Oceanic Datamax Pro Plus Way Too Conservative

[cleung]

I have been using an Oceanic Datamax Pro Plus air integrated computer for years (my first one) but I have found that it is way too conservative. Whenever I do deep dives, it quickly gets into the deco red zone and starts beeping. This year, once in Roatan and once just last week in Baja, it actually locked me out during a dive where it would not give me time duration of my dive although it still had psi and depth. It wanted me to do something like a 10 minute safety stop in order to continue even though I had lots of air left.

All the other divers in the group had computers which indicated the dive was going fine. So based on my air, I continued to follow the group and at the safety stop, I physically had to count out the three minutes. During one of these lockouts, my computer did go back to normal mode but near the end of a safety stop while the other continued to lock out until the surface interval.

I could not find anyway to adjust this computer's profile and one of the instructor divemasters in Roatan told me the same thing happened to him when he started out with an Oceanic. Since he is a working diver, he had to switch to another computer that was less conservative. Most other divemaster instructors I've talked to also said the same thing that I should get a new computer that is at least adjustable with profiles. My dive shop at home recommended an air integrated computer by Suunto.

Has anyone else experienced this type of thing with Oceanic?

 

[fmerkel]

My dive shop at home recommended an air integrated computer by Suunto.

You got to be kidding!
One of the main endless themes on SB is about how wonderful vs. how conservative Suunto computers are. If your shop doesn't know this I'd consider all their input on the subject to be suspect.

OK.....here we go.....

 

[tursiops]

I have been using an Oceanic Datamax Pro Plus air integrated computer for years (my first one) but I have found that it is way too conservative. Whenever I do deep dives, it quickly gets into the deco red zone and starts beeping. This year, once in Roatan and once just last week in Baja, it actually locked me out during a dive where it would not give me time duration of my dive although it still had psi and depth. It wanted me to do something like a 10 minute safety stop in order to continue even though I had lots of air left.

All the other divers in the group had computers which indicated the dive was going fine. So based on my air, I continued to follow the group and at the safety stop, I physically had to count out the three minutes. During one of these lockouts, my computer did go back to normal mode but near the end of a safety stop while the other continued to lock out until the surface interval.

I could not find anyway to adjust this computer's profile and one of the instructor divemasters in Roatan told me the same thing happened to him when he started out with an Oceanic. Since he is a working diver, he had to switch to another computer that was less conservative. Most other divemaster instructors I've talked to also said the same thing that I should get a new computer that is at least adjustable with profiles. My dive shop at home recommended an air integrated computer by Suunto.

Has anyone else experienced this type of thing with Oceanic?

Three comments:
1. [sarcasm]Since you choose to ignore your computer, why do you carry one? Why don't you just continue to dive until your air runs out? What could possibly go wrong with that?[/sarcasm]
2. The Pro Plus is based on the PADI tables, which give less NDL (vs Navy tables) for the first dive, but enable shorter surface intervals and better NDLs for repetitive dives. Some old computers use the Navy tables, or similar. What were your dive buddies using that they got more NDL?
3. I'll guess your local dive shop sells Suunto, right?

Beware of trying to "adjust" a computer to obtain profiles that suit your diving. Better to adjust the diving to suit the computer's profiles.

 

[cleung]

I don't know what other divers are using. If this happened during just one or two dives, I would not make a deal out of this. But for several trips now over say 30-40 dives with different people, it is usually my computer that gets crazy first and I'm usually the only one with this Oceanic computer. I have lots of air left and do the same surface intervals as everyone else. So if I stick to what my computer says, I would be the only diver that goes up to do a 10 minute safety stop, again, even with lots of air left, while the rest of the group continues. So this is why I have concerns with my dive computer as these issues are not happening with anyone else in any of my dive groups.

 

[tursiops]

Ten-minute safety stop? Why?

Are you all diving air, or nitrox? What are the computers set for?

Does your computer display "DECO" when you overrun your NDL?

