Multiple dives, multiple days..Nitrox

[tangfish]

totally sold, I love the freedom of shore diving, have no problem lugging tanks around to be able to do whatever, whenever and for however long. what about linking up with buddies there? If I went there solo, would it be pretty easy to find some other divers to buddy up at my accommodation? is there a particular resort you think would be best for this purpose? I've heard a lot about buddy dive.

 

[jepuskar]

That I'm not too sure about. You could try Bonairetalk or this board to look for people who are going to be down there then. There are always people shore diving and you will notice people loading up their vehicles at the dive resort...you could always approach people that way. You could also go out on a boat trip and meet people and invite them to go shore diving with you.

My only problem with that is you never know who you're getting in the water with. I did a night dive with a guy from New York..didnt know him....that had to be the most nerve racking dive of my life. We descend and he took off on me...I ended up with another buddy by the end of the dive.

 

[alemaozinho]

Hi,

My buddy and I are thinking of using Nitrox for 7 straight days of atleast 4 dives a day. We both have Nitrox compatible computers, but have never dove over multiple days with Nitrox.

We are going to Bonaire, so we probably could get away with using 36% the whole trip, but would be pushing the 24 hour exposure limits..according to the tables anyway.

Any deep dives like the Hooker would probably be done on air or 32%.

Has anyone dove this much exclusively on Nitrox for multiple days and used a computer? If so, what % did you use and were you even close to reaching your exposure limits?

We have multiple options on how to use Nitrox, like using 36% for our last few shallower dives of the day..etc.

Any insight would be appreciated.

Thanks,

Jason

makesure to watch your oxigen exposure and i would take a day off in between to offgas(not farting)

 

[alemaozinho]

sorry i meant to watch your OXYGEN (bloody typeboard)exposure and i would take a day off in between to offgas(not farting)

 

[mer]

The one thing I don't understand about Nitrox is that it significantly lengthens your no deco stop time, however, it doesn't reduce your chances of DCS by that much, using even an air profile...this confuses me.

How can they say its ok to dive x amount of minutes more, which in some cases is quite alot, and then say, ohh yeah, you pretty much still have the same chance of DCS even if you do dive an air profile......can someone explain that to me?

Jason

If you are using an Nitrox computer (in Nitrox mode for that mix) or appropriate Nitrox tables, you have the same DCS risk as an air dive; however, you have more NDL time.

Why? DCS risk is related to nitrogen loading. The NDLs are established for the highest "tolerated" nitrogen saturations levels. When that level is reached, your NDL is used up and your computer will kick into deco.

The main thing that matters for AIR vs. EAN dives is the amount of nitrogen in what you breath. Since you breath less nitrogen when on nitrox, your RATE of on gassing is slower than when breathing AIR (given same depth dive). So on nitrox, it takes you longer to reach that highest "tolerated" nitrogen saturation... thus a longer NDL. Since you have the same amount of nitrogen as after a shorter air dive, your DCS risk is theoretically the same.

Now if you want a larger safety margin, dive nitrox (well above it's MOD mind you) but use air tables. In this scenario, a nitrox diver will have a lesser nitrogen load than an air diver on dives of equal length and depth. Less nitrogen, smaller risk.

In short, you get added saftey margin (reduced DCS risk) OR greater time at depth. Pick one.

 

[mer]

Hi,

My buddy and I are thinking of using Nitrox for 7 straight days of atleast 4 dives a day. We both have Nitrox compatible computers, but have never dove over multiple days with Nitrox.

We are going to Bonaire, so we probably could get away with using 36% the whole trip, but would be pushing the 24 hour exposure limits..according to the tables anyway.

Any deep dives like the Hooker would probably be done on air or 32%.

Has anyone dove this much exclusively on Nitrox for multiple days and used a computer? If so, what % did you use and were you even close to reaching your exposure limits?

We have multiple options on how to use Nitrox, like using 36% for our last few shallower dives of the day..etc.

Any insight would be appreciated.

Thanks,

Jason

To echo what others have said, it might be hard to get something other than 32% (31-33) on Bonaire. Nitrox packages are rather cheap on Bonaire, so just dive 32% for every dive, and keep yourself above 110' (or better 100').

From what I have read, many recreational agencies are recommending taking a day off from diving every 3-4 diving days. YMMV, but I would seriously suggest taking days off, and go stuff yourself with crepes.

If you do dive straight through, understand that you are exposing yourself to a higher risk of DCS (even if on nitrox). Multi-multi day diving is in it's infancy of research. Do you like being a guinea pig.

Keep in mind that the hyperbaric docs on Bonaire don't speak English all that well... but the sight of a DAN preferred insurance card makes their eyes light up.

 

[jepuskar]

Mer,

I appreciate your comments about taking days off and we are planning on doing that. We arrive on Saturday at 3:30pm, so from then until the next morning we wont dive. We leave the following Sunday the 22nd around 4:30pm, so roughly between that time and 4:30pm on the 21st, we wont be diving either. Ofcourse we will have to sleep sometime in these 8 days also, so that is the extent of non-diving activity.

One thing I think i worthwhile doing for us would be to take a break in diving Nitrox about halfway through the trip for a solid 24 hours.

Also, using Nitrox and diving air tables doesn't really give us any significant increase in safety. We each have Nitrox computers and will be watching those very closely and allowing significant time for our safety stops.

 

[Scubaguy62]

As long as you monitor your O2 and N2 loading levels from day to day, there should be no reason why you could dive all the time. Keep in mind that one day of shallow dives (30 - 40') in between might just do the trick, rather than not diving at all.

Enjoy your trip and please let us know how it turns out!!!

 

[jepuskar]

Rick,

Yes, that is a great idea. That is one thing Bonaire has is plenty of shallow diving sites... Ol Blue comes to mind first.

The weird thing about diving that you always have to think about is...you can do 1 dive to 60 feet for 30 minutes and come up bent and then another time do 4 dives a day for a week and not have a problem.....that is just wild.

 

[Damselfish]

Mer,

I appreciate your comments about taking days off and we are planning on doing that. We arrive on Saturday at 3:30pm, so from then until the next morning we wont dive. We leave the following Sunday the 22nd around 4:30pm, so roughly between that time and 4:30pm on the 21st, we wont be diving either. Ofcourse we will have to sleep sometime in these 8 days also, so that is the extent of non-diving activity.

One thing I think i worthwhile doing for us would be to take a break in diving Nitrox about halfway through the trip for a solid 24 hours.

Also, using Nitrox and diving air tables doesn't really give us any significant increase in safety. We each have Nitrox computers and will be watching those very closely and allowing significant time for our safety stops.

If your time off is at the beginning and end of the week, that's not a break. Diving air instead of Nitrox for a day in the middle of the week is not a break either. (Well it's a break from the oxygen, but not the nitrogen.)

On a only one week trip with a lot of diving I might not take a whole day break, but I usually at least take a day where maybe I do a couple in the morning then knock off until the next morning.