Buying my first Dive Computer need a little help

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I currently own a Puck Pro. I am no expert by any means I hit 23 dives this past weekend while getting my Advanced Open Water. I do wish I would have spent a little more on a computer though.

Pros:
-Great ease of use
-Holds 25 dives (bought the cable and syncs with MacDive great)
-Shows depth, average depth, temp and all the basics I use at my level

Cons:
-Would love a wireless air transmitter option
-Wish the display was brighter with the light
-No Compass
-Single button can be annoying sometimes (double edge sword with ease of use, overall not bad)

None of the cons have been deal breakers so far. I can admit if I could add 2 things it would be wireless air then compass. I did not realize how nice it would be to have the air reading just as a easy glance feature but always to log my air usage and see what differences I am having a s I progress as a diver.
 
Stuff you might want which some entry level computers surprisingly lack:

Average depth - so you can calculate gas consumption.
Logging for more than a handful of dives - so you can be lazy about writing up your log book.
PC downloadable logs - so you can star at graphs and wish you could hold stops better.

If you can download your dive log to a laptop/desktop computer, then the computer software (I use Subsurface, which is free and works very well) will tell your average depth. If you have AI, then it will also tell you your SAC on a moment-by-moment basis all the way through the dive, plus your average SAC for the whole dive. If you don't have AI, you can enter your start and end pressures and it will still tell you the average SAC for the whole dive.

I have never consulted "average depth" on my dive computer. I'm not even sure whether either of my computers displays that. Probably, but I don't know.

Multiple Gasseses?

My tank has never been close to empty. Why do I need to know my SAC? Who really cares? Why do you think you need all of this stuff?
Please explain what problem each of these metrics solves?

He explained that knowing average depth lets you calculate your consumption rate. And knowing your consumption rate will let you plan a dive - if you so choose. I don't think it's a bad idea at all, even for basic recreational dives, until you have an experience base to, essentially, "know" what your consumption and bottom times will be like.

I agree with you that multiple gases on a recreational computer are total marketing hype.

To the OP: I seem to be ever the contrarian on the subject of computers for new divers. I was where you are 2 years ago. One of my earliest posts here on SB was about the Hollis TX-1 and the merits of going with that for a first computer. Almost everyone that bothered to reply gave me some kind of answer that fell into one of two categories: One, "that is way too much computer. Get something cheaper and simple." Or, two, "if you're going to buy a tech-capable computer, get a Shearwater Petrel." Almost everyone (but definitely not EVERYONE) said that AI is useless.

Being a newb who tends to question everything but then follow the advice of the experienced folks, I ended up not getting the TX-1. However, I did somewhat ignore some of the advice in that I did go with a wristwatch-sized computer with a wireless AI transmitter.

Now, in short, almost 2 years have gone by and I have advanced to the point of getting my first tech diver certifications at the end of this past April, and have been doing tech dives since. I bought and later sold a Petrel 2. At this point, looking back and assessing, I love my AI. I have used it on every recreational dive I have done and have now moved the transmitter to my tech diving reg set and use it to monitor my tank pressure and collect consumption data even on tech dives. My primary computer is a tech computer (but no longer a Shearwater) and my backup is the Rec computer (with Gauge mode) that I bought after listening to all the posters here. And I am back to shopping for a Hollis TX-1 to replace my Rec computer as my backup to my primary tech computer. So, if I had gone with my own research and instincts from the beginning, I would have gotten a Hollis TX-1, still be using it, and not be looking to replace it. Instead, I am still using my first computer and I have been very happy with it. But, it is not trimix-capable and that is the direction I'm heading now, so I want to replace it.

Many tech divers here have a mantra of "two is one. One is none." But then they dive with only 1 computer and use a written plan and/or tables as their backup. I am firmly in the camp of having 2 computers on every dive - for many reasons. 2 computers is good on recreational dives, but it is even better (to me) on tech dives. And I don't mean a computer and a bottom timer (i.e. a computer operating in Gauge mode). I mean two computers operating in Dive mode. Just my opinion, of course. All the reasons for using a computer at all are the exact reasons I want a computer I can use if my primary computer croaks during a dive. PLUS the ability to sanity check one computer against the other.

Also, with Recreational Trimix being a viable option now, I think anyone looking at new computers should at least make their own evaluation on whether they want their first computer to be trimix-capable. Some agencies that certify new divers won't even certify you to dive below 100' without using Helium. Others will certify you to 130' with air or Nitrox. Regardless, being a recreational-only diver and using Helium is now a very realistic possibility (though, not common, of course - and with Helium prices being what they are, not likely to become very common).