 

[fmerkel]

They are diving crazy dangerous. You are the safe one. Don't hang out with those people anymore, they are not good company. Only hang out with Suunto divers.

 

[gopbroek]

Until the Pro Plus 3 came out the Pro Plus used only the ZHL-16C (the Pelagic Z+) algorithim. The pro Plus 3 offered the dual algorithim of DSAT or ZHL-16C (the Pelagic Z+). The DSAT algorithim is the liberal algorithim that Oceanic is famous for, the ZHL-16C (the Pelagic Z+) is more conservitive. I run a VEO 3.0 on DSAT and a Pro Plus 2.1 (primarily for the easy digital pressure display) and often after a 4-5 days of diving the Pro Plus is bricked in violation mode. Intially the DSAT and ZHL-16C (the Pelagic Z+) run pretty close but after mutiple days of diving the ZHL-16C seems to become progressively more conservitive. Lately I have been trying to 'tune' the Pro Plus by adding 4-6 % O2 but it still is not as liberal as the DSAT. This kind of hightlights the problem attempting to match to different algorithims with tricks and I am waiting to see how attempts to match a computer with GF to other algorithims works out over a heavy dive schedule.

I originally tried a Suunto for drift diving in Cozumel with a 'dive your tank' operator. One trip and I went shopping for an Oceanic.

One thing for the OP, is it possible your altitude setting is not correct?

 

[tursiops]

Until the Pro Plus 3 came out the Pro Plus used only the ZHL-16C (the Pelagic Z+) algorithim. The pro Plus 3 offered the dual algorithim of DSAT or ZHL-16C (the Pelagic Z+). The DSAT algorithim is the liberal algorithim that Oceanic is famous for, the ZHL-16C (the Pelagic Z+) is more conservitive. I run a VEO 3.0 on DSAT and a Pro Plus 2.1 (primarily for the easy digital pressure display) and often after a 4-5 days of diving the Pro Plus is bricked in violation mode. Intially the DSAT and ZHL-16C (the Pelagic Z+) run pretty close but after mutiple days of diving the ZHL-16C seems to become progressively more conservitive. Lately I have been trying to 'tune' the Pro Plus by adding 4-6 % O2 but it still is not as liberal as the DSAT. This kind of hightlights the problem attempting to match to different algorithims with tricks and I am waiting to see how attempts to match a computer with GF to other algorithims works out over a heavy dive schedule.

I originally tried a Suunto for drift diving in Cozumel with a 'dive your tank' operator. One trip and I went shopping for an Oceanic.

One thing for the OP, is it possible your altitude setting is not correct?

No, this is backwards. The ProPlus ran DSAT only (the PADI tables), not ZHL. Quoting from the User Manual:
":NO DECOMPRESSION MODEL
Basis:
• Modified Haldanean Algorithm
• 12 tissue compartments
Data Base:
• Diving Science and Technology (DSAT) - Rogers/Powell"

 

[tursiops]

One thing for the OP, is it possible your altitude setting is not correct?

This is a good suggestion (I had a student with this problem once) but you cannot manually set the altitude on a ProPlus....it measures the Atm Pressure when it is turned on and uses that as its altitude. This means if you turn it on during an airplane ride to a dive trip, it thinks that is its starting altitude for any dives during the next 24h, until the tissue compartments all clear. This is all explained nicely in the User Manual.

 

[gopbroek]

No, this is backwards. The ProPlus ran DSAT only (the PADI tables), not ZHL. Quoting from the User Manual:
":NO DECOMPRESSION MODEL
Basis:
• Modified Haldanean Algorithm
• 12 tissue compartments
Data Base:
• Diving Science and Technology (DSAT) - Rogers/Powell"

I stand corrected and you are right. Now I am wondering if there are differences is the application of the DSAT algorithim between different Oceanic product lines. My PP 2.1 has always tracked progressively more liberal than a VEO ( one 2.0 and two 3.0's).