Suunto No Fly Time

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gasgirl

Contributor
Messages
154
Reaction score
42
Location
Vancouver, BC
# of dives
200 - 499
I just checked the Suunto owner's manual and it states the No Fly Time is based on the Residual Nitrogen calculations. I averaged 3 dives each day usually around 60 minutes bottom time on EANx 32%. There were no mandatory decompression dives. My computer gave me a No Fly Time of around 24 hrs after my last dive. Does this sound right? It seems ultra-conservative given that my dives seemed to conform to the 18 hr guideline by DAN.
 
You said "each day" so I assume you did multiple dives over multiple days.
I would agree with the computer and wait 24hrs unless the last days' dives were all very shallow (below 10m).

The 18hr figure is a minimum value, not a recommended value.

Remember, the DAN studies were based on dry, resting divers. When I travel, it's often tiring, stressfull and very physical, heaving suitcases & dive equipment around. Security checks, connections etc.
 
I would also agree with 24 hours no-fly time recommendation for multi-day diving. That's something you'll usualy get as advice.
 
Thanks for the feedback.

Just thought it was curious since I was diving EANx 32% all week and the Suunto was more conservative than the 18 hr DAN guidelines which are presumably for multiple dives on air.

My average depth for my all my dives were fairly shallow (35 to 45 ft)... that's the beauty of Bonaire's reefs.
 
I've got a Favor. On my last trip did two dives a day during the last two days, on air, and had a no fly time both days of aver 18 hours. Suunto computers seem to be on the conservative side from my experience and everyone I've talked to that owns one.
 
Much better safe than sorry, I would agree with no fly recommendation for multiple dives a day. I have myself a Suunto and I was surprised few times by their recommendations... but again better safe than sorry.

Robert
 
StingRob:
Much better safe than sorry, I would agree with no fly recommendation for multiple dives a day. I have myself a Suunto and I was surprised few times by their recommendations... but again better safe than sorry.

Robert

I have no problem with being conservative... I guess that's why I bought a Suunto. It's just that DAN is not exactly reckless so just wondering why the big discrepancy? Does anyone know how Suunto actually derives their No Fly Time? All the owner's manual says is it is calculated from the Residual Nitrogen.
 
gasgirl:
I have no problem with being conservative... I guess that's why I bought a Suunto. It's just that DAN is not exactly reckless so just wondering why the big discrepancy? Does anyone know how Suunto actually derives their No Fly Time? All the owner's manual says is it is calculated from the Residual Nitrogen.

I have been told (may be just an urban legend) that DAN wanted to increase the No Fly Time recommendations on pure technical grounds but came under commercial pressure not to do so. A 24-48hr recommendation would hardly affect the accident statistics but it would have a significant impact on dive operations ( & profitability) in tourist areas. So it is understandable that any increase would be hard to justify.

As for the calculation method in the RGBM algorithm, I've worked through some of Bruce Wienke's papers and the math is not for the faint of heart. :wink:

Also don't forget that your Suunto does not just work on depth alone. If you abused your profile, fast ascent, short SIT etc, this is taken into account and will penalise you.
 
gasgirl:
I just checked the Suunto owner's manual and it states the No Fly Time is based on the Residual Nitrogen calculations. I averaged 3 dives each day usually around 60 minutes bottom time on EANx 32%. There were no mandatory decompression dives. My computer gave me a No Fly Time of around 24 hrs after my last dive. Does this sound right? It seems ultra-conservative given that my dives seemed to conform to the 18 hr guideline by DAN.

I just came back for a trip to cozumel yesterday. And we had a pretty intensive diving schedule (17 dives in 6 days). My computer (Nitek Duo) gave me a total desat time (no fly time) of 28 hours which I thought was pretty conservative. However my flight was within 25 hours of my last dive so I got on the plane. While in the air I was looking at the computer and the nitrogen load went way up for most of the flight since cabin pressure is around 7500 ft. I would be careful about flying with less than 24 hours since even we only 3 hours of desat time before takeoff. I ended up with 29 hours in the plane and within 1 bar of the red zone. When we landed I had been bumped to 5 hours of desat time.
 

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