Nitrox vs larger tank

[Peter Guy]

Amongst other things, the OP wrote:

When we dive air, nitrogen is almost always the limiting factor for me whereas it seems that air remaining is always the limiting factor for him irregardless of the FiO2.

This really struck me for IF they are diving as a buddy team, why would one have N2 loading issues while the other has gas limitation issues? Shouldn't the N2 loading be the same for both buddies? OP -- can you explain how you get N2 loaded while your buddy doesn't?

Also, my belief is always "More gas is better.". IF both have the option for 100s, why not both dive them? What's the downside of someone have "more gas than they need?". And while I'm aware "some" frown upon the practice, IF the "sipper" has way too much gas, the "Hoover" can always "borrow a cup of air" from the sipper.

 

[scubastingray]

This really struck me for IF they are diving as a buddy team, why would one have N2 loading issues while the other has gas limitation issues? Shouldn't the N2 loading be the same for both buddies? OP -- can you explain how you get N2 loaded while your buddy doesn't?

What OP is saying here, is that if he were diving alone he would hit the NDL, except he dives with a buddy. This buddy runs out of air long before OP can hit the NDL. If OP were a solo diver nitrox would benefit him, except he's not so he's wondering if a larger volume of air for his buddy would be a better or if he should get nitrox. Obviously with 80CF he can't even hit the NDL for air, so nitrox will be of no benefit when he is buddy limited.

 

[T.C.]

This really struck me for IF they are diving as a buddy team, why would one have N2 loading issues while the other has gas limitation issues? Shouldn't the N2 loading be the same for both buddies? OP -- can you explain how you get N2 loaded while your buddy doesn't?

Different computers, different profiles. One buddy is probably about 5-7 feet deeper than the other.

And while I'm aware "some" frown upon the practice, IF the "sipper" has way too much gas, the "Hoover" can always "borrow a cup of air" from the sipper.

Is that really Doing It Right?
What will the rest of the anointed ones say?

 

[chillyinCanada]

Candiru, have either you or your buddy taken Nitrox training? Also tell your buddy to quit using his arm/hands. soon as he quits flapping around under the water, his SAC will improve a bit right away.

 

[Candiru]

Yes, we always get to his reserve before we hit NDL, same computers. that's the point I was trying to get across to him. I'm sure that the 100s would be better than 80s on nitrox. The suggestion that both dive 100s is a solid one.

Thanks for all the suggestions, trip starts tonight, we'll see if logic wins.

 

[Kharon]

Not going to read the entire thread but - Nitrox for you and 100cf for him. Any other combo won't increase BT. You are running out of nodeco therefore Nitrox. He is running out of air therefore more air.

 

[scubastingray]

Different computers, different profiles. One buddy is probably about 5-7 feet deeper than the other.

No, it's the same profile. Buddy 1 is a sipper, and would be able to hit NDL except that he has to surface when buddy 2 runs out of air (leaving them easily within NDL). Read the thread. They have the same nitrogen loading as they are doing the same dive.

 

[T.C.]

No, it's the same profile. Buddy 1 is a sipper, and would be able to hit NDL except that he has to surface when buddy 2 runs out of air (leaving them easily within NDL). Read the thread. They have the same nitrogen loading as they are doing the same dive.

Where does he state this? I gave a reasonable scenario where this could happen. Nothing he said contra-indicates this.

You're taking other diver's words as his. Since he runs out of NDL time first, clearly they do NOT have the same nitrogen loading. Since they have the same computer, that means one diver is most likely at a deeper average depth during the dive.

 

[Centrals]

To the OP,
Get the bigger tank(air) for both of you in the beginning. And if your buddy can last the pace then get him to use nitrox subsequently. On the other hand, both of you start with large nitrox tank and see what happen at the end.

 

[scubastingray]

Where does he state this? I gave a reasonable scenario where this could happen. Nothing he said contra-indicates this.

You're taking other diver's words as his. Since he runs out of NDL time first, clearly they do NOT have the same nitrogen loading. Since they have the same computer, that means one diver is most likely at a deeper average depth during the dive.

Dude, reading the thread helps...

Yes, we always get to his reserve before we hit NDL, same computers. that's the point I was trying to get across to him. I'm sure that the 100s would be better than 80s on nitrox. The suggestion that both dive 100s is a solid one.

Thanks for all the suggestions, trip starts tonight, we'll see if logic wins.