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Do it All Dive Watch/Computer?


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#1 mattsea

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Posted 13 November 2006 - 06:38 PM

Anyone recommend a dive watch/computer that has built in compass, ascent rate warning, depth, temp, deco stops (for different mixes), dive profile record, altitude AND is small enough to wear topside.

Remote sensor would be good.

If it had tides and sunset sunrise times that would be a bonus.

#2 ce4jesus

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Posted 13 November 2006 - 09:05 PM

Would you like it to make pancakes in the morning as well? haha. That's quite a list! The only one I know that even comes close is the Suunto D9 and that's a pricy piece of gear.
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#3 AndyBarker

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Posted 14 November 2006 - 02:15 PM

HI,

The only other one I know of is the Suunto D6 (BUT IT DOES NOT MAKE PANCAKES HAHA) :)

I don;t think it is quite as high spec as the D9 but it is £300.00 cheaper :)

Andy

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#4 John Bantin

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Posted 14 November 2006 - 02:25 PM

HI,

The only other one I know of is the Suunto D6 (BUT IT DOES NOT MAKE PANCAKES HAHA) :)

I don;t think it is quite as high spec as the D9 but it is £300.00 cheaper :)

Andy


If money is a problem you might like to wait for the Vyper2 (just announced).

I buy my own photographic kit. Diving equipment manufacturers and diving services suppliers get even-handed treatment from me whether they choose to advertise in the publications I write for or not. All the equipment I get on loan is returned as soon as it is finished with. Did you know you can now get Diver Mag as an iPad/Android app?

 

#5 mattsea

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Posted 14 November 2006 - 07:36 PM

HI,

The only other one I know of is the Suunto D6 (BUT IT DOES NOT MAKE PANCAKES HAHA) :guiness:

I don;t think it is quite as high spec as the D9 but it is £300.00 cheaper ;)

Andy

have looked at D6 and D9.

I liked the D9 specs but it is a bit heavy for every day topside use.
The D6 is smaller and light enough but does not have the remote tank sensor.


Both do not have altitude.


I had read something about Cressi EDY which has altitude but does not I think have
a remote read out from the tank like the D9.

#6 Rattus

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Posted 15 November 2006 - 05:58 AM

Just an observation, but surely if a computer is large enough to have all the info you want easily visible during a dive and have the UW receiver for tank pressure, then it's not going to be any smaller than the D9.

If you don't need the air (which I wouldn't do without now), you've got a choice of quite few nice computer/watches. The D6, the EDY and of course the Mares Nemo.

Myself, I like the huge readout on my Air Z Nitrox, but its a monster topside. My Nemo Ti should be arriving today if FedEx can be bothered. :guiness: That'll be by backup and what I wear between dives.

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#7 Glasseye Snapper

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Posted 15 November 2006 - 08:12 AM

I guess that in the "Unrequited Gear Lust" section anything goes, the more extreme the better.

But in my opinion your desires will force you to spend far more and still compromise on the individual functionallities you need. If I were you I would consider the new Oceanic VT3 which has all the dive computer functions you want in a very clear and readable package that can juggle 3 gas mixes with 3 transmitters (I just bought the older VT-Pro model that is now priced down to $550, has virtually the same functionality as the VT3 except it "only" handles a single gas up to 50% O2, good enough for me). You can look at the oceanic atom if you really insist your dive computer must look like a real watch.

Neither computer has a compass, but the VT3 can be attached to a retractor that you attach to your BCD. The computer sits on one side of the retractor and you can mount a bona fide high quality compas on the opposite side. Stick a $20 normal watch in your BCD pocket and put it on once you are back in the boat. You will have much better functionallity and save enough money to buy a nice lens, or a week of unlimite diving!

Bart

Edited by Glasseye Snapper, 15 November 2006 - 08:15 AM.

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#8 buddy

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Posted 15 November 2006 - 08:42 AM

the D9 got it all, including nitrox and other mixes and a digital compass. would not give it awyay anymore...

