Nitrox best mix question

[TSandM]

Focus on the readiness, not the dive.

Beautifully said, Reg!

 

[Blackwood]

You are correct, I was in error. PADI does not include the ascent time but they do include the descent.

Richard

Regardless, I agree with you. 3-6 minutes it hardly worth it (unless there's something to see on the way up).

 

[black1]

Again first let me say thank you to all of you for your tips/advice and concerns for me and my expierience, it means alot to me. A little background about me and expierience is that i have done many many dives since my certification (1984, i was 14) and then i lost interest for awhile, im now getting back into diving, decided to do my AOW and start logging my dives as i wish i did in my younger days. I have had expierience with things such as very bad current, heavy seas and other potentialy dangerous circumstances which were not always the smart route but were what they were, I do not take risks anymore and love my life and my wife and am happy sleeping in my bed at night which im sure you all understand what i mean. Iam new to Nitrox (2years) and most dives spearfishing have been 60 to 80ft using EAN32 AND EAN36 always in a safe PO2. I have spoken to my instructor who assured me she never meant for us to go below 110ft on this dive, the tower rest in 110ft and we can see plenty from that depth, no penetration of course, no bottom. This made me happy to clear this up, we only spoke of the dive and had not had the time to discuss over the weekend so this was why i was concerned and did not no if she meant 145ft were going or what. I will be using EAN30 at PPO2 1.4 = 121ft which is safe and fine by me, it will be called off and we will drift a shallower reef if the current is anything bad, the 2nd dive is a nice reef in 70 to 80ft no more and i will use EAN32 for this one, well clear and safe for an easy drift. Im in no rush to simply get another card for my wallet and will take my time and enjoy and most of all get expierience from the AOW and then Advanced Nitrox/Decompression procedure class which will be afterwards for more expierience, again thank you all gentleman for your help and i will let you all know how it goes, in the meantime here is a link to a video of this particular wreck, enjoy.


YouTube - Wreck dive 3

 

[Reg Braithwaite]

i have done many many dives since my certification (1984, i was 14) and then i lost interest for awhile, im now getting back into diving, decided to do my AOW and start logging my dives as i wish i did in my younger days. I have had expierience with things such as very bad current, heavy seas and other potentialy dangerous circumstances... most dives spearfishing have been 60 to 80ft using EAN32 AND EAN36 always in a safe PO2. I have spoken to my instructor who assured me she never meant for us to go below 110ft on this dive, the tower rest in 110ft and we can see plenty from that depth, no penetration of course, no bottom...

Well! Now I feel like an ass, you have much more experience than I have!

:bonk:

 

[ScubaSteve]

Well! Now I feel like an ass, you have much more experience than I have!

:bonk:

While that may be, your reccomendations and advice was still very solid IMO. And I agree with Lynne about:

Focus on the readiness, not the dive.

That is a keeper and one that should be used much more frequently.

 

[Walter]

I have spoken to my instructor who assured me she never meant for us to go below 110ft on this dive, the tower rest in 110ft and we can see plenty from that depth, no penetration of course, no bottom. This made me happy to clear this up,

That's a much better plan than the one originally discussed, but it still violates standards. That's never a good idea.

 

[AzAtty]

That's a much better plan than the one originally discussed, but it still violates standards. That's never a good idea.

When I'm considering a training site, I prefer to have the seafloor at the maximum depth for the dive. That way, your students can only go deeper if they bring a shovel. I would take Walter's advice on the alternate dive site.

 

[Teamcasa]

When I'm considering a training site, I prefer to have the seafloor at the maximum depth for the dive. That way, your students can only go deeper if they bring a shovel. I would take Walter's advice on the alternate dive site.

Exactly. If the possibility to do crazy things exists, people will somehow find a way to do it. A few minutes browsing the Accidents and Incidents and it's sub forums will drive that point home.

 

[down4fun]

Hello all, this Saturday im doing a wreck dive off of Pompano Beach Florida called the Guy Harvey, it rests in 140ft of water and this is part of my AOW Deep dive, ive done 106ft the weekend before perfectly and i used a nitrox 36% for that which is my usual mix. Im not sure we (my instructor/friend) will hit bottom but probably close to it say aroun 135ft and she suggested to fill my tank with EAN30 for this dive, at PPO2 1.6= 143ft, I would like to stay in the PPO2=1.5 range for comfort (maybe current,challenges, etc) and this gives me 132ft as a MOD. My question is should i stay at this mix as she suggests or should i use EAN28 which gives me a PPO2= 1.5 at 143ft. and gives me a little safety room in case there is a strong current or some type of strenous activity that may come about?

