Pelagic computers, what's the real difference?

[handfulz28]

My first post here, lot's of good info and helpful people.
My girlfriend just got certified, and bought an Aeris Atmos AI to go with her Scubapro BC and regulator. Well since my gear is 13-14 years old, guess it's time to invest in something new.
So far all my research shows that the Aeris, Oceanic and Sherwood are made by Oceanic's Pelagic Pressure Systems. So besides price, are there any real feature differences that I should be aware of? I read one post which said the Sherwood doesn't show Remaining Bottom Time (i think) whereas the Aeris does.
I do like the whiz-bang of AI so I'm pretty convinced I want that. But you guys have me a little concerned about reliability so I'll want a backup pressure gauge at least. How do you get both an AI and backup out of one HP port? Are HP tees readily available?
Thanks,
Michael

 

[paulwlee]

I think most people diving with a backup SPG have regulators that have 2 HP ports.

Personally, I wouldn't worry about attaching a backup in your case since even if a tee is available (I've never seen one) it would be a bit messy. Although I do have a backup SPG, I've never needed it for the ~100 dives I did with my Vytec. If the transmitter dies mid dive for any reason, you can abort the dive just fine. It would be prudent, however, to carry around an SPG w/ hose in your save-a-dive kit, especially if you are going on a dive trip where lost dive opportunities due to malfunctions would be painful.

 

[miketsp]

All my regs have 2 HP ports. I thought that was normal.

 

[djac5700]

I have an Atmos AI and love it. Most people point out that the Pelagics use an older, more liberal algorithm as opposed to the Suunto's, which use a modern, conservative RGBM algorithm. This means that the Pelagics will usually tell you that you have more remaining bottom time for most recreational dives than a Suunto will. Personal preference and risk profile will dictate whether you want to be conservative or liberal.

Between the Pelagics, I went with the Aeris because I liked the full array of features and display. I found that the Sherwood and Aeris were very similar, but the layout and shape of the Aeris won out. I did not look at the Oceanic.

As for backup gauges, I do not currently have one, but I plan on picking one up to keep in a save-a-dive kit, as mentioned by paulwlee.

 

[paulwlee]

All my regs have 2 HP ports. I thought that was normal.

All the non-balanced pistons(e.g. SP MK2), the Aqualung Conshelf and derived designs (Titan), Apeks DS4's, etc. all have 1 HP port.

 

[handfulz28]

OK, so I'm not so worried about having the backup attached, but I'm still looking for more detail on the difference between the 3 brands.
Thanks,
Michael

 

[Kestrell]

OK, so I'm not so worried about having the backup attached, but I'm still looking for more detail on the difference between the 3 brands.
Thanks,
Michael

I think there is little to no difference other than appearance.

However, I did read an independant review that did show a difference in dive time remaining between two pelagics (Aeris and Oceanic). The Oceanic was even more liberal than the Aeris, so it may be possible that each company can specify its own unique programming from Pelagic.

I went with an Aeris Elite. Nice computer.

I also have a set of mini gauges clipped off to my BC. redundancy is good.

 

[Mark Vlahos]

OK, so I'm not so worried about having the backup attached, but I'm still looking for more detail on the difference between the 3 brands.
Thanks,
Michael

Hi,

I believe that the three brands (Oceanic, Aeris, Sherwood) are made by the same company, Pelagic Pressure Systems. I further believe that they all share the same algorythms. This is key. If they all share the same formulas for computing the time remaining on a dive, you are free to choose one over another for purely personal reasons. Do you like the layout of the display on one brand or model more than another? Does the warranty differ? Does your local dive shop carry one but not the other? Is the ability to purchase one on line but not another a deciding factor? Is the feature set on one particular model better for you?

What you should ask first, and perhaps you already have, is which set of algorythms do you like more. It is a generally accepted belief that older, or out of shape divers are more at risk of DCS. I do not know if you are older, out of shape, a smoker, like to dive while dehydrated, dive riskier profiles, or have any other reason to be more or less at risk of DCS than any other diver. Only you know how you stack up against the risks. Suunto RGBM computers and other computers that share the same basic set of formulas are percieved to be more conservative. The Pelagic Pressure Systems use different formulas and are percieved as either liberal or middle of the road (the depends on who you talk to) their bottom times do reflect a more liberal profile when compared to the RGBM models. I dive a Cochran computer which is extremely liberal at shallow depths, my personal choice with this computer is to set the user added conservatism fairly high. This results in bottom times more in line with the more conservative models from other manfacturers.

There are lots of brands and models out there so your choices are not easy. The computers made by Pelagic Pressure Systems are probably no more or less reliable than any other major brand of dive computer. In the past I have owned an Oceanic Data 100, and an Aeris 750GT. I did have minor problems with each of them but I found the computers to be generally reliable. The problems I did have with the Oceanic did not manifest itself in the water but were related to the PC download software and hardware. The Aeris would occasionally loose contact with the transmitter, but I was always able to re-establish the connection during the dive. I did also have some downloading problems with the Aeris. I have had only one minor problem with my Cochran which was quickly resolved before I got the computer in the water. I have not had any problems with my Cochran in the water.

I wish you luck in your quest,

Mark Vlahos

 

[djac5700]

As Kestrell mentioned, the only real difference in the computers is appearance. I like the Aeris over the Sherwood - but that's personal preference.

One other thing to consider is if you are thinking about buying online, Aeris and Sherwood allow authorized online retailers, but Oceanic does not. If you are looking to save money online, find a dealer who is authorized to sell them (I went with www.scubatoys.com, great experience).

 

[djac5700]

Regarding the algorithms, the following article will give you some comparisons (page 3 has some general info on DCS risk factors and page 4 has links to comparisons on actual bottom time remaining between computers) :

http://www.scubadiving.com/article/...X7X8X10X11X12X13X14X15X16X17X18X19-15,00.html