Diffrent deph on computers?

[LindaN]

Hi!
I recently had a experience with quite some diffrences in what deph me and my buddys computer showed on the saftystop, a diffrence of about 2,5 meters. I have a suunto mosquito (reasently changed batteries) and she a viper 2.

Is that kind of diffrences between brands normal (we were almost sholder to sholder when looking)? Have to say that even if my computer normaly agrees with others about deph I checked my against another computer later on (yes, we had same deph) but that was also a suunto. I like to belive my computer but since her things is checked (she's anew diver and have a bit protecting techdiving boyfriend and divestore owner) I do wonder :confused:

Well, no real harm in that situation this time since we did a shallow short dive..

[Richard Whitcombe]

Different brands will sometimes read different depth due to fresh vs salt calibration etc.. The same brand/design as in your case should be similar give or take 30cm or so.

We did a dry dive a while ago in a chamber and tested our computers. At 40m all the suuntos read to within 20cm, an aladdin was 1.5m deeper than actual.

Im not sure i'd be happy with a 2.5m variation at any depth range.

[Michael Purcell]

My Suunto D9 and my wife's Mares Nemo are out by up to 2 metres.
I've never really looked into it as when I noticed it was at a time when she stopped diving for a while.

I did do a bit of reading about it and someone suggested the suunto gets "confused" when you do a rapid descent before it switches into dive mode. (IE: you are at 3 metres before it gets to dive mode) This didn't really ring true but as I don't really know how it calibrates itself I can't really comment.

Would be nice to know as right now my black box of death is set to pretty conservative settings but in Mexico this summer we will be adjusting the computers to be less conservative.

[LindaN]

Different brands will sometimes read different depth due to fresh vs salt calibration etc.. The same brand/design as in your case should be similar give or take 30cm or so.

We did a dry dive a while ago in a chamber and tested our computers. At 40m all the suuntos read to within 20cm, an aladdin was 1.5m deeper than actual.

Im not sure i'd be happy with a 2.5m variation at any depth range.

I didn't like it either, especially since she was a great buddy with whom I love to dive some more since we both enjoyed each others company and then I don't wanna risk either of us.

This time where we well within limits of direct acsent and compromised the stop to 4,3 meter and a shorter stop at 3 m acording to my computer. Well, if something like that should shove itself was it good that it came on such a shallow dive, first dive of the year, so we did a "babydive" to get rid of som rust :)

If it hade been a deeper dive would we probarly had 2 stops to make sure.

[Steve in Sharm]

Hi!
I recently had a experience with quite some diffrences in what deph me and my buddys computer showed on the saftystop, a diffrence of about 2,5 meters. I have a suunto mosquito (reasently changed batteries) and she a viper 2.

Is that kind of diffrences between brands normal (we were almost sholder to sholder when looking)? Have to say that even if my computer normaly agrees with others about deph I checked my against another computer later on (yes, we had same deph) but that was also a suunto. I like to belive my computer but since her things is checked (she's anew diver and have a bit protecting techdiving boyfriend and divestore owner) I do wonder :confused:

Well, no real harm in that situation this time since we did a shallow short dive..

2.5 metres difference on a safety stop......

Thats well wrong. You should take both computers to your LDS and get them pressure tested at the same time - and if its yours that is out (as I suspect), hand the bill over to whoever changed your batteries...... :cool:

Until then just go by the most conservative computer then no-one will get hurt.....

[Richard Whitcombe]

Out of interest what did your analogue depth gauge read or didn't either of you carry one?

[LindaN]

2.5 metres difference on a safety stop......

Thats well wrong. You should take both computers to your LDS and get them pressure tested at the same time - and if its yours that is out (as I suspect), hand the bill over to whoever changed your batteries...... :cool:

Until then just go by the most conservative computer then no-one will get hurt.....

My feeling exactly.. Since this is the first time since the battery change and this problem didn't shove on the dives after the change and shoved the same as another computer on the following dive (also shallow and well within limits of direct ascent) do I suspect that its mine thats corect but will check it to be sure since this summer probarly will have some, for me, deeper dives and I wanna be sure.

Well, until thats fixed I think that I borrow my boyfriends bottomtimer for backup :D

[Michael Purcell]

Out of interest what did your analogue depth gauge read or didn't either of you carry one?

Good to see regular members can be

http://www.globalconsole.net/troll.jpg


(j/k):p

[Richard Whitcombe]

Good to see regular members can be

(j/k):p

Joke aside im of the view that a depth gauge is vital and you dont want to carry just one set of vital equipment. A backup gauge, no batteries or flood issues just in case the computer goes insane.


Back to topic though, you can sort of test, get a long bit of rope, attach both computers to the bottom of it, possibly with a shot weight. lower it off the side and recover it. Note the max depth of both to see if they agree. If they dont, if you knew the length of the rope (assume no current) or the exact depth (echo sounder or a 3rd computer) you can compare both to real and go from there.

[LindaN]

Out of interest what did your analogue depth gauge read or didn't either of you carry one?

None of us was smart enough to carry one, didnt feel like we really would need one since our planned max deph was 16 meter and we made sure to check the table before just in case. Well, next time my boyfriends bottomtimer will join the computer..

[LindaN]

Joke aside im of the view that a depth gauge is vital and you dont want to carry just one set of vital equipment. A backup gauge, no batteries or flood issues just in case the computer goes insane.


Back to topic though, you can sort of test, get a long bit of rope, attach both computers to the bottom of it, possibly with a shot weight. lower it off the side and recover it. Note the max depth of both to see if they agree. If they dont, if you knew the length of the rope (assume no current) or the exact depth (echo sounder or a 3rd computer) you can compare both to real and go from there.

Thanks for the tip! Sounds like an idea and I know just a good spot for that.