Shearwater Petrel Questions

[declan long]

So Today i finally got wet with my new divve computer. But some quick questions:......

1) it diddn't turn itself on, should it?
2) i also had my suunto gekko with me (shearwater set on salt water) and on the 1st dive the shearwater was showing .7m shallower than the gekko but on the second dive only .3m shallower, why please?
3) temp was slightly off?
4) dive log was weird, said i started dive at 10.31 and ended at 11.16 but said a 47min dive? explain please?
5) it was showing less ndl than my gekko, yes because of rgbm but showed no safety stop and only 3min tts from 30m?


cheers declan long.!!!!!!

 

[tstormdiver]

1. Usually you have to get several feet down for it to come on automatically. I just turn mine on before getting in the water.
2.Any computers can be a ft or 2 off from another. I also understand that Shearwater's computers use temp as part of the depth (could be wrong on that, but seems I've heard it somewhere).
3. Temps can also vary from computer to computer.
4. If the computer did not turn on or get turned on, until that depth, it won't read the depths until that time.
5. Shearwater computers do not do safety stops. It is up to the diver to count the time of a safety stop, themselves. 3 mi. to the surface from 60 ft would be about right, as the algorithm slows you down, the shallower you are in your ascent.

 

[Dr. Lecter]

If you will not/cannot read the manual, you should probably not be diving a SW.

 

[Dive-aholic]

The Shearwater computer turn on about 2 minutes after being submersed. Easier to just turn it on yourself before the dive.

It's not uncommon for depths and temperature to be slightly off. It's a matter of calibration. It's usually not that big of a deal.

My Predator and Petrel also show the minute "discrepancy". It counts the minutes and seconds and rounds up. Sometimes it's right on the mark. Sometimes it's a minute more than the time. Also, if you spend any amount of time shallower than a meter or so at the beginning or end of the dive then your descent and ascent times are going to reflect that.

Shearwaters don't make you do a safety stop. That's on your training. Most deco computers assume you know enough to do a safety stop when needed. Ascent is calculated at 10m per minute so 3 minutes from 30m is correct.

 

[waterpirate]

I have founf that a diver using two different computers, from two different manufacturers will never be happy! Read and understand the manual. Leave one of the computers in gauge mode and carry tables.
Eric
YMMV

 

[shoredivr]

I did an educational chamber ride to 200 ft, and took a bucket of water and 6 different brands of computers in the bucket. At depth one showed 197 while another showed 206. Only one said 200ft. All were set for fresh water.