Is nitrox worth it for deeper rec dives?

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Depends on the dive. . . . I went to North Carolina to do some wreck diving on some old wrecks from world war II and you want all the bottom time you can get since some of the wrecks are in the 100-130ft range. We brought 28% steel 100hps for that exact reason, specifically when we dove the German sub that sank there. This sub lives right at the 110ft mark or so if memory serves me correct and time flies when you are trying to check the entire wreck out at those depths so yes, an extra 3 minutes was definitely worth it for that dive. I do recommend 100cu tanks for those dives because they are exciting and you can suck air down pretty fast when taking pictures and such.

I'm not usually one to do everything possible to squeeze an extra minute of bottom time, but I have to agree with you on that one. The boat ride out of Morehead City is almost three hours to reach the U-352. All so you can have your few precious minutes on that wreck.
 
On a square profile, you just have to figure if the two minutes are worth the money for Nitrox. With a multilevel dive it's much easier to justify.

For me it is the other way around, on multi-level profiles it is harder to justify nitrox. While for fairly square profiles nitrox provides me the most benefit.
 
For me it is the other way around, on multi-level profiles it is harder to justify nitrox. While for fairly square profiles nitrox provides me the most benefit.

I'll bet your dives are not trying to maximize the time at 130' as the OP is, ymmv.


Bob
 
I'll bet your dives are not trying to maximize the time at 130' as the OP is, ymmv.

Depends on the wreck, but sometimes I am pushing 130' and wanting to maximize my time. Now when possible I will stay up on the super structure to increase my dive time, as when bouncing those 10-15 minutes at 130ft I am almost always returning to the boat with a nearly full tank.
 
On a square profile, you just have to figure if the two minutes are worth the money for Nitrox.
Huh? Rule of thumb: in the deeper part of the rec depth range, your NDL on 32% is some 50% longer than on air. Last time I checked, the PADI RDP said that the NDL for a square profile to 40m/130' is 9min, and for 30m/100' it's 20min. 50% of that looks a bit more than two minutes to me.

Besides, if you stay roughly within air NDLs due to being gas limited, you're quite a bit away from maximum N2 loading. Which translates to shorter SIs and possibly less post-dive lethargy (at least for those of us who believe so).
 
A couple of days spent doing AN/DP/Helitrox would render most of this discussion moot. It isn't rocket surgery, after all. As someone above said, more tools in the toolbox. I've done enough dives up here in similar conditions to know that if I was still interested in doing them I'd be using a light mix whenever I could, so I could remember more of what I saw when back on the boat.


Rocket Surgery? Ha! I am going to steal and abuse that misnomer to no end hahaha
 
Huh? Rule of thumb: in the deeper part of the rec depth range, your NDL on 32% is some 50% longer than on air. Last time I checked, the PADI RDP said that the NDL for a square profile to 40m/130' is 9min, and for 30m/100' it's 20min. 50% of that looks a bit more than two minutes to me.

Although we would use 32, the OP only uses 28. And I mis-remembered the 2 minutes, I looked and she said she gained 3. If it was a shore dive, the advantage of nitrox could be used on the slope, with a square profile to the boat you have to balance the 3 minute gain with the cost of the nitrox mix, and possible O2 cleaning.



bob
 
Although we would use 32, the OP only uses 28. And I mis-remembered the 2 minutes, I looked and she said she gained 3. If it was a shore dive, the advantage of nitrox could be used on the slope, with a square profile to the boat you have to balance the 3 minute gain with the cost of the nitrox mix, and possible O2 cleaning.
Ok, I missed that the OP was using 28%. Then the advantage of course is less than with 32%, but in any case the N2 loading will be smaller. Which in my book still is better than riding the NDL.

But that's me. Again, others' MMV.
 
Think of it this way: of all the expenses you rack up for the opportunity to get a couple of dives in, why would you try to save $20 bucks by buying air instead of enriched gas? More bottom time or an added level of safety, both are worth the extra bucks.
 
https://www.shearwater.com/products/perdix-ai/

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