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#9 IMSushi

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Posted 15 November 2006 - 07:17 PM

As Bart said above, the Oceanic VT3 is great. Actually, I use the Atom 1, which is virtually the same but in a smaller package. It is about the size of my every day wrist watch, handles wirelessly up to 3 tanks of up to 100% O2, temp, time, projected NDL, etc. Sorry, no pancakes or compass. I just attach a real compass to a small retractor on my chest. The Atom 2 has just come out that addresses the issue of putting all urgent info on the main screen instead of scrolling back a page to find tank pressure. Oceanic's service is great too. I had a problem with my Atom 1 and an error code, sent it in, had a brand new one in my hands in 10 days.
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#10 Nazaar

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Posted 15 November 2006 - 10:12 PM

If I were you I would consider the new Oceanic VT3

Has Oceanic modified their deco model yet, or is it still in 'ultra-bendy mode'? The Oceanic's of about 2 years ago were well known for being ridiculously liberal with their NDL's compared to just about everyone else. Something else to considering when buying a computer...
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#11 Poliwog

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Posted 16 November 2006 - 06:34 AM

Has Oceanic modified their deco model yet, or is it still in 'ultra-bendy mode'? The Oceanic's of about 2 years ago were well known for being ridiculously liberal with their NDL's compared to just about everyone else. Something else to considering when buying a computer...


Just got the VT3 from Oceanic.

Have not had a chance to dive deep with it yet ( will do that next week in Curacao), but the VT3 allows you to set a conservative factor in the computer should you feel it necessary to take care of any "liberal ultra-bendy modes" you may feel you will encounter.

Had the Oceanic Proplus console mount computer, bought back in '98-'99, and had no complaints with it at all.

Also, I do believe it is not recommended, by anyone, that you dive to a computer or table NDL as the NDL is just a theoretical model or approximation and in no way represents real life.
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#12 Rattus

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Posted 16 November 2006 - 09:05 AM

the D9 got it all, including nitrox and other mixes and a digital compass. would not give it awyay anymore...


Hi buddy,

how do you find the clarity of the display underwater? My concern is that the numbers are a little small and the display is a little busy, but maybe in reality it's just fine. I'd like to hear your opinion on that.

Cheers,

Martyn
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#13 IMSushi

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Posted 16 November 2006 - 10:01 AM

Yes, Oceanic has changed their deco model, well at least they give you a choice now. You can put the computer into one of two models either the "ultra-bendy mode" or the more conservative mode. The default is the more liberal of the two. I forget which theory it is based off, Haldanean, etc.

Wait...I have my reference manual right here. Quote, "The decompression model used by an Oceanic dive computer is based on the no decomperssion multilevel repetitive dive schedules successfully tested by Dr. Ray Rogers and Dr. Michael Powell. These tests did not include repetitive dives deeper than 90 feet (27 meters) or decompression dives."

So, as I thought, this computer is not meant for the tech. diver routinely going beyond the 130 fsw magical recreational limit. But, in the computer's defense, as a recreational diver, if your first dive is to 130 fsw, your second repetitive dive should be made to 100 fsw or less.

As for the clarity of information given on the screen, just a glance is all I need. The numbers are large enough to see, and comprehend, without corrective lenses.
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#14 Glasseye Snapper

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Posted 16 November 2006 - 10:38 AM

The conservative versus liberal discussion for dive computers is probably never going to end. The VT3 and to my knowledge all other Oceanic dive computers (as well as a bunch of other brands) still use the Haldanean model with 12 tissue compartments. This is the most liberal kid on the block, with the Suunto computers typically being the most conservative.

We had a discussion a while ago where some people where complaining about the Suunto's conservatism and a few said they set the computer to nitrox, even though diving on air, to make it less conservative.

