OLED Wrist vs OLED Console Dive Computers...

[Lucifer911]

Hi @Lucifer911

It has always been very interesting to me that divers looking to buy their 1st computer, or to upgrade, rarely mention the decompression algorithm as an important variable. I am convinced that this topic is not covered in scuba training and is often avoided by those selling computers. Choosing an inappropriate decompression algorithm is one cause for buyer regret, perhaps one of the most common.

Are you aware that the 6 computers you listed run 6 different decompression algorithms covering nearly the entire spectrum from conservative to liberal (Suunto RGBM, Mares RGBM, PZ+, Scubapro Buhlmann ZH-l16 ADT MB, Atomic RGBM, and DSAT)?

You might want to educate yourself on this topic so that you can use it to make the best, informed choice for your 1st dive computer.

Best of luck in your purchase and good diving,

Craig

as I'm still inexperienced I thought the deco algorithms will be based on the numbers listed in the US Navy diving table. It would be nice if all watches followed the standards and guidelines set in the RDP Dive Table. Thanks for bringing this issue up as it will definitely help me eliminate computers I would regret buying.

 

[scubadada]

as I'm still inexperienced I thought the deco algorithms will be based on the numbers listed in the US Navy diving table. It would be nice if all watches followed the standards and guidelines set in the RDP Dive Table. Thanks for bringing this issue up as it will definitely help me eliminate computers I would regret buying.

The US Navy tables are very aggressive and were not designed for repetitive recreational diving

The PADI RDP is only one set of tables designed for repetitive recreational diving. They have been available since 1987 and were developed in conjunction with the DSAT computer algorithm. From Deco for Divers, Mark Powell, 2014:

The M-values used for the RDP were adopted from the Doppler bubble testing and tested by Dr Merrill Spencer and tested by Dr Raymond E Rogers, Dr Michael R Powell, and the colleagues with Diving Science and Technology Corp, a corporate affiliate of PADI. The DSAT M-values were empirically verified with extensive hyperbaric chamber and in water diver testing and Doppler monitoring.

 

[Jonny Wishbone]

Hers something to think on as well. If you buy a computer that is non serviceable, meaning the type that are encapsulated in a polymer resin on the inside, and something goes wrong with it, you will be forced to buy a whole new computer unless it is under warranty. This is usually from a manufacturer that only cares about the income it can generate and cares nothing about its name. Those encapsulated modules are trash, junk, garbage, rubbish, what ever word describes a piece of $hit in your area. Make sure you but one that can be repaired and/or serviced. Also get reviews on the manufacturer's customer service and how they handle things and take care of their customers.

 

[Lucifer911]

The US Navy tables are very aggressive and were not designed for repetitive recreational diving

The PADI RDP is only one set of tables designed for repetitive recreational diving. They have been available since 1987 and were developed in conjunction with the DSAT computer algorithm. From Deco for Divers, Mark Powell, 2014:

The M-values used for the RDP were adopted from the Doppler bubble testing and tested by Dr Merrill Spencer and tested by Dr Raymond E Rogers, Dr Michael R Powell, and the colleagues with Diving Science and Technology Corp, a corporate affiliate of PADI. The DSAT M-values were empirically verified with extensive hyperbaric chamber and in water diver testing and Doppler monitoring.

I think one of the reasons why the dive shop owner never mentioned differences of algorithms in computers was because I'm only an open water diver predominantly a jetty diver. He mentioned I am more likely to run out of oxygen before I ever hit the no deco limit even with a conservative algorithm. I was thinking under what conditions can an OW rec diver with a limit of 18m hit the NDL? maybe if I was on a dive boat with at least 4 tanks I might come close if my surface intervals are really short. On the jetty dives it would still take me at least 20minutes minimum to walk back to my car and replace air tank with fresh tank then arrive back to my dive spot. My dive spot is around 8-10m with a deep channel of 20m but there's not much to see in the deep channel.

Perhaps I could progress to AOWD in the future and relocate to Queensland with dive locations much deeper than 20m and would therefore desire a computer with a more liberal algorithm. In South Australia the waters can go deeper than 30m but this is a long way from the shore and often in treacherous waters which most boats avoid cruising to.

I really think the Shearwater Perdix AI is the best now that I think about it for several reasons...

1) I can easily find scuba buddies with this system so if I get in trouble they will know how to fix my computer
2) warranty.. because its so popular in Australia it would be easier to get it replaced or fixed
3) because of its trimix function, if I ever needed to sell, it would be theoretically easier to sell because of its popularity and desired by the tech diver demographic
4) option to access this DSAT algorithm (right now not a huge incentive but might be in future)

 

[scubadada]

Hi @Lucifer911

The Buhlmann ZH-L16C with gradient factors on the Perdix AI has 3 present GFs in the rec mode, ranging from very conservative to quite liberal. In the tec mode, it is nearly infinitely adjustable.

