Nitrox for Liveaboard - Great Barrier Reef

[tursiops]

If diving Nitrox does not give you more bottom time, do not dive Nitrox.

When does diving Nitrox to recreational depths not give you more bottom time, assuming you have sufficient gas supplies?

 

[lowwall]

When does diving Nitrox to recreational depths not give you more bottom time, assuming you have sufficient gas supplies?

Well, dives less than 20-30 feet (depending on your algorithm of choice). So Blue Heron Bridge.

 

[tursiops]

Well, dives less than 20-30 feet (depending on your algorithm of choice). So Blue Heron Bridge.

Yes, you might find an algorithm that allows that. I cannot.
USN table (and their variants such SSI) do not allow that...Nitrox gives more time. Multideco using 70/85 to 25 ft saltwater requires deco on air after 654 minutes bottom time; Nitrox32 gives more bottom time, although at 757 minutes you reach 100% CNS.

 

[tarponchik]

Yes, you might find an algorithm that allows that. I cannot.
USN table (and their variants such SSI) do not allow that...Nitrox gives more time. Multideco using 70/85 to 25 ft saltwater requires deco on air after 654 minutes bottom time; Nitrox32 gives more bottom time, although at 757 minutes you reach 100% CNS.

At BHB you'll run out of air well before N2 saturation, and because of the tides and park hours, you can only dive once a day. Dania erojacks diving is pretty much the same, though less tide dependable. Manta Ray night dives in Kona are also shallow, so why bother.

Another case when Nitrox is useless is on group boat dives when everyone follows the same profile and has the same bottom time. Some operators allow for extra 5 min for Nitrox divers but most do not. Some sucker runs out of air in 30 min and hasta la vista, baby, your dive is over.

 

[lowwall]

Yes, you might find an algorithm that allows that. I cannot.
USN table (and their variants such SSI) do not allow that...Nitrox gives more time. Multideco using 70/85 to 25 ft saltwater requires deco on air after 654 minutes bottom time; Nitrox32 gives more bottom time, although at 757 minutes you reach 100% CNS.

Your SAC must be incredible

 

[scubadada]

...Another case when Nitrox is useless is on group boat dives when everyone follows the same profile and has the same bottom time. Some operators allow for extra 5 min for Nitrox divers but most do not. Some sucker runs out of air in 30 min and hasta la vista, baby, your dive is over.

Why would you ever dive with an operator like that?

 

[tursiops]

Your SAC must be incredible

I wish! Luckily, the issue was whether Nitrox gives more bottom time, not whether the dive is doable. I think it does: the N2 ongassed is always less with Nitrox.

 

[Tracy]

Another case when Nitrox is useless is on group boat dives when everyone follows the same profile and has the same bottom time. Some operators allow for extra 5 min for Nitrox divers but most do not. Some sucker runs out of air in 30 min and hasta la vista, baby, your dive is over.

What boats operate that way and why would you ever go back to an operator that runs it that way?

 

[tarponchik]

What boats operate that way and why would you ever go back to an operator that runs it that way?

That was Rocket Frog in Costa Rica.

 

[tarponchik]

Why would you ever dive with an operator like that?

Quite often you do not know in advance. Also, this may depend on the DM you have. For example, on LVB in Maldives our DM stricktly enforced group rule while another DM did not seem to care if one or two of his divers strayed away or asked for extra time.