Surface interval

[Solly]

Hi, my question is related to mandatory surface interval time between repetitive dives. I am aware of the tables usage and group transition according to the surface time and these concepts but my question is related to what a DC shows as no dive time. How is it calculated and why? I mean it always appears regardless you plan a second dive or not (the DC doesn't know what is the depth you are targeting) so how come it shows a no dive surface interval.... anyone can explain this?

Thanks

 

[Damselfish]

what dive computer do you have, it's going to depend on the computer. All the computers I've had (Suuntos) don't show anything like that. You can go into dive planning mode and see the time allowed at various depths on your next dive were you to jump back in right then. But there is no "no dive" time. There is a "no fly" time, but that's another matter entirely.

 

[Solly]

thanks, yes I know the no fly.. I am talking about a suunto mosquito, there is this small triangle with ! inside that appears telling you to extend the surface interval ( as described by the manual) this is what confuses me, if you are doing safe dives and you know the plan for the next dive, it will be ok to just jump in the water knowing that if you extend the surface time you will be able to spend more time in the next dive.. but what about this surface time extension sign, why does it show and how is the time calculated...

Thanks for your help

 

[vladimir]

This is from the D9 manual. I'd expect the same to apply to your Mosquito:

Diver Attention Symbol--Advice to Extend Surface Interval.

Some patterns of diving cumulatively add a higher risk of DCI; for example, dives with short surface intervals, repetitive dives deeper than earlier ones, multiple ascents, and substantial multiday diving. When this is detected, in addition to adapting the decompression algorithm, the Suunto RGBM model will in some circumstances also advise, with the Diver Attention Symbol, that you extend your surface interval.

In other words, the computer does not agree that you are doing safe dives.

 

[Solly]

well this is a copy and paste from the mosquito manual
the dive profile when this occured was repetitive dive on a live board, but I guess it is just for precaution, all dive tables and other computers and even the mosquito itself after the dive and planning the next dive would give you reasonable time for the next time underwater.... I guess it is more like 'better not' but not 'you can't do it'
Anyway, to be more cautious is better than regretting the decision, afterall we search for fun

Thanks all for your input.

 

[dpaustex]

bounce diving will cause your computer to act more "conservatively", too. Don't know the sampling rate of the particular unit, but you'd be wise to further investigate. You can also e-mail Suunto.