Agree with Mike, Sunnto are nice looking computers but crap on time, day after day the first up the line are the Sunnto users while the rest carry on diving, Sunnto have to be the most conservative computer on the market and for this reason I never recommend them to divers, Sunnto if your listening that's 100's per year in sales you miss out on. What's worse is I have a Sunnto D9 but have it set to 27% Nitrox which is still a little behind my Oceanic on air!

(quoted from Kriptap; for a lengthy discussion on dive computers and algorithms follow the "disccusion" link above).

I would far prefer a more liberal computer and add my own level of extra conservatism then doing it the other way around. Tons of computers using the Haldanean algorithm have been used on many many dives and I'm not aware of any reports by DAN or others that users with these computers get bend more frequently. Moreover, if the Haldanean was really high-risk, Oceanic and others would have long since stopped using it for fear of litigation.

I'm not saying that Haldanean is better than RGMB. It most likely is not as good a representation of reality. But at the end of the day the model may be less important than the database of dive data that is used to define the parameter values for the model.

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#15 Nazaar

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Posted 16 November 2006 - 06:17 PM

The decompression model used by an Oceanic dive computer is based on the no decomperssion multilevel repetitive dive schedules successfully tested by Dr. Ray Rogers and Dr. Michael Powell. These tests did not include repetitive dives deeper than 90 feet (27 meters) or decompression dives


See, to me that sounds pretty scary! So basically if I do a dive to 40m, no deco, and then one to 30m, the computer is basically untested??

But, in the computer's defense, as a recreational diver, if your first dive is to 130 fsw, your second repetitive dive should be made to 100 fsw or less.

The most recent studies have shown that the whole reverse profile thing being bad is bunk, and has no significant effect on your chances of DCI.

My concern is not that oceanic are liberal, but that people buy the computers not knowing facts like these. I agree that liberal computer that you can increase the conservatism on is better than a primarily conservative one, but most of the time the only that's going to prompt someone to go more conservative is if they or a friend gets a bend or a niggle, and by then it could be too late. If the computer isn't even tested for repetive dives beyond 27m, how conservative do you need to be?
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#16 Glasseye Snapper

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Posted 16 November 2006 - 09:32 PM

The most recent studies have shown that the whole reverse profile thing being bad is bunk, and has no significant effect on your chances of DCI.


In a May 2006 story in undercurrent, a study by McInnes, Edmonds, and Bennett (South Pacific Underwater Medical Society Journal 35(3): 139-143) was discussed where they subjected guinea pigs to forward and reverse dive profiles or forward and reverse repetitive dives. In the forward profile none of the guinea pigs developed DCS whereas in the reverse profile (with identical depths and times, just in reverse order) all 6 guinee pigs developed DCS symptoms and, in spite of oxygen treatment and recompression, all 6 died. For the forward repetitive dives, again none of the animal became sick whereas in reverse repetitive dives 4 animals died.

I did not read the original paper but the conclusion of the authors that reverse profiles carry significantly more risk seems convincing. It also makes lots of common sense. If you dive to 120ft stay 20 minutes and then come up doing whatever deco stops are necessary you should be save. If you do the reverse, start with the decostops and then spend 20 minutes at 120ft you will actually carry a larger N2 load when you start the ascent then in the forward profile. There is no way that you can go directly to the surface safely under these conditions. This is an extreme violation of the forward/reverse rule and the extend of the danger of minor reversals in profile may indeed have be exaggerated in common diving lore, but if there is no good reason to do otherwise, sticking with the forward profiles makes a lot of sense to me. Especially for those using the liberal Haldanean-based computers that don't penalize reverse profles. Bruce Wienke said that his RGBM algorithm in some Suunto, Mares and a few other brands do penalize for reverse profiles, so if you like to maximize your bottom time you should still try to stick with the forward profile.

In the earlier dive computer discussion there were a few list members with much more knowledge on the subject than I have. So please correct me if I'm wrong or if there are more recent studies.

