A Sincere Question about Console Vs. Wrist Computers
- Thread starter Scraps
- Start date
Please register or login
Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include
- Ability to post and comment on topics and discussions.
- A Free photo gallery to share your dive photos with the world.
- You can make this box go away
It would be interesting to find out what the old computers are doing. Im not sure but I think my shearwater uses 60 for > 60 and 30 for less than 60. At least for the rate indicator. I also want to say that there may have been a recent change to change the high rate alarm to be moved to 61 as opposed to 60 ft per minute. If that is the case then perhaps those rates are also used to calculate the expected total ascent / available off gassing time time that has to be used to calculate NDL
I think I would agree for MOST MODERN computers. I don't think my shearwater is like that though but then again it is not pure REC computer designed for the normal OW rec diver it is a tech computer with selectable modes designed with the thought that the user is given more control over things. . Example apure rec computers will lock up if you miss a stop. My shearwater will not. It expects the user to know how to remediate the condition with out a 24 hour shut down. Perhaps i should not refer to the age of the computer rather than the age of its programming and with what intentions and standards. Look how long it took PADI to come around to officially make the move to 30 ft / min. I would bet that there are lot of 80's puters out there that are not programmed with todays standards. The upside of those old programs that may be using 60 for calculations is that if you do 30 a minute you are ascending consevitivly in comparison to the expected rate of the computer.
Michael Jastrzebski
Contributor
If you look at the literature, air bubbles ascend at all kinds of speeds, greater an less than 60 ft.min....it depends on the size of the bubbles. the old "don't ascend faster than your bubbles" has been superceded by real data.
tarponchik
Contributor
I think you are correct, I remember in the early 2000's the idea of 30 fpm was getting momentum and perhaps PADI was one of the last to come onboard for their own reasons. That would suggest that any one with computers made in the 90's were probably not only updatable but their algorythms may probably be based on the faster ascents of 60 which was the excepted limit. Im not sure of when the no faster than your bubbles came out but I suspect it was a way to both transition from 60 to 30 fpm and a guide in the event of either a failed computer or diving with out a computer.
When it comes to computer data so much is tied to an assumed ascent rate .such as NDL TTS and more. I would probably have to run a dive plan to 100 ft for 2 minutes to see what the timing is on the ascent to determine the ascent rate being used. basically 100 ft in 3.3 minutes would be 30 fpm adn if 2 and 1/2 then it is using 60 when deeper than 60 ft and switching to 30 above 60 ft.
just looked at a petrel book and it has a indicator that is a 60 fpm range display. It also says that for deco calculations an assumed fixed rate of 33 fpm is used. I am going to assume that when they say deco they do not mean past ndl deco only, but that 33 fpm is used for all decompression calculations including pre ndl limit ascents. My aeris attmos 1 computers that had split rates of ascent on the ascent gage. Those puters were made pre 2000 era. i would have to ALSO look at the one prior tO that one and then the aTMOS ELITE AND THE ELITE t3
Similar threads