There is no reason to have access to DSAT if you are already diving Buhlmann, it is simply a different option, as are all the other decompression algorithms

 

[outofofficebrb]

I will address the wrist vs. console subject for you. When I started diving, I bought a wrist unit for a few reasons. I briefly considered console, but did not want an in-line hose option such as the Oceanic Pro Plus X or the Suunto Cobra because I did not want to rely on an electronic item (where battery levels or possible malfunction can be an issue) for my air pressure. I decided if I were to do a console, it would be a basic computer on the console with an analog SPG on it. The console seemed less interesting to me as time went by because I did not want to have to drag my whole reg set with me to review dives and dive logs. Also, when traveling, I would want to hand carry my dive computer. So, with that in mind, you would need a quick disconnect hose to achieve this or to unscrew the dive computer from the console. The latter is a hassle and as for the QD hose, circle back to my battery and malfunction concerns with the SPG. I suppose you could still have a backup analog SPG.

I know people that have in-line consoles either as a primary or a backup and also dive a wrist based one as a primary or backup that also has wireless air integration.

After taking the rescue course, it became very clear to me that there is a benefit on having my dive computer on my right wrist as it has been. In some rescue scenarios, your left hand is occupied managing your inflator hose and your right hand is busy holding the reg in the victim's mouth or handling other gear. It was nice to be able to see my depth and ascent rate on my wrist as I was holding my victim's reg in their mouth. I hope that this will never happen in real life but it is a possibility. Lastly, if I need to switch out my reg due to a malfunction or issue, I can easily just take the wrist mount with me and not worry about switching gear over and splash for my next dive right away. It's very portable.

Much later (now), I have picked up underwater photography and it is much more convenient to have the data at my wrist where I am holding my camera. It's easy at-a-glance information rather than pulling out a console even if it is hooked onto a retractor on my shoulder d-ring. I don't have to take my hands off my camera rig. I just look down.

 

[Gareth J]

Dive computers are split into two primary groups, Sports Diving, and Technical Diving.

The largest volume are the Sports diving market, Suunto, Uwatec , Aqualung etc,). These have a locked in algorithm, which will generally be quite conservative. Generally they have functions like Nitrox. These will serve the vast majority well for many years.
These are pretty safe, you can argue about how conservative an algorithm is, but out of the box they are good to go.

The Technical computers are more likely to run pure technical algorithm, i.e Bhulmann, etc.
How conservative or aggressive the computer is up to the operator, this generally means adjusting gradient factors. If you run them too aggressively, the risk of a bend is quite high. (i.e100/100).

With regard to console or wrist, I would go for wrist. Its generally far more convenient, than console. It's much easier to glance at the computer when its on your wrist, rather than locating a console and moving it into your eye line. Where you have in water controls, like gas switching, display mode switching (e.g. compass), wrist mounting is far easier.

Dive computer watches suffer from display size issues. I see these more as a fashion statement than a good in water option. The big push to OLED has significantly improved readability, especially for 'old' eyes, or those who are wearing glasses.
I know Suunto go in for a lot of stick here. I have had a number of Suunto's over the years.
My first was the originally EON, which was a console air integrated unit.
I got rid of this in favour of a wrist mounted Vyper. I also had a Vytec (excellent). I killed one Vytec death sensor, and flooded another. The Vyper is still going strong and must be one of the originals.
I never found the algorithm overaly conservative.

My recommendation is one from a big dive computer manufacture, Suunto,Uwatec etc. rather than a smaller manufacturer or a rebadged one.
The Tech range are great, but expensive, and you do need to understand about setting them up with reasonably conservative setting, most people never progress to this level of requirement. In two to three years there may well be better tech' computers available.
I have avoided air integrated ever since my first. Its an expensive addition, another failure point. A normal gauge is inexpensive and reliable.

Gareth

 

[scubadada]

@Gareth J

"Sports Diving" computers are not necessarily conservative and recreational divers do not necessarily want to dive conservative computers. Your sweeping generalizations are inaccurate.

 

[Tribal]

I live near cold waters (13c during winter and a max around 21c during summer) most of the year the temperature is below 20c. Why would temperature of water influence decision on what computer to use? unless it generates a nice amount of heat lol

Small buttons don’t work that well with drygloves and thick undergloves, or 5/7mm wetgloves.

Ps 13c sounds like summer

 

[Gareth J]

@Gareth J

"Sports Diving" computers are not necessarily conservative and recreational divers do not necessarily want to dive conservative computers. Your sweeping generalizations are inaccurate.

I don't really agree with you here. The earlier computers of the 80's where far more aggressive than the modern computers. All of the modern 'sports' diving computers have modified algorithms, none run vanilla Bhulmanns or RGBM, or US Navy tables (or other algorithms). They all have addition padding and modifications.
This is easily demonstrated by comparing them with the standard Bhulmann table, or even just comparing them with something like a Perdix set to 100/100.

Whilst you might argue that 'sports divers' don't want a conservative model. I know of very few OW divers who understand decompression models, and gradient factors. Most new divers are limited far more by the gas they carry than the decompression model in their computer. In fact there are very few sports diver training organisations that teach decompression diving from the get go, probably with the exceptions of SSA and BSAC. PADI certainly don't. I think DIR might now, I believe they have modified their training to include an OW entry qualification.

I don't run 100/100 on my CCR or on my main computer. The back up computer is set to 100/100. Following the backup is for when the **** really hits the fan, it will get me out of the water as fast as is possible. Once on the surface I can go onto 100% O2 and consider evacuation.
Even the modern 'tech' computers are nothing like the original VR3.

Gareth