between computer and bottom timer+depth gage.

Should I PM you for permission to post a comment in the future? Or are beginning tech divers just not welcome here?
Sure, feel free to PM me before posting and I'll sign off on it.

In all seriousness, none of us are saying anything about you not having trimix...we're saying choose appropriate END's for your dive, or choose appropriate dives for the gas you have available.
 
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I wouldn't recommend buying a computer *before* an introductory tech course - what you (should) learn in that course is the information that will enable you to make a choice, between a computer and/or a bottom timer.

For an introductory course, a "recreational" computer in gauge mode is perfect. What you are really doing in the course is demonstrating that you have the skills to do a moderate amount of deco - the dives you do after the course should be fairly conservative and "routine", so a bottom timer and tables really should suffice.

Computers are a tool, and like all tools need to be "fit for purpose" and also "properly used" in order to do the job they are intended to do. Sure, you can work wood with a flathead screwdriver - but you'll get a much better result if you use a chisel.

There are two issues to consider. First of which is whether the computer is barrier to learning principles. Jumping in and following a computer is easy - when it works, but if you learn the computer rather than the principles of decompression, then (a) you are probably limiting your diving and (b) what do you do when something goes wrong.

Personally, I have major issues with the use of any computer that doesn't let you plan your dive in it's entirety. Yes, you can cut some tables using Vplanner then do the dive using a Suunto - but the Suunto won't give you the same profile as Vplanner. So if Vplanner says to stop at 21m, but the Suunto is saying 9m.... what do you do?

No offence intended to those people who use Ratio Deco 100% of the time - but I think that you've forgotten what it's like to start using RD. I think for RD to "make sense" and to make reasonable decisions about your profile then you need some form of baseline. For experienced divers that baseline can be the 100s of dives you have done using RD - but for newer divers, that baseline is probably some custom tables cut from desktop planning software. As a relative newbie to using RD, I still start with Decoplanner and compare what RD gives me for my plan and contingencies with profiles generated using VPM and Buhlmann and create some pragmatic profiles that suit my dive.

At present, I use a number of computers and/or RD - depending on the dive. I've used Suunto Vytec, VR3, Shearwater Pursuit and an OSTC mkII. I am using my OSTC almost exclusively now on both recreational and technical dives. On some dives, I still use my Vytec in gauge mode as the primary took and run the OSTC next to it "for information". This is because (a) I am geeking out, and (b) it's an experimental computer and I am wanting to see what it does under certain dive profiles.

The nice thing with the OSTC (which applies to the Shearwater as well) is that it can be set up to essentially mirror a RD profile. For OC diving, the OSTC is probably better featured and better value than the current Shearwaters - but the OSTC is to all intents and purposes entirely experimental, so it is not for everyone.
 
I am planning to learn tech diving in the coming future and I am now looking at the equipment that I will need for budget planning. Which dive computer do you guys mostly use? Someone says you need a bottom timer only and plan the dive ahead and then follow the plan. How many of you do not dive with a computer?

You're asking two completely different questions.

One is do you need a computer and the other is how many do not dive with a computer.

You "need" a dive computer like you need a car A/C or cruise control or a DVD player or heated leather seats.

I dive with a computer because it maximizes my dive time and significantly decreases my task load so I can spend more of my dive enjoying it and not thinking about the numbers.

I'm so far away from dive planning and calculations at this point that I just turn on my AI computer and jump in and when it beeps at me that I got 10 minutes left I start making my way back to the anchor line.
 
My LDS just became a Shearwater dealer, and I have to admit it's a very nice looking computer. What do you see as the advantages?

- The Predator is larger, which is both positive and negative. Both are readily visible in all light conditions.

- The Predator has a user changeable battery, which I prefer and it's very efficient with a low battery drain.

- If you are using it with a CCR, it has the capability to monitor external PO2 for 3 cells which is nice.

- It is less expensive than the X-1, but I suppose that this depends upon the configuration you require.

- The Predator uses the Buhlmann ZHL-16C algorithm (which I like) with open-source software; which is readily downloadable free of charge, so you don't have to purchase software from a 3rd party vendor. That said, V-Planner (X1) is a wonderful program.

- Both are made in Canada by Canadian companies, so that's a benefit as well. :D

- Service is apparently excellent from both companies.

Thats a few things off the top of my head. Good luck with your choice!
 
A question: if being conservative is important, would the more conservative approach be to use 10' increments? You are going to end up doing more time on stops if you use 160' for your 152' dive than if you use 155'.



If you read the V-Planner FAQ they recommend using their conservatism setting over padding time or depth. I do not remember why but there was a post from Ross on why either here or at the TDS. With that said there is not much of a difference in 155’ and 160’ and using either on a 152’ dive would be fine. In fact the mobile version on my phone only has 10’ units.
 
To get back to the OP's specific question. In the TDI deco procedures course I took this spring, the required equipment was either a depth gage and bottom timer OR a computer. I'm not certain that I would dive without a computer personally -- the warning signals provide a handy in-flight sanity check in case of mild narcosis. As a beginner I have a sense that I'm safer with the computer than without -- even if that is not really the case.

Just make sure you do not turn your brain off and let the computer do all the work this can get you in trouble. :)
 
The only computer that you realy need is the one between your ears.
 

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