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#17 Nazaar

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Posted 17 November 2006 - 01:06 AM

My understanding of it is that a lot of it depends on what you define as reverse profiles, and whether or not you can transfer the results from the guinea pig experiment to human research. A few quotes from Dr Simon Mitchell on the research methods:

The strict intent of the "historical" recommendation against reverse profile diving as I understand it was to prevent divers taking two dives (one deep followed by one shallow) and performing those identical dives in reverse order (shallow then deep) with absolutely no adjustment of the surface interval or the time / depth / ascent of the second dive in order to make it safer.


and

You can sum all this up by saying that divers want to do "reverse depth dives" with appropriate adjustment to the subsequent deeper dives to make them safe, NOT reverse profile dives in the strict sense. My main criticism of Carl's commentary is that nowhere does he try to make or clarify this distinction, and this was why the guinea pig experiment paper (see below) met with a somewhat hostile reception at the UHMS earlier this year.

I am much less inclined to argue strongly with Carl over whether or not true reverse profiles are a good or bad thing. Intuitively, I would avoid true reverse profiles (so we do have some common ground there), but not reverse depths where appropriate dive planning adjustments have been made to optimise the profile of the second deeper dive.


the guinea pig experiments were interesting but the results are very difficult to interpret in terms of human diving. In human terms, the profiles used would never be allowed by any human table or computer, and the dives were only 15 minutes apart (that is, they barely qualify to be considered as repetitive dives and are completely atypical of human repetitive dives). Carl insists that in guinea pig terms this all scales to realistic human dives, but for obvious reasons I seriously doubt that this can be considered well validated.


I apologise, I mispoke, I should have said that in 1999 the Smithsonian Institute held a workshop on RDPs which produced the following statement "we find no reason for the diving communities to prohibit RDPs within the the no-decompression limits for dives less than 40 metres and with depth differentials less than 12 metres". To my relatively limited knowledge, no studies using human data has refuted this, but frankly I'm happy to bow to anyone with more knowledge than I.

As far as I'm concerned whether or not a dive is a reverse profile or not pales into insignificance compared to an algorithm that doesn't even acknowledge that repetitive dives past 27m are performed by recreational divers! To simply say 'oh, well that's alright because we never do reverse profiles anyway' is a little short sighted I would have thought?
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#18 Glasseye Snapper

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Posted 17 November 2006 - 09:10 AM

Hi Nazaar,

I completely agree with your last message and the quotes of Dr. Mitchell. For me the guinea pig experiments prove that forward and reverse profiles/repeat dives are not identical. This seemed completely obvious to me anyway and thus a questionable use of animal studies. Of course you can do reverse profiles and repeat dives with appropriate dive planning adjustments. Some (all?) of the RGBM algorithms apparently already do this. The problem is that for historical reasons there is much more data on dives following forward profiles so I'm not sure if the RGBM model had enough data to determine good parameters for the model. If not, perhaps they decided to play it safe leading to an overly conservative computer.

The same data problem leads to the limitation of the Haldanean model. It used data from what was considered typical and representative recreational dive profiles (I believe PADI commissioned the formation of that data set for their dive tables). The dive tables and Haldanean model are thus only "proven" to work well when you stay within that type of dive profiles. The VT-Pro manual explicitly states that Tech divers and divers that want to make dives outside these boundaries should not use the computer.

So everyone can argue that the Oceanic computers are not acceptable because they want to dive outside those limits. But for those that plan to stay within those limits anyway they are completely fine. Almost anything to do with safe diving is about staying within your limits of skills, training and equipment. I don't think this is any different.

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#19 Poliwog

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Posted 17 November 2006 - 09:24 AM

Thanks Bart!

Couldn't have said it any better! :guiness:
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#20 Nazaar

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Posted 17 November 2006 - 03:30 PM

The dive tables and Haldanean model are thus only "proven" to work well when you stay within that type of dive profiles. The VT-Pro manual explicitly states that Tech divers and divers that want to make dives outside these boundaries should not use the computer.

Huh, I see what you mean. Maybe they're the only ones being honest, or maybe it's just them being conservative. A little ironic, no?
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