First Dive Computer

[scrane]

So you ignored the Suunto going into deco, did not do the stops and it locked you out? Did you read the manual? Why not do the stops?

How far into deco was the Suunto? Would staying with in the NDL of it have made a significant difference? How much gas did you have?

Yes, I ignored the Suunto. I was aware that the Suunto was more conservative than my primary, so I ignored it. Yes, I did read and understand both the Suunto and Oceanic manuals. I was using a standard 80 cf tank. I don't remember how much air I surfaced with, but I never let my air get down to 500 lb. Looking at the tables included with the Zoop and VEO manuals at 60' first dive the Suunto gives you 50 minutes NDL and the DSAT Oceanic 57 minutes. That's a big difference! By the way, the Oceanic at 60' set in PZ+ mode gives you 48 minutes, and PSAT in conservative mode = 43 minutes NDL.

By the way, that was the last time I dove with the Suunto. I now dive with a Geo2 and a ProPlus3 backup. The Zoop was a nice package, but I found its lack of flexibility a real detriment, as I stated in my first post.

 

[scubadada]

@KenGordon and @dmaziuk

Why so defensive regarding your conservative deco algorithms? Let the educated diver decide.

 

[stuartv]

Forever. I dive with a lot of people with Suunto computers, some who have been diving for 30 or 40 years. They either do the stops or dive a sensible gas. They are using 15l cylinders for a first dive with 2700l usable, rather than 1700 with an Ali 80.

Unlike you, I have actually done liveaboards diving four times a day using Suunto computers and not had a problem. I have done a 3 dives a day southern Red Sea liveaboard (no night dives due to bitey beasties) with a buddy on a twinset and not got into more than a minute of deco at the end of an 80 minute dive.

You went from saying the guy won't be able to reach his NDL because he'll be gas limited to talking about going into deco.

And, I guess(??) you are now suggesting that if the OP does exceed his NDL, he should "do the stops", irrespective of whether he has any training for deco??

By the way, the question that I asked, which you quoted when you posted the above, was (paraphrasing to include the original context) "how many dives do you think the OP will do before he starts being limited by NDL rather than gas?" However, I'm not sure what question you thought you were answering.

So, which is it? Is he going to be gas-limited and doesn't need to worry about NDLs? Or is he going to be hitting his NDLs and should just not worry about exceeding them, because he should "do the stops"?

FYI, I was diving "best mix" Nitrox at dive 30-something when I started regularly hitting my NDL and then getting back on the boat with over 500 psi still left (often 900 or more). Diving a "sensible gas" doesn't magically give you an infinite NDL.

So, I ask again, how long do you think the OP will go before he stops being gas-limited and starts being limited by NDL? 20 dives? 30?

I 100% feel that getting training and learning how to do deco diving properly is the best, most freeing thing you can do to make your diving more enjoyable. At least, it was for me.

But, that training is expensive! Expensive for the tuition. Expensive for the equipment you have to buy (or rent). If all someone wants to so is enjoy single tank diving, and they want to maximize their bottom time while doing it, then telling them to "just do the stops" (with all the training time and expense that is actually implied in that statement) is just, well, I'll be nice and say "not very helpful."

 

[KenGordon]

You went from saying the guy won't be able to reach his NDL because he'll be gas limited to talking about going into deco.

And, I guess(??) you are now suggesting that if the OP does exceed his NDL, he should "do the stops", irrespective of whether he has any training for deco??

By the way, the question that I asked, which you quoted when you posted the above, was (paraphrasing to include the original context) "how many dives do you think the OP will do before he starts being limited by NDL rather than gas?" However, I'm not sure what question you thought you were answering.

So, which is it? Is he going to be gas-limited and doesn't need to worry about NDLs? Or is he going to be hitting his NDLs and should just not worry about exceeding them, because he should "do the stops"?

FYI, I was diving "best mix" Nitrox at dive 30-something when I started regularly hitting my NDL and then getting back on the boat with over 500 psi still left (often 900 or more). Diving a "sensible gas" doesn't magically give you an infinite NDL.

So, I ask again, how long do you think the OP will go before he stops being gas-limited and starts being limited by NDL? 20 dives? 30?

I 100% feel that getting training and learning how to do deco diving properly is the best, most freeing thing you can do to make your diving more enjoyable. At least, it was for me.

But, that training is expensive! Expensive for the tuition. Expensive for the equipment you have to buy (or rent). If all someone wants to so is enjoy single tank diving, and they want to maximize their bottom time while doing it, then telling them to "just do the stops" (with all the training time and expense that is actually implied in that statement) is just, well, I'll be nice and say "not very helpful."

Which part of “forever” and talking about people diving for 40 years did you not understand? Let me be clear. They will never need an aggressive computer.

I see that the concept of an example at the edge on endurance is too much for you. If an 80 minute dive is possible just hitting a minute of stops then a 75 minute one was possible without stops.

Actually all divers are trained to do stops. The question is about what the are called and what the computer will do if they are ignored. Scaring them to half to death over the odd minute is the unhelpful thing.

You also continue to chose to ignore the point that I have done these dives. My girlfriend is not keen on doing a load of deco (especially with Oceanic white tips as company) so on these sorts of liveaboards we don’t do that. she has a Vyper and I use a Helo2 to match it.

