Nitrox 32 first dive, air second dive?

[Lorenzoid]

Consider asking Tres Pelicanos what the majority of their divers do? As someone mentioned, if the other divers in your group are on air, their no-deco time will be the limiting factor for the group.

 

[keesmon]

Consider asking Tres Pelicanos what the majority of their divers do? As someone mentioned, if the other divers in your group are on air, their no-deco time will be the limiting factor for the group.

Thanks Lorenzoid, but Tres Pelicanos is one of the dive shops that let's everyone dive their own profile.
It's one of the many reasons we dive with them.
I will ask the shop, but was hoping to get some insight from divers around the Island.

 

[northernone]

Just popping in here to remind everyone that every dive is a deco dive and NDL limits are arbitrary at best.

Why not enjoy a little more hang time on your safety stop especially towards the end of your week?

Most of the long time divers I've met in cozumel dive air, mainly due to being cheap and easy.

Your personal risk tolerance and dive profile choice is your own.

Regards,
Cameron

 

[nodakdive]

Interesting. The opposite approach of what I was thinking. Let me mull that one over. I like the idea of the added depth safety for dive 1. I have almost run into NDL's on the first dive on air though, and that's using an Oceanic Computer.

I should also clarify that when I say I don't run out of NDL time, I mean throughout the day or the dive trip. It's not horribly rare for me to run out of NDL on 1st dives. One of the reasons is that we often dive well below 80 feet, and, I have a very conservative computer. I think Dave Dilehay commented directly about the Mosquito on another post, saying something to the effect of "...it treats all dives like decompression dives...". This has been my experience. When I go beyond the NDL on a deep dive and the computer starts requiring more than a 3 minute stop, by the time I hit the safety stop, all I owe is the mandatory 3 minutes for having gone below 100 feet. On second dives, I never run out of NDL or get very close to running out of NDL.

Would you rather run into a massive down current on a wall with a gas that becomes a PPO issue at 120 feet, or 220 feet?

 

[doctormike]

Thank you Tursiops.
I have put it into the planner, using last years dives that got me closer to NDL than I wanted, and have done the equivalent planning if I had used EAN32 on the first dive. Diving EAN21 on the second dive seems to be OK.
My question is:
What do other divers (Cozumel Nitrox certified veterans diving AL80's) do for their two dives?
This question I cannot ask myself. I am simply asking for the collective experience of the regulars to Cozumel. Thank you

Sorry, I'm really having a hard time understanding what you are looking for. What gets you close to your NDL is the time you spend underwater and your depth for a given mix. So whether you are diving Air, 32, or 36, your profile will determine your NDL.

If you switch to nitrox, your NDL will be longer for a given dive. You can then chose whether you want to spend more time underwater (compared to air) with the same risk of DCS, or spend the same amount of time underwater as the air dive with a reduced risk of DCS.

To answer this question, I always dive nitrox in Cozumel - it's a pretty small percentage of the overall trip cost. Most people who dive nitrox choose the longer bottom times (assuming that they aren't limited by gas consumption or the logistics of group diving), since the risk of DCS in a recreational dive up to the NDL is pretty low. If I traveled all the way to Cozumel, I would want to maximize that dive time myself.

But using nitrox would give you those two options - you would need to decide if either of those is worth the extra money to you.

 

[keesmon]

To answer this question, I always dive nitrox in Cozumel -
Thank you DoctorMike. Would you mind sharing the percentages you typically use?

 

[Trailboss123]

Thanks Lorenzoid, but Tres Pelicanos is one of the dive shops that let's everyone dive their own profile.
It's one of the many reasons we dive with them.
I will ask the shop, but was hoping to get some insight from divers around the Island.

I prefer to dive Nitrox 32 on dive 1 in order to accommodate for the deeper profiles and the length of time spent at depth. Dive 2 is done on air and no deco limits have never been an issue given the typical dive profiles on 2nd dives. This is assuming an appropriate surface interval. Very important to be conscious of switching your computer from 32 to 21 in this scenario. It is very easy to forget to make the change between dives and that leads to the obvious issues. If I am doing 3-4 dives a day or in a given day, then that is another story.

 

[uncfnp]

Hi keesmon,

Timely question. I can't tell you what the regulars do but I can tell you what I have learned so far diving with 3 P's this week.

We always dive Nitrox wherever we go and diving with Aldora last year it was a good choice since with my computer set conservative I was bumping (and occasionally a little more then that) my NDL.

So when we booked with Tre Pelicanos this trip I was adamant for Nitrox for both of us. 36's for me and I have had no issues with MOD's for any of the 8 dives thus far. In fact I don't think I have been beyond 85 feet.

Eric dives DSAT and could probably have gotten away with air both dives but we requested nitrox for him as well, the 36 and 32 combo. But today they did not have the tanks and he ended up with a 36 and then air for the second dive with no NDL issues. Not even close. Next trip I think he will go with this combo for the biggest bang for the buck and because his Nitrox 100's are just dang hard to come by.

Of course you millage may vary depending on the algorithm of your dive computer.

 

[uncfnp]

I looked back at my dive logs for Aldora and my deepest dive was 95 feet and that was Punta Sur (not DT).

If you have a 36 and air on board and find out the first dive planned is questionable on 36 just switch over to the air tank then dive the 36 second.

 

[tomhooper]

I have used 32 and 36. If you are doing a normal Cozumel profile, you shouldn't get too deep for either. That said I usually dive air.
Only thing about Nitrox is that you don't get that tired, washed out, feeling after diving.