Steel 120's

[boulderjohn]

I have not dived Cozumel in many years, but the last few times I was there, I did indeed dive with (and prefer) steel 120s. I also have my own steel 120 twinset that I use for pretty deep deco diving. What follows is my observation of reasons most dive operators don't use them.

• For the overwhelming majority of divers in resort areas around the world, the AL 80 is just fine for standard NDL dives on air. It provides a total dive time that allows them to run a predictable schedule of 2-tank dives. Many dive operators do not want their customers to do 80-100 minute dives because their schedule will not allow it. In fact, the 120's became a significant problem on one trip to Cozumel. The harbor had been closed in the morning, and our trip was postponed to the afternoon. We did the first dive and a long surface interval, as usual. When we got back to the boat, our gear had been setup for the second dive, and we all saw that we only had 3,000 PSI in our tanks. We all complained about it, and the DM lied and said that 3,000 PSI was a standard fill for all tanks. We all knew better. Well, we did the shortened dive and got back to the marina just as night fell. If the DM had simply told us that we had to shorten the second dive to get back by dark, we would have accepted it without a murmur of dissent. The fact that he lied to us about it did not go over well, to say the least.
• If you are going to get the true benefit of the extra gas by staying deeper longer, you need to be diving nitrox. When I used to dive Cozumel regularly, nitrox was by no means common. In my earliest days there, if you wanted to dive nitrox, you were limited to a single tank, used on a second dive. Once when I asked for the nitrox to be used on the first dive while we were on the boat, the DM gave me a stern lecture on how very dangerous it would be on that dive. If I were to lose buoyancy control and drop 20-30 feet below the planned maximum depth, I would die a horrible death in an instant.
• 120's are indeed pretty long. I am just about 6-0, and my doubles really are a bit on the big side for me. They are much too big for many customers. Aldora does provide HP 100s, too, which is a good size for shorter people.
• Steel tanks have an increased maintenance problem because they can rust. I do my own tank servicing, and when I O2 clean my steel tanks, I am very careful to dry them as quickly as possible to avoid rusting. I can just let my aluminum tanks drain if I want. If you are a dive operator that does not do your own filling and maintenance, you have to reply on someone else's carfeful maintenance procedures to make sure your tanks do not fill with rust.
• As ChuckP said, it is much easier for dive shops to use the common pool of fill station tanks than to own their own.

 

[Dave Dillehay]

I think there is some confusion about "steel" 120 tanks. The high pressure ones that Aldora uses are filled to 3450 PSI. The other steel 120 tank is a LP (Low pressure) one at less than 3000 psi. Because the low pressure one has to have more volume to cram in 120 cf of air, it has to be much bigger and heavier than the HP 120. In fact the HP 120 is the same diameter as the aluminum 80 and just a small bit taller.

It is true that it takes a big investment to use the HP 120s ( cost more and die sooner) and getting them filled reliably was a big problem until Aldora opened their own compressor shop (another major investment). But I recognized right away the value of the HP120 to the quality of dive in the early nineties.

With 50% more air and the use of the newly available dive computers, amazingly long and wonderful multi level dives could be enjoyed. Fact is that I brought in the first 50 tanks in my bags on Continental Airlines!

But the HP 120s also have some wonderful buoyancy characteristics. When full they weigh 8 lbs more than an Aluminum 80, that makes getting down a no problem. Then when empty they never become positively buoyant which means you can take 4 lbs off your normal weight belt. Many people can dive with no lead at all (me included and I'm fat).

All in all, I feel proud to have introduced this sort of diving to Cozumel and even though I am no longer involved in the business, I think it great that more and more people are coming to understand the benefits of HP 120s.

Dave Dillehay
Villa Aldora (only)


PS Aldora also uses HP 100s which are much smaller than aluminum 80s, as well as tiny HP 80s,
and suits the tank to the diver. The small 80s are also perfect for shore dives at the Villa Aldora

 

[ReadyTo Dive]

In Cozumel, you do not even try and dive into a strong current.

My last dive was at San Juan and the best one could do was hold position; it is really difficult/nearly impossible to make any mentionable progress against that type/amount of current in the open head on.

 

[Streydog]

My last dive was at San Juan and the best one could do was hold position; it is really difficult/nearly impossible to make any mentionable progress against that type/amount of current in the open head on.

From what I have experienced at San Juan is right after you hit what I call the finger gardens, there is a cut where everything kind of stops, you can look at towards the blue and see a bunch of fish just hanging out. Then shortly after that the reef gets deep and the dive is over no matter what size tank you have.

 

[ggunn]

My last dive was at San Juan and the best one could do was hold position; it is really difficult/nearly impossible to make any mentionable progress against that type/amount of current in the open head on.

If a boat dive plan involves kicking against the current for any length of time, it's a bad plan.

 

[ReadyTo Dive]

If a boat dive plan involves kicking against the current for any length of time, it's a bad plan.

That wasn’t anybody’s plan, not sure why you might have thought it was (I could be misinterpreting that). I remember holding position near the telephone/communications cable and several other times to peek under ledges/etc. but very doubtful that anybody would ever attempt to make diving against the open northern Cozumel currents their actual dive plan.

 

[formernuke]

I don't like 120's. I prefer steel 100's but to each there own.

 

[mediumone]

If a boat dive plan involves kicking against the current for any length of time, it's a bad plan.

Yes.
Changed ops at one point because the DM liked to call us back to look at something. Happened repeatedly, and one too many times. No, we weren't being cowboys and cowgirls off doing our own thing, or require close supervision.

 

[Dave Dillehay]

I don't like 120's. I prefer steel 100's but to each there own.

That is why Aldora offers 3 sizes of HP tanks. 120s, 100s, 80s. Obviously small framed ladies can usually get by with 100s while small kids easily can carry the 80s.

Dave Dillehay

 

[stuartv]

I love my HP120s. Singles and doubles. To me, they are easier to dive with good trim than, for example, my HP100s.

I think the reason more ops don't offer them is simpler than y'all have made it out to be:

1) The market hasn't demanded it.

2) They cost more to buy and they cost more to maintain.

I think that is really all there is to it.

The market hasn't demanded them because the vast majority of Caribbean vacation divers don't know anything but AL80s. So, they do not make tank size a discriminating factor when they are choosing who to dive with. And if having HP120s (and HP100s) isn't going to be a significant factor to the people shopping for a dive op, why would the dive op spend the money?

Major props to @Dave Dillehay for "building it" so "they will come". The bigger tanks and longer dives is why I'm diving with Aldora all next week.

I don't generally have any trouble making my gas last long enough to use my whole NDL - on deeper dives. So, a 120 on a 100' dive is not an advantage to me, over, say, a 100.

What I am especially looking forward to is the shallower dives (say, <60') where NDL is no longer the limiting factor and I can really stay down long enough to use my whole tank (less safety reserve, of course). Then, having 50% more gas than an AL80 will be a REAL advantage!