How Accurate Should my Computer be?

[C6Diver]

I recently picked up a used Genesis Escort computer with a brand new battery. In trying it out in the pool during a refresher course it only reads 4-6 feet when I was at the bottom of a 10 foot pool. I could see how it could be off close to the surface but if the error continues to deviate as I go deeper it could be a problem. The H2O temp also not terribly accurate.

TIA

 

[barc802]

Make sure the pressure sensor is not blocked by anything.

I would want the computer to be dead on before I would use it on a real dive by itself.

 

[C6Diver]

Is this abnormal though? I'll look but I don't see how anything could be blocking the sensor.

 

[barc802]

Is this abnormal though?

I think so...

All the computers I have used in a pool are pretty close, with in a foot. We use a 10 foot pool for training and all the shops computers, mine and my citizen watch all say 10' max depth.

 

[Ann Marie]

Yes, it is abnormal! Depth measurement is extreamly important when diving.

I know that with the Suunto Computers that the tempature can be off a few degrees, but the depth should be accurate within a foot.

I personally wouldn't dive with anything when the depth is off more than a foot, especially when there is a larger margin of air the deeper you go.
Have you thought about trying to contact Genesis for their recommendation? If there is a problem with the computer, they can probably recommend a local facility that can make the needed repairs.

Welcome to Genesis Scuba!

By the way, welcome to ScubaBoard!

 

[C6Diver]

It's so old and I got it for so cheap that I don't think servicing it would be feasible. I'll contact the seller about exchanging/returning it and if I do dive with it I'll do lots of spot checks against the console depth gauge.

Thanks for the input.

 

[jaymal]

I know that with the Suunto Computers that the tempature can be off a few degrees, but the depth should be accurate within a foot.

So it's common the temperature for Suunto Computers to be inaccurate? My dive buddy and myself both have Cobra II computers and his read the temperature at 48 degrees while mine read it at 52 degrees. A 4 degree difference seems like a lot to me. I haven't noticed any inaccuracies in depth but am going to now have to check.

 

[DA Aquamaster]

One thought...if the computer is off and then auto activates in the water, you may get some error if it activates 4' deep at the bottom of your giant stride entry.

Especially in a high altitude diving situation, its a good idea to turn the computer on/ensure the computer is on just before you enter the water.

 

[Ann Marie]

So it's common the temperature for Suunto Computers to be inaccurate? My dive buddy and myself both have Cobra II computers and his read the temperature at 48 degrees while mine read it at 52 degrees. A 4 degree difference seems like a lot to me. I haven't noticed any inaccuracies in depth but am going to now have to check.

For the Cobra 2:

Temperature: Accuracy: ± 2°C/± 3.6°F within 20 minutes of temperature change

Depth: Accuracy: ± 1% of full scale or better from 0 to 80 m/262 ft at 20°C/68°F

Cold is cold, comfy is comfy, and warm is warm. When I'm cold, I for sure don't look at the temperature until I'm done diving for the day.

 

[JS1scuba]

Most Dive computers are NOT accurate in depths shallower than 10 feet especially in fresh water. They are even more inaccurate in inonized pools, because the water density is low.

Water temperature can usually take upwards of 15 minutes to get accurate IF you are going from a warm computer to colder water. This is not a hard and fast rule but one from experience.

Also ..... dive computers are calibrated so that they read a reasonably accurate depth. Some are calibrated for fresh water, others for salt water and some based on actual salinity/density (these are the most accurate).

To check the absolute accuracy of a dive computer it needs to be placed into a pressure pot and checked against another computer. Ideally it should be the same make / brand or at least from the same family of computers.

Other things that are to be considered is the altitude at which you test if not using a pressure pot.

Cheers