What you are advocating is chasing longer dives without adequate planning and resources. Use Nitrox, have long enough surface intervals and, if you really want plenty of time, do the stops. If doing the stops means doing more training then do that. 20 minutes on a 30m wreck isn’t plenty, a good reason to learn to use a twinset is to have longer safely.

I recently bought a DSAT computer so I can make these comparisons you lot all go on about. I had to buy it second hand as they are no longer available in the UK (except for one particular console based one tha5 was stupidly expensive). Aqualung don’t seem to have adopted it having taken over the former Oceanic range. Maybe it is not so golden?

Just for you, Stuart, have long enough surface intervals. Although I generally think teaching tables is a waste, the idea of an SI table which shows how tissue codes improve over time is useful.

 

[KenGordon]

@KenGordon and @dmaziuk

Why so defensive regarding your conservative deco algorithms? Let the educated diver decide.

There is no such thing as an educated diver regarding deco. Ask a deco scientist what constitutes aggressive or conservative deco and you will not get a hard and fast answer. There are many factors at play other than the profile. They will tell you having longer surface intervals and a sensible gas helps though. Take a look at the NEDU threads and the claims by Rossh about excessive deco, the profile still bent people.

Btw it is not ‘my algorithm’. I have the same number of ZHL16 dive computers as I have Suunto ones. I see (often having one of each on a dive) how they compare.

Why do I go after you and Stuart on this? Because you are telling new divers to behave badly and encouraging them to spend much more on a computer than they really need to. Their diving is likely to benefit more by spending the money almost any other way than on an expensive computer. More training, holidays, decent exposure protection, their own regs are all going to give more satisfaction.

 

[KenGordon]

I never let my air get down to 500 lb. Looking at the tables included with the Zoop and VEO manuals at 60' first dive the Suunto gives you 50 minutes NDL and the DSAT Oceanic 57 minutes. That's a big difference!

60ft is 18m so 2.8 bar ambient. Let’s choose 12l/minute as RMV as a reasonably good rate. That give 33.6l/minute at 60ft. So 50 minutes is 1680l. An Ali 80 starts with 2200l and has 1650l available (leaving 50bar for your buddy in case of emergency).

So, for this air consumption rate, there is no advantage to the DSAT, unless you start pushing your gas reserves.

Yes, there exist fit young people who will be better than 12l/minute in ideal conditions, but mostly they have to have buddies, they have to be back on the boat in a reasonable time, they get cold, they get bored and they run out of reef.

And yes, I know Scubadada is an unfit, old person who likes to boast of gas consumption which is less than I use sitting on my sofa watching boring telly.

 

[Magnus Lundstedt]

Suntoo RGBM is not the same in every Suntoo.

The Zoop is very limiting in repetitive dives, others like Cobra, Vyper, DX4 are different.

 

[Jay]

geeez it gets bad mannered a little too quickly

 

[KenGordon]

Suntoo RGBM is not the same in every Suntoo.

The Zoop is very limiting in repetitive dives, others like Cobra, Vyper, DX4 are different.

So, I own a Zoop, a Helo2, a Perdix and a Petrel (which is hardwired to a CCR). My girlfriend has a Vyper (which is almost the same as a Zoop but with a backlight). I have done a lot of dives with various combinations of these and with lots of buddies with DX, Eon and other Suunto. They come out quite close to each other. Typically the Zoop and Helo2 will be within one minute on a nonstop dive and similarly within a minute of stops for short deco. longer deco they will diverge slightly if you set the Helo2 to negative conservatism.

On the four dives/day holiday I am referring to above I used the Helo2 and the Zoop. These days I would uses the Perdix and the Helo2, but the profile would be the same.

The key thing to remember is that it doen’t matter what the computer says. What matters is how you dive. The computer might incentivise good behaviour but it isn’t stopping you getting bent.

 

[Oldbear]

Hi Ladies & Gents,

Appolgises for what I am sure is a very common topic.

I am recently qualifed OW and planning on eventually getting to wreck diving (long term goal).
Own already mask & fins and have been looking at dive computers in watch style.
Of course so many out there all with different features & price levels.

So far I've been focusing on the AL i200, Geo 2.0 & D4i Novo.

Are the Geo & D4i worth the investment or do you think at my current level I'd be better with the i200?
Hard to comapre when I don't have them all in front of me at same time.

Thoughts / comments / input based on personal experience greatly appreciated.

Cheers

Dan

Dan,

I am a dealer for all three dive computers.

For a newly certified diver who wants a watch style diver computer I would recommend NOT getting the Suunto. This computer is way to expensive for what you need. Buy one of the $389 computers and use the $400 towards a descent BALANCED regulator (which in my opinion should be your focus).

There is virtually NO difference between the Oceanic Geo 2 and the Aqua Lung i200. If you look at their Modes, software updates, functionality, etc. They are virtually the same. From a customer service perspective I have had excellent service from both now that Huish owns Oceanic. I am not sure but they might even be made at the same factory. Or Oceanic was made at the factory that now makes Aqua Lung...again not sure.

You might have read all of the scuttle butt about algorithms in earlier posts. Do not worry about these. All the dive computers will have a NDL of 54-56 minutes at 60 ft. You will not see the difference once you are diving as I hope that you start your ascent when you get to around 45 minutes to allow a safe margin.

You will be fine with either model and get YEARS of great diving with either. Sometime dealers have specials, you might look for those discounts at your local dive shop.

Go enjoy DIVING...

Michael