New Computers Reducing Bottom Time

[jerzeedivr]

I don't like that most new computers are Reducing Bottom Time from 80' 40 Min. from Navy Decompression Charts to 80' 26 Min. I under stand the Safety Limits. But who wants their Computer Stealing 14 Minutes or 1/3 of your time? NOT ME!

 

[tursiops]

If you are happy to use a dive table (Navy that shows 40 mins) that was replaced by the Navy some years ago, then go for it.
"I under stand the Safety Limits" I don't think so.

 

[northernone]

If you don't want increased safety margins feel free to not use them.

If we're in the physical condition, have the training and the surface support that the navy does, feel free to use their tables while accepting the risk factor involved.

Dive and let dive.
Cameron

 

[scubadada]

I don't like that most new computers are Reducing Bottom Time from 80' 40 Min. from Navy Decompression Charts to 80' 26 Min. I under stand the Safety Limits. But who wants their Computer Stealing 14 Minutes or 1/3 of your time? NOT ME!

USN 2016 gives 39 minutes. "Modern" computers vary depending on their deco algorithm. For example, Cochran 33 minutes, DSAT 30 minutes, PZ+ the 26 minutes you quote. Of course these are 1st dives and square profiles.

 

[MaxBottomtime]

I have a Scubapro Galileo Luna set at a ppo of 1.6, which gives me 40 minutes at 80 feet on air.

 

[tursiops]

I have a Scubapro Galileo Luna set at a ppo of 1.6, which gives me 40 minutes at 80 feet on air.

Why does the PPO2 matter for this?

 

[MaxBottomtime]

Sorry. I set it to 1.4 and still have 40 minutes.

 

[boulderjohn]

Most people are doing multiple dive days, and you need to look at the second dive, too. People started moving away from the Navy tables because of the long surface intervals required after those longer first dives. Your computer algorithm may be giving you a longer second dive sooner than you would have with the Navy tables.

 

[tursiops]

Sorry. I set it to 1.4 and still have 40 minutes.

I'm not surprised! Unless you set it to 0.72 or lower, your computer (on air) won't care what it is, it will still give you the same NDL at 80 ft,. After all, the only thing the PPO2 setting is doing is telling you how deep you can go before you hit your oxygen toxicity limit. For PPO2=1.4, that is 187 ft. For PPO2 = 1.6 that is 218 ft.

PPO2 is about oxygen and oxygen limits.
Setting the FO2 to 21% (air) is about nitrogen and NDL limits.
Different things.

 

[scubadada]

I have a Scubapro Galileo Luna... ...which gives me 40 minutes at 80 feet on air.

I don't think there is any way that Scubapro's Buhlmann ZH-L8 ADT MB will give you 40 minutes at 80 feet on air, check again. This is a middle of the road to conservative algorithm.