Bottom line: Avoid anything with an algorithm that is too conservative. One of the most common reasons that computers are for sale in the Classifieds is that the person found it to be too conservative. OTOH, you virtually never see a computer for sale because it is not conservative enough. Likely candidates for too conservative would be anything from Suunto or Cressi - just as examples. If you really think you might go tech at some point, then give some thought to getting something that will be really useful in tech. I.e. a computer that supports (at least) the Buhlmann algorithm WITH Gradient Factors (i.e. not just some computer that uses a "modified Buhlmann" or "based on Buhlmann" algorithm. That computer will almost certainly either support trimix or be upgradeable to support trimix, but IF you go that route on a computer you should confirm that it has or will let you add trimix support (i.e. set a percentage of Helium, in addition to setting a percentage of Oxygen). Then, with those criteria, get whatever appeals to you.

Here is a good read (with a lot of info on different models and their relative conservatism):

So you want to buy a new computer?
 
This, "buying my first computer" thread, is one on the most common on SB. I agree with @stuartv on one very important variable, do not buy a computer that is so conservative that you will later have to upgrade to a more liberal decompression algorithm. Most of the RGBM algorithm computers are quite conservative, Cressi, Mares, Suunto. Atomic Aquatics is more liberal. For most recreational divers, I would suggest an Oceanic, dual algorithm, computer. The DSAT algorithm is at the liberal end of the spectrum and the PZ+ algorithm is middle of the road. The OEM of Oceanic computers, Pelagic Pressure systems, was purchased by Aqua Lung, their computers run only PZ+ and not DSAT. Folks have mentioned the Veo3 and Geo2, both fine computers. I have been diving a Geo2 as backup for 5 years, 650 dives, with flawless performance.The Veo2 would probably also meet your needs. Discount pricing is often available, LeisurePro, for example.

Best of luck in your computer purchase

Good diving,

Craig
 
Bottom line: Avoid anything with an algorithm that is too conservative. One of the most common reasons that computers are for sale in the Classifieds is that the person found it to be too conservative. OTOH, you virtually never see a computer for sale because it is not conservative enough. Likely candidates for too conservative would be anything from Suunto or Cressi - just as examples.


In the context of the Basic forum where this post resides...

Let me correct you on this (again)

SOME computers from Suunto are more conservative than others.

And while I know there are some on here who love to make blanket statements, I can assure you from ACTUAL EXPERIENCE rather than repeating stuff they've heard or read, that my Suunto will give me a similar deco obligation to my buddy diving an OSTC.

I will also share the experience where on Dive 1 or a trip one diver made a 40 min dive to 22m on a conservative computer, didn't exceed any parameters (NDL, fast ascent rate etc) and still spent the night in a chamber!


Further more I will share a quote from @DevonDiver Which IMO should be pinned

"Safety factors, in my opinion are under-utilized by most divers. That's because they limit dive times. Nobody like their dives cut shorter than necessary.

Personally, I apply safety factors/algorithm conservatism based on the existence and/or severity of known DCS predisposing factors. It's a decision I make before each dive, based on my body, vitality and health at that time.

If I am moderately tired, a little dehydrated, a small injury etc... I will go to SF1. If I'm really tired, noticeably dehydrated, a significant injury... then I would go to SF2. And so on"


The reason (IMO) that manufacturer s make the so called "conservative" computers, is that newer divers, don't have the knowledge to be able to decide to make informed decisions about the deco algorithm type and settings. Sure by the time the diver gets to the advanced stage with much more experience and knowledge they are (hopefully) in a position to choose a computer and fiddle with the setting to their hearts content (hopefully) knowing what the implications of such might be.
 
SOME computers from Suunto are more conservative than others.

Conservatism is a really, really good idea for novice divers. An aggressive computer can empower them to conduct diving schedules that pose an unreasonable risk of DCS. With experience comes a better understanding of the consequences and implications of the diving you opt to carry out. Only then, might a conservative algorithm become frustrating.

The good thing about RGBM model is that it imposes mandatory conservatism as an automatic calculation where certain risk-inducing dive behaviors are present. The risk-inducing behaviors are characteristic of how many inexperienced 'vacation' divers approach diving.

That behavior being to go away somewhere warm and do the most diving that they can fit into the very limited time they have available. So there's intense multi-day, repetitive diving... with short surface intervals... and occasional faster than optimum ascents.

RGBM amends it's algorithm when those factors apply. It's good because those divers are unlikely to start cranking up conservatism for themselves.... they are, after all, in a pursuit to spend the most time underwater that they can.

decompression-algorithm-rgbm.jpg


Of course... more advanced, knowledgeable divers don't need a computer model that unilaterally applies prudent safety factors for them.

Those advanced divers know better than to push the limits too hard. Right?

After all, RGBM doesn't really get that conservative unless you're diving really aggressively... or doing newbie stuff like fast ascents.

An advanced, knowledgeable diver would assessing their diving behavior and risk factors... and be manually increasing their conservatism on another computer/algorithm that didn't do it for them automatically. Right?

