Dive Computers and Deco

[DiveNav]

...... If all you're going to dive is Nitrox then the Trio or the other Seiko computers (Tusa IQ-950 Zen Air, ......) will work fine for you for a long time ...........

Actually the IQ-950 is NOT a Seiko based computer .... check page 7 of the manual

 

[DiveNav]

.....When faced with something like a new PCD, I'd rather know how it's going to function BEFORE I'm actually in the water. That's almost entirely what accounts for the success of something like DiveComputerNavigation.com, which btw I cannot praise enough! I just finished the OC1 course and quizzes, and seeing very gradual, step-by-step tutorials on how the computer will behave in the water before I get in the water is invaluable to me.

Hi,
I assume you meant DiveComputerTraining.com
I will take the compliment anyway and pass it along to the team.

Also, please note that in addition of seeing the dive computer in action in the class, you can actually take it for a spin (virtual) using the simulator and get it into deco as much as you want. BTW, in the sim we will not lock you out ... just start a new dive from fresh

Alberto (aka eDiver)

 

[Cleavitt]

At the risk of sounding like a smart ass, but you know that by reading the operator's manual. The manual will tell you when the computer will lock you out.

I don't think that his comment about knowing how the computer behaves was in reference to his previous question about deco violation. I think he was talking about being able to 'virtual dive' with his computer via DiveComputerTraining.com before ever getting in the water.

 

[zamburinha]

At the risk of sounding like a smart ass, but you know that by reading the operator's manual. The manual will tell you when the computer will lock you out.

It is not always that clear. The Suunto Stinger manual claims the computer will "look you out" for 24hours. That, however, does not mean that the device stops working altogether (as I interpreted initially), it means that it will no longer give you information on NDL time remaining and so on until you have stopped diving with it for 24hours.

I found that the Suuntos are extremely conservative. In one occasion I went slightly over the NDL, but the time the stinger wanted me to stay in the shallows was impractical in the circumstances, and was also a very very conservative value. I decided to cut short the shallows time and the computer was very unhappy. For the rest of the trip the suunto defaulted to a "gauge" mode which only indicated depth and time ... which suited me just fine

I am NOT advocating that you ignore your computer's advice. However, it is worth being a "thinking" user of a computer. A violation of the NDLs is not a binary event and you should know something about the model inside the computer and what assumptions it is making. For example, the suunto is programmed for the safety stop to last 3 minutes and to happen between 4 and 6 m (I think, if has been a while). If you follow a strategy of doing 1 minute stops every 3 m from half depth (as taught by some agencies), you end being forced by the computer model to perform an extra safety stop ... it won't hurt, but it is also somewhat overkill.

 

[fnfalman]

It is not always that clear. The Suunto Stinger manual claims the computer will "look you out" for 24hours. That, however, does not mean that the device stops working altogether (as I interpreted initially), it means that it will no longer give you information on NDL time remaining and so on until you have stopped diving with it for 24hours.

I found that the Suuntos are extremely conservative. In one occasion I went slightly over the NDL, but the time the stinger wanted me to stay in the shallows was impractical in the circumstances, and was also a very very conservative value. I decided to cut short the shallows time and the computer was very unhappy. For the rest of the trip the suunto defaulted to a "gauge" mode which only indicated depth and time ... which suited me just fine

I am NOT advocating that you ignore your computer's advice. However, it is worth being a "thinking" user of a computer. A violation of the NDLs is not a binary event and you should know something about the model inside the computer and what assumptions it is making. For example, the suunto is programmed for the safety stop to last 3 minutes and to happen between 4 and 6 m (I think, if has been a while). If you follow a strategy of doing 1 minute stops every 3 m from half depth (as taught by some agencies), you end being forced by the computer model to perform an extra safety stop ... it won't hurt, but it is also somewhat overkill.

I apologize. I don't have Suunto computers so I don't know how they are written.

My computers' manuals (Aeris & Sherwood) both stated at what specific conditions the computers will lock out for 24-hrs.

 

[Jax]

So, if you get out of the water and throw the computer on a string, how much time do you have to "re-descend" to the proper depth?

 

[Sephiro444]

I don't think that his comment about knowing how the computer behaves was in reference to his previous question about deco violation. I think he was talking about being able to 'virtual dive' with his computer via DiveComputerTraining.com before ever getting in the water.

Actually, it was a bit of both. The DiveComputerTraining.com stuff (sorry about that, Alberto! I always see your "DiveNav" username and had a mental hiccup) lets me see and try the computer the way it's supposed to be used, but just as I may never want to enter deco doing rec diving, I'd sure as heck want to know what's going to happen if I do. By the same token, if more extreme, I never want to violate the deco stop procedures, but if for whatever reason it happened, I'd want to know what I'm in for.

 

[fnfalman]

So, if you get out of the water and throw the computer on a string, how much time do you have to "re-descend" to the proper depth?

Great idea!!!

Strip the computer off and tie it to the mooring line/anchor line then surface and do your thing.