Suunto Mosquito Question

[Seuss]

I bought a Suunto Mosquito dive computer a last week. On my fifth dive with the computer, I noticed something odd.

The first dive that morning was to 71 fsw max, 45 fsw average, for 44 minutes. A normal three minute safety stop was made and no ascent speed violations were made. I still had around 30 minutes left for a no-decompression dive when I surfaced.

The second dive was after a 43 minute surface interval. I was down for 54 minutes with a max depth of 31 fsw and an average depth of 22 fsw. Again, no ascent speed violations were made. I was nowhere near a decompression limit, but upon ascent, the dive computer went into manditory decompression mode!? This lasted for about two seconds, and then went into the normal three minute safty stop mode.

When I look at the dive log, it has an attention symbol. Watching the dive profile, the attention symbol occurs right as I break 20 fsw on ascent towards the safety stop at 15 fsw (ascending at a rate less than 33 ft per minute).

I put two more dives on the computer since this happened, being careful to stick to a table dive plan and not to trust the computer, just in case. Both of the dives went fine and the computer did not switch into decompression mode for either dive (which was the correct behavior).

What should I do? Is there something wrong with the computer, or is it safe to trust it again? I went back to the LDS where I purchased the computer, but the yoyo (he is a DMC) behind the counter seemed to think it was user error. (I have a BS in Computer Science and minor in EE. I have done my fair share of ASIC and PCB design. I have read the manual several times and know for fact that this was not user error!)

Has anybody else seen anything like this? What would you do in my place? Thanks for any feedback!

 

[Bob3]

You might want to watch your hand movement, if you move your arms around a whole lot while ascending you can sometimes fake the critters out.
I'd say keep an eye on the thing & dive it, keeping your tables handy.

 

[Seuss]

> if you move your arms around a whole lot while ascending you can sometimes fake the critters out.

Hmmm... I hadn't thought of that, but I am pretty sure it wasn't an issue in this case. I was actually watching the computer when it switching into and out of the mode, which means it was stationary with respect to my body as I was ascending.

 

[GUEdiver]

Seuss, I know a number of folks who use the Mosquito or Stinger, and on occasion, they experience similar "bumps" in what the computer is showing/recommending in terms of deco / safety stops. In our experience, it is usually just a function of the fact that Suunto's algorithms are extremely conservative. Just keep using it and watching it closely (as it seems you were/are based on your detailed description). If it continues to wander into deco mode, contact Suunto for assistance and/or replacement. I've always found them to be very rapid and considerate in responding to a customer service issue. Good luck and happy diving. PS - you probably already carry a backup depth & timing device, just in case the Mosquito locks up.

 

[Lightning Fish]

Seuss:

I have a Vyper and the same thing happened to me. As I started to ascend I moved my hand up at the same time and faked it out. The computer said I was ascending too fast and went into deco mode for about 2 seconds. This was the second dive of the day and on both dives I was about 7 minutes from the NDL limits at max depth. (88 fsw and 68 fsw). I would have to review the manual but I think if you ascend too fast under certain conditions the computer may go into deco mode, even if only briefly. And I think the Suunto's will punish your subsequent dives if you have a surface interval that is less than an hour.

Hope this helps.

Cheers,
Bill.

 

[rcohn]

Realize that the Mosquito uses a 20 second sample interval time. Quick motions, up a few feet, then down again may not be seen in the recorded dive profile but they can trigger an ascent rate warning.

I doubt you were in mandatory decompression, but rather a mandatory safety stop for a few seconds. This occurs if you violate the ascent rate by a margin you will be able to look up in the manual.

Ralph

 

[IslandHopper]

My Stinger has done the same thing a few times ... I have yet to figure out exactly what causes it ... All the information given by the computer is still accurate (at least in my cases).

Always have an idea of what your dive is like in relation to tables ... then as long as your computer is in the ballpark, I figure it's trustworthy.

P.S. ...as far as I know, this has only occurred on my Stinger when set to EAN at 21%. (but it could be that those are the only times I've noticed it.)

 

[pismodiver]

That was (technically)not a deco obligation, but a mandatory safety stop, secondary to a momentary rapid ascent rate. (Likely from moving your wrist up to eye level as other posters have posited.) It's in the manual on page 35.

 

[hrandolph]

I am interested in buying the Suunto Mosquito Dive Computer. Should I purchase this one , or would you recommend another ?

 

[El Orans]

I'm still a happy Mosquito user.