You wouldn't even notice the RGBM model acting conservatively if you dived conservatively, prudently and skillfully from the outset. And if you weren't diving optimally, you'd use the conservatism settings to compensate....

Another way to express it would be... "if you're prone to diving like a lunatic, then an adaptive dive computer algorithm that moderates your lunacy is probably a great idea".
 
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In the context of the Basic forum where this post resides...

Let me correct you on this (again)

SOME computers from Suunto are more conservative than others.

Where is the correction? I said:

Likely candidates for too conservative would be anything from Suunto or Cressi - just as examples.

No REASONABLE person would take that as "all Suuntos are too conservative." A reasonable, intelligent person would take that as a statement that all Suuntos are CANDIDATES to be considered too conservative. The person buying the computer should evaluate any computer they are buying for themselves to decide if it's too conservative for them.

A new diver might be well-served to dive more conservatively. Does that mean you think they should buy a really conservative computer and then, say, 6 months later, buy another computer once they've got some experience and found their first computer to be more limiting than they would like? Or should they buy a computer that will serve their needs for the foreseeable future and, perhaps, bump up the Conservatism Factor to start, so they are diving more conservatively at the start of their diving career (and maybe forever), but have the option to relax the conservatism and get longer NDLs, when they decide they are ready?

Are you now going to give me the tired old argument of "when you get to the point of needing a better computer, the cost will be a drop in the bucket compared to everything else you have to buy"?

Listening to people like you is why I have now been diving less than 2 years, have bought 3 computers, sold 1, and am looking to buy a 4th, to replace my very first one. If I had done what made sense (as I've explained in my previous post) from the beginning, I would have bought 2 computers by now and have no reason whatsoever to be looking to spend money on a 3rd.

I also note that the first computer I was seriously looking at, the Hollis TX-1, has a max GF Hi and Lo setting of 90. So, the most liberal setting on that computer is GF90/90. And that is more conservative than the Oceanic DSAT algorithm*. So, if I had not listened to folks like yourself, not only would I have spent less time and money buying computers, I would have been diving more conservatively than I have been with my Oceanic computer with DSAT which I bought instead.

* statement based on two things: Comparing dive profiles using Buhlmann w/GF in Multi-Deco against NDL tables in the Oceanic Atom manual. And, comparing my Atom against my SeaBear H3 (Buhlmann w/GF) on actual dives.
 
@stuartv

Really!?! You say first "Anything from" and then try to back track by saying "No REASONABLE person would take that as "all Suuntos are too conservative."

Whatever....

I was just pointing out a correction, and in the context of this being a basic discussion.

You should be aware that I never ever recommend a specific brand or type. I endevour to give people options and information from which they make their own informed choices. So your comments above are disingenuous at the least.

I dive possibly the most unpopular Computer on SB the Eon Steel, I wasn't swayed by the Petrel Fanclub I looked at all the options and weighed up what was best for me. I don't care if it's not right for everyone else. And I don't care if people don't like AI

You on the other hand clearly don't .. The fact that with only 2 yrs of experience, and not much more than 100 dives (mostly under training in confined waters such as quarries) are looking to buy their 4th computer speaks volumes about you rather than the advice given on the board.

And yes "the tired old argument of "when you get to the point of needing a better computer, the cost will be a drop in the bucket compared to everything else you have to buy"? is still valid.

To take this to extremes I'm looking into rebreathers, so if I take the buy once cry once standard it would have been better if I'd have brought one to do my OW with rather than having $1000's of gear some of which will be redundant or not needed as well as having to learn to dive again? Which is where your argument stems from
 
Conservatism is a really, really good idea for novice divers. An aggressive computer can empower them to conduct diving schedules that pose an unreasonable risk of DCS. With experience comes a better understanding of the consequences and implications of the diving you opt to carry out. Only then, might a conservative algorithm become frustrating.

Another way to express it would be... "if you're prone to diving like a lunatic, then an adaptive dive computer algorithm that moderates your lunacy is probably a great idea".

I agree with the last part of your post, I'm just not sure it applies to most novice divers. Many of those are actually less aggressive divers, and limited by poor air consumption. I've seen a lot of recreational divers become more aggressive as their (false?) confidence increases and air consumption lowers.
 
I have two of the pre-93 Aladin Pro Air computers. I like them for simple air dives. The uncluttered display really works for me. Sometimes I will keep the Uwatec on one arm and my Nitrox computer on the other. I like the simple readout, but also don't want to completely give up the advantages given to me by either of my Nitrox capable computers. If I was in an area where Nitrox was not convenient, I would probably be using the Uwatec Aladin Pro nearly all the time.
A few of my Aladins are nitrox capable, a few are not.
 
https://www.shearwater.com/products/teric/

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