Nitrox for shallow water artifact diving??

[calabash digger]

15 to 20 minutes

 

[AfterDark]

15 to 20 minutes

Nice jug by the way!

 

[ginti]

15 to 20 minutes

Were you answering my question? Maybe I wasn't clear, sorry...

For surface interval, I mean the time between two consecutive dives. So you do one dive that lasts between 90 and 120 minutes, then you go out of the water, you wait 20 minutes and then you do another dive of roughly 90/120 minutes?

And how many dives per day?

 

[ginti]

90 to 120 minutes on a 10 to 25 ft dive. I was taught at these depths there was really no risk of DCS on a two tank dive. ???? I would say 80% of my dives have been in the 20 to 25 ft range and that depth changes up and down a lot sometimes. I climb up and down the wall looking for artifacts so I might be at 25 feet one minute and in five feet of water few minutes later.
I can get Nitrox fills very easily about a mile from my house...couple dollars more I think for each tank...

As Duke dive medicine clarified, this isn't true; but 90/120 minutes should be ok, just check your course material or try to insert those data in a deco-software.

Also, one thing you should pay a lot of attention to is to avoid the so-called yo-yo/saw-tooth profiles. As far as I understand, they can be very dangerous in this depth range.

 

[AfterDark]

90 to 120 minutes on a 10 to 25 ft dive. I was taught at these depths there was really no risk of DCS on a two tank dive. ???? I would say 80% of my dives have been in the 20 to 25 ft range and that depth changes up and down a lot sometimes. I climb up and down the wall looking for artifacts so I might be at 25 feet one minute and in five feet of water few minutes later.
I can get Nitrox fills very easily about a mile from my house...couple dollars more I think for each tank...

You are in more danger driving to the site than you are of DCS on those dives. I am in fact doing at least one of those dives later today. Edit: On 21%

 

[calabash digger]

2... I have pulled 3 before but that was in 20ft average and 40 degree water. I was finding some great artifacts that day. Also did a lot of spotting that day so bottom time would have been way shorter .. Up and down getting in the boat and going to another spot to check. Slept good that night!!

 

[ginti]

2... I have pulled 3 before but that was in 20ft average and 40 degree water. I was finding some great artifacts that day. Also did a lot of spotting that day so bottom time would have been way shorter .. Up and down getting in the boat and going to another spot to check. Slept good that night!!

I really do not manage to follow the numbers, sorry... I think it's because I am a bit tired now, working too much

Quoting myself, even if I hate to do it:

here's what I would do if I were you:
- write down the duration of my average and my most extreme dives;
- write down how often I do repetitive dives and the associated surface intervals;

If decompression limits the duration of your dives, or if you want to reduce the surface intervals, you should go for nitrox. Even if you plan to use nitrox only a couple of times per year, you need to take the course.

Naturally, you need to compare the numbers of your surface intervals with the material of your courses!

About the fatigue issue, keep in mind that it can be due to the workload of the dives, and not because of nitrogen.

However, since so many people report feeling better, you can try if you really feel tired after these dives. Without any science backing the right answer, you need to try yourself

 

[halocline]

I was talking to a buddy about being so tired after chasing artifacts in shallow water and burning down two 133 s which last forever in shallow water...My dives are forty feet or less and most of the time 20 ft or less. He told me nitrox diving would help with the next day tiredness...What do you guys think??

I read through about half of this thread and you have received some good advice about nitrox. Sorry if someone else has already brought this up, but probably you can improve the way you feel after diving by doing two things; limiting the up-down-up-down profile of your dives, which since you are looking for artifacts might involve following the bottom, and making sure you ascend very very slowly, especially from 20 feet to the surface. Your fatigue is probably a combination of surfacing with enough N2 loading to put a bit of stress on your tissues, and maybe a bit of low-level baro trauma, which is very easy to get when you're shallow and changing depth frequently.

I would try doing at least 10 minutes of stop at 10 feet at the end of one of your dives, then take a full minute (or longer) to surface from 10 feet. Try that and see if it helps, my guess is that it will.

Using nitrox might also help, but there is the cost and the additional O2 load to consider if you are doing really long dives.

 

[Divin'Papaw]

90 to 120 minutes on a 10 to 25 ft dive. I was taught at these depths there was really no risk of DCS on a two tank dive. ???? I would say 80% of my dives have been in the 20 to 25 ft range and that depth changes up and down a lot sometimes. I climb up and down the wall looking for artifacts so I might be at 25 feet one minute and in five feet of water few minutes later.
I can get Nitrox fills very easily about a mile from my house...couple dollars more I think for each tank...

This is the part that concerns me. If anything is going to cause you an issue it would be a sawtooth profile with lots of depth changes up and down over the course of a 2 hour dive. For me ... and this is just me ... I would be using nitrox for this reason alone. To minimize tissue loading as much as possible given the sawtooth nature of your profiles.

ADD: I've known instructors who have gotten bent doing repeated CESA dives on air with multiple students from 20 ft.

 

[ginti]

This is the part that concerns me. If anything is going to cause you an issue it would be a sawtooth profile with lots of depth changes up and down over the course of a 2 hour dive. For me ... and this is just me ... I would be using nitrox for this reason alone. To minimize tissue loading as much as possible given the sawtooth nature of your profiles.

ADD: I've known instructors who have gotten bent doing repeated CESA dives with multiple students from 20 ft.

Going back to our previous discussion, this is a valid reason