Should I consider Nitrox?

[Cortex_prime]

Hello. I am applying to conduct a research project involving scuba diving in the Cayman Islands. My maximum depth is no more than 20 feet (in Stingray City). I plan to make three dives a day over the course of 14 days. I will remain underwater for 30 minutes. Would diving nitrox as opposed to air potentially have any benefit at this shallow of a depth? More specifically, could it increase my bottom time and the number of dives I can make in a day?

 

[shurite7]

Most likely not. When ever we took tourists to Stingray City we used air in the tanks.

 

[tbone1004]

max of 20ft gives an unlimited bottom time so you could stay down on surface support for the full 14 days on air and literally never surface, then immediately get on a plane and have no issues. Nitrox would be a waste for that

 

[EastEndDiver]

What research project are you involved in?

 

[shurite7]

tbone, you have a point. Most people, however, don't have the air consumption to make it worth the while. Plus one will have to have the cert to use any mix above 40%.

 

[tbone1004]

tbone, you have a point. Most people, however, don't have the air consumption to make it worth the while. Plus one will have to have the cert to use any mix above 40%.

huh? What does air consumption have to do with any mix over 40%?
If you dive with mixes over that, you're going to be limited by the CNS clock before you get limited by NDL's regardless of your SAC rate.

The "best mix" for 20ft, is basically O2, so there's no point in diving that.

With an extremely high sac rate of 0.7 for working, you still get about 70 minutes at 20ft with an al80, that's more than enough time to do most things on a working dive before you get cold and hungry and need a break. You can do as many of those dives a day on air as you want and never have to worry about NDL. Hell, I probably wouldn't bother taking a computer in the water unless you wanted to log the dives

 

[shurite7]

huh? Even with a bad SAC rate, an al80 will last for about 70 minutes at 20ft. That's long enough.

Best to just dive air for anything up to 40ft because nitrox won't do anything for you

I would be happy to dive 50 or 80% if someone else was paying for it.

 

[tbone1004]

I would be happy to dive 50 or 80% if someone else was paying for it.

why? what does it get you? 50% makes your EAD 1ft. EAN80 makes it 19ft above the surface.... 50% literally is like not diving, 80% is going to have you offgassing the whole dive, and while neither are a bad thing obviously, they both have serious complications to logistics of filling, requiring O2 clean regulators, CNS clock, etc without increasing the safety of the dive

 

[Lake Hickory Scuba]

I just produced a series of videos on our YouTube channel,www.youtube.com/user/lakehickoryscuba, in regards to Nitrox and the myths, misconceptions, and benefits of using it. Hopefully this will be helpful to you.

 

[shurite7]

why? what does it get you? 50% makes your EAD 1ft. EAN80 makes it 19ft above the surface.... 50% literally is like not diving, 80% is going to have you offgassing the whole dive, and while neither are a bad thing obviously, they both have serious complications to logistics of filling, requiring O2 clean regulators, CNS clock, etc without increasing the safety of the dive

Reality it gets me nothing, but if some else is paying and supplying the equipment, I might just take it. As you stated, the CNS build up is a significant issue, and the normal recreational mix of 32% or 36% really don't offer much benefit either. Personally I would chose air.