Thank you all very much for your advice and concern, the agency im using is P.A.D.I. and although i feel i have expierience it did alarm me and make me question as soon as i heard the mix for that dive and i questioned the judgement. I will be speaking to her soon and will ask plenty of questions and voice my concern. I would like to dive to the recreational limit of 130ft but only using a PPO2 of 1.4 for safety reasons, the area off of Pompano/Ft Lauderdale as anyone familiar knows can have and usually does have a strong current around the wreck sites and pushing the PPO2 to 1.6 is not being safe in my opinion and that is the only opinion i go by. If we talk and she says it will only be to the recreational limit at 130ft the i will give it more thought and will use either a 26 or 28 and no more higher mix, i use HP Steel 120's but safety is my main concern and what i abide by when diving, again thanks all. For those who have dove it what are your thoughts on it, thanks.

Again first let me say thank you to all of you for your tips/advice and concerns for me and my expierience, it means alot to me. A little background about me and expierience is that i have done many many dives since my certification (1984, i was 14) and then i lost interest for awhile, im now getting back into diving, decided to do my AOW and start logging my dives as i wish i did in my younger days. I have had expierience with things such as very bad current, heavy seas and other potentialy dangerous circumstances which were not always the smart route but were what they were, I do not take risks anymore and love my life and my wife and am happy sleeping in my bed at night which im sure you all understand what i mean. Iam new to Nitrox (2years) and most dives spearfishing have been 60 to 80ft using EAN32 AND EAN36 always in a safe PO2. I have spoken to my instructor who assured me she never meant for us to go below 110ft on this dive, the tower rest in 110ft and we can see plenty from that depth, no penetration of course, no bottom. This made me happy to clear this up, we only spoke of the dive and had not had the time to discuss over the weekend so this was why i was concerned and did not no if she meant 145ft were going or what. I will be using EAN30 at PPO2 1.4 = 121ft which is safe and fine by me, it will be called off and we will drift a shallower reef if the current is anything bad, the 2nd dive is a nice reef in 70 to 80ft no more and i will use EAN32 for this one, well clear and safe for an easy drift. Im in no rush to simply get another card for my wallet and will take my time and enjoy and most of all get expierience from the AOW and then Advanced Nitrox/Decompression procedure class which will be afterwards for more expierience, again thank you all gentleman for your help and i will let you all know how it goes, in the meantime here is a link to a video of this particular wreck, enjoy.


YouTube - Wreck dive 3

I am not trying to just be a jerk here but if I were you I would seriously rethink this dive. I understand that you were certified and had many, many dives at that time. But if I read your post correctly you have 24 dives since getting back into diving. This wreck is not something I would approach with so few dives under my belt since getting back to diving. You also mention that you did your nitrox 2 years ago, I am wondering if that is the time period that you have accumulated your 24 dives? 2 years? If so that is not what I would call real regular diving, especially here in south florida. There are many great AOW wrecks in this area that might be better suited for you dive such as The Rodeo 25, The RSB1 or The Capt. Dan. The Guy Harvey is beyond AOW. Plus as you have already mentioned that the wrecks in this area can have strong current. Also that fact that you are questioning your instructors decision and your own comfort level has almost turned this into a "trust me dive" Ultimately it is up to you. I would urge you to take you time do some of the wrecks I mention and work up to the Guy Harvey.

If you do decide to do it I agree with Walter take a back gas that does not exceed you wanted PPO2 when reaching the deepest possible depth on the wreck, which in this case is 140ft. Even though you plan not to go beyond 110ft doo-doo happens...plan for it.

 

[ligersandtions]

When I'm considering a training site, I prefer to have the seafloor at the maximum depth for the dive. That way, your students can only go deeper if they bring a shovel. I would take Walter's advice on the alternate dive site.

I agree whole heartedly with this. I have a friend whose instructor (idiot) was planning on taking him and his wife on their AOW deep dive (and Nitrox dive - 36%) to 100 feet....on an oil rig dive, where the ocean floor was 600+ feet down. I cautioned him that not only was he doing a dive on a mix that was going to exceed the recommended MOD, but that there was also no "safety net" for them to rely on....and with only 10-15 dives under their belts, I highly doubt their buoyancy is worth a damn.

I know the OP has resolved some of his issues with the dive....but I would also consider finding a new instructor. IIRC, the instructor wants you to exceed 1.4 pO2 during the "working" part of the dive, will be exceeding the PADI max depth for the AOW deep dive, and is planning on having the dive be more "mid-water" than not. Just my opinion....take it for what it's worth.