Ascent Rate - Deep Dives

[Azza]

I read the open water book from cover to cover 4 times already and watched the DVD 3 times and on my fourth time (I want to be as prepared as possible before I start my class in three weeks). There is no mention of 30fpm anwhere. If you look at the definitions in the back it states on page 239. "ASCENT RATE - the proper speed for ascending, which is no faster than 18m/60 feet per minute. A rate slower is acceptable, and appropriate." It does say that an slower ascent rate is appropriate, I was just trying to see where the 30fpm comes from because none of PADI's materials mention a "30fpm" ascent rate.

Hmm. Sorry to put you wrong on that. I have been trained through the PADI system and was told all the time that 30 fpm is the recommended and 60 fpm is the maximum. This is also something I pass on to my students.
To be honest I never bothered checking my manual. I will do tonight when I get home.

 

[ScubaSarus]

I dont see a problem wuth 30 ft/min provided you don't blow your NDL time. That may be hard to do on a very deep dive near the NDL.

 

[rockjock3]

Hmm. Sorry to put you wrong on that. I have been trained through the PADI system and was told all the time that 30 fpm is the recommended and 60 fpm is the maximum. This is also something I pass on to my students.
To be honest I never bothered checking my manual. I will do tonight when I get home.

Cool. My instructor might do the very same thing you do with your students. I will also always use a very slow, but safe, ascent rate. I just wanted to try and find out where the 30fpm was coming from since everything that PADI has says 60fpm and nowhere is the 30fpm mentioned (at least for the OW crew pack).

Thanks again for the info.

 

[vjongene]

Yup, but still one should stress not going too slow. Because TBT is based on when you ascend, this assumes a certain rate of ascent. Going up at 5feet/minute breaks the assumption of the table, and may cause problems. But that said, if you aren't pushing the tables, this really shouldn't matter too much.

CMAS procedures are that if you ascend at less than 10 m/min (30 ft/min), then you should add to your bottom time the extra time that you take to reach your first deco stop, be it mandatory of safety only. Makes sense to me.

 

[Charlie99]

I generally do a 1 minute at each of 30 ft, 20 ft, and 10 ft.

i do the exact same thing. i was taught this in dir, got into a lot of trouble doing these when the other folks were doing 3 mins at 20ft.

http://www.scubaboard.com/showthread.php?p=844330 is a discussion that might help clarify what GUE is teaching, and how poorly a slow linear ascent performs in doppler studies by DAN Europe.

Charlie Allen