Aluminum 80s versus larger steel tanks

[Ron Lee]

I am beginning to lose track of who has said what in this thread.

I am getting sense that the general drift is that there is no advantage to steel 120s because you don't get any longer bottom times than with an AL 80, and if you do use them, you have a higher risk of DCS because of the increased bottom times. Or am I misreading this?

I would say that the statement above is 100% opposite of the truth.

 

[boulderjohn]

I would say that the statement above is 100% opposite of the truth.

I guess I'm confused then. What do you perceive to be the general drift of this conversation?

 

[Mossman]

I guess I'm confused then. What do you perceive to be the general drift of this conversation?

I perceive the general drift of the conversation to be that the divers who currently prefer to dive steel 120s in Cozumel defend their reasons for doing so while those who currently prefer not to dive steel 120s in Cozumel defend their reasons for doing so and I doubt either side has changed anyone's mind on the subject.

For instance, I appreciate that 120s may allow one to exceed the NDL easier than with an 80, that they cost more, and that some people can get dives just as long using a 100, 80, 63, or a spare air. But I'll still spend the extra $$ the next time on the island because I personally feel I get my money's worth and to me the benefits outweigh the risks and disadvantages.

While I don't know Ron Lee very well, I believe I'm safe in assuming that he personally feels that he gets his money's worth with the steel 120s and to him the benefits outweigh the risks and disadvantages.

 

[boulderjohn]

While I don't know Ron Lee very well, I believe I'm safe in assuming that he personally feels that he gets his money's worth with the steel 120s and to him the benefits outweigh the risks and disadvantages.

Understandable.

In that case, he must also wonder, as I do, about the opposing arguments that seem to be simultaneously stating that the larger tanks do not provide greater bottom times and that they also increase the risk of DCS because of increased bottom times.

As I said, I am not sure what is being said here now.

 

[Skittl1321]

I don't think anyone has said larger tanks don't provide greater bottom times (except a small female who had to wrestle with the weight of her tank- and obviously exerting energy is going to take more air). I think people have said that with already long bottom times, the larger tanks aren't necessary in a place like Cozumel.

The only reason I'm not interested in a 120 is money. I suspect I wouldn't like it because of anxiety- I have no interest in a 2 hour dive...but 90 minutes sounds okay, maybe.

I also don't think that those that like 80s are trying to convince those who like 120s that 80s are better. Merely that the presumption that everyone should like a 120 better is a bit ridiculous, and when people ask for dive op suggestions saying "they have 120s" doesn't automatically make the op a best fit for everyone.

 

[Tony387]

I agree with much of what has been said regarding the use of larger and tanks and an increased risk for DCS. I may be wrong, but it is my belief that many of the posters in this thread are not at all characteristic of the average diver in Cozumel. I would also guess that the number of Cozumel divers who could benefit from the use of larger steels, and who could do so with absolutely no increased chance of injury to themselves, are but a small percentage of the total number of Cozumel divers. In my opinion, the vast majority of the divers who travel to Cozumel are "vacation" divers who take one or two excursions a year, and that's all the diving they do. I know divers in Texas who don't dive anywhere else. It makes no sense to me, but that is what they do. I think when this type of diver makes up the majority of a dive op's customer base, diving within NDLs and avoiding DCS hits, etc., have to be real concerns.

As for me, I love my Steel 72.

 

[halocline]

As for me, I love my Steel 72.

That's what I use in aquarena 90% of the time, I love them too.

 

[Mossman]

Understandable.

In that case, he must also wonder, as I do, about the opposing arguments that seem to be simultaneously stating that the larger tanks do not provide greater bottom times and that they also increase the risk of DCS because of increased bottom times.

As I said, I am not sure what is being said here now.

If he is uncertain about his convictions, then yes, he might still wonder. As for me, I do not. I have done many a dive on an AL80, in Cozumel and many other locales, with camera and without camera. In Cozumel, I have done dives on AL80s, AL100s, and steel 120s. To me, there is no doubt that the 120s provide me with the greater bottom time I need for my profiles, which usually include a fair bit of swimming against current in order to stay in one place long enough to get decent macro shots. As for the increased risk of DCS because of increased bottom times, I always mitigate with nitrox where possible, and because I do know and respect my conservative dive computer, I don't fear any increased risk of DCS because I fall within the margins where DCS is simply a 1/10,000 chance I take whenever I dive. That the longer times may increase the risk of DCS for divers that are clueless in general about how their profiles and diving behavior affects their risk is simply not my problem. After all, if it were up to me, I'd decrease the risk of DCS and all other scuba-related maladies simply by banning beginners and other likewise clueless divers from diving in Cozumel period.

---------- Post added May 21st, 2014 at 01:13 PM ----------

I don't think anyone has said larger tanks don't provide greater bottom times (except a small female who had to wrestle with the weight of her tank- and obviously exerting energy is going to take more air). I think people have said that with already long bottom times, the larger tanks aren't necessary in a place like Cozumel.

I also don't think that those that like 80s are trying to convince those who like 120s that 80s are better. Merely that the presumption that everyone should like a 120 better is a bit ridiculous, and when people ask for dive op suggestions saying "they have 120s" doesn't automatically make the op a best fit for everyone.

I'll agree with your second premise. 120s aren't for everyone. I'm 6'1", so the longer heavier tank stabilizes me underwater better than an AL80 and I prefer the buoyancy characteristics as well. And I like the extra air. For someone with excellent air consumption who doesn't like the characteristics of higher-volume steel tanks and who are otherwise allowed to dive "their tank", it makes no sense for them to pay extra. For someone who simply doesn't care about getting in longer dives and is happy with the bottom time they get out an AL80, again it makes no sense for them to pay extra.

 

[cvchief]

As for the increased risk of DCS because of increased bottom times, I always mitigate with nitrox where possible, and because I do know and respect my conservative dive computer,

and stay hydrated, don't drink too much and get plenty of sleep?

 

[Mike]

I would not assume that if the big steel tanks are eventually used by more dive ops and by a more widespread group of divers, all the dive ops will follow Aldora's practices to offset the potential increase in risk in using bigger tanks to extend depth/bottom time.

I totally don't get how the size of my tank is the factor in staying out of deco.

Depth and Time. There are 2 factors (3 actually if you count nitrogen loading from previous dives) that effect how soon you approach NDL, time is just one of them. I can go into deco quicker due to depth than time and depth has no connection to the tank on my back.