What's the difference between a dive computer and a bottom timer?

[H2Andy]

depends on who you ask

i was trained on 1.4 for the working part of the dive and 1.6 for deco

[Cave Bum]

but what about FRESH WATER????

Change 33 to 34, of course!

((1.6/1.00)-1)*34=20.4 Ft

[Cave Bum]

1.6 is the recommended maximum PPO₂. It is my understanding that not too long ago, it was not uncommon to dive to 2.0 PPO₂.

I have only been diving for 18 months, so if there are any divers out there with more information in this regard, I'd be happy to hear about it.

Thanks in advance

Best Regards
Richard

Not that I've ever heard. The NOAA standard was always 1.6 PO2 max even back to NOAA manuals I have published in the 70's. The technical agencies have been teaching for years 1.4 PO2 for the working portion of the dive and 1.6 PO2 for the deco portion.

However, in the last couple of years we've had several fatalities where divers were within that recommended 1.4 PO2 range. One issue seems to be divers who are very athletic, who are in really great shape, tend to process oxygen more efficiently, leading to OxTox at or below the 1.4 PO2 threshold.

Because of this, many divers in the technical community have been pulling back a little from the maximums.

[Jim Lapenta]

ANd as a result of these incidents the shop I now dive with mixes for 1.3-1.35 for the dive. Still using 1.6 for deco but I see nothing wrong with lowering that as well. I use v planner and hace my settings at 1.3 and 1.5 for deco. Although I am not by any means an olympic class athlete!

For the OP I use a veo250 for recreational stuff and set it to gauge with an OMS bottom timer as backup for technical.