Overfill at Castaway Scuba

[plot]

Castaway DOES have a 10 fill card for $27.50 or something like that, I want to say. That's $2.80 an air fill or so (there'll be tax on the 27.50). I'm still paying for a full fill on my doubles, but $6 is much better than $10. The only downside is, if I buy the card but don't use it for a while. Money has a time value, if I give them my money than they can use it to invest and make money. If I keep it, I could invest it and eventually make enough money that even paying $5/tank, I would have profit. Granted that could take a while but it's just a fact of life. It's just like prepaying for speedpass or whatnot. That money gets taken out of the bank account and then I can't use it for other things. Also, that money is on the speedpass and I can't get it off, so if I stop using the speedpass I'm screwed.


But it's still a fact: simplest way to get a discount is to buy in bulk and prepay for it.

except the dollar is crap, with inflation if you buy 10 air fills now, in a month air fills might go up to $30 a fill... then you're really saving.

 

[SparticleBrane]

I have said this before, and I am ready for the flames...............

....it is equally as safe (or unsafe, depending on your viewpoint) to overfill an aluminum cylinders as it is to overfill a cylinder made of any other material under the DOT standards. Regardless of the material, they are all subjected to EXACTLY the same qualification tests. ALL OF THEM (even steel cylinders) must fail in a leak-before-burst mode at some time after 10,000 cycles to be approved. If a cylinder never fails during the testing, the test is a failure.

Many will CLAIM that there is some sort of evidence that aluminum is less safe than steel for overfilling, but few can produce anything other than anecdotal evidence. Overfilling cylinders, while done fairly frequently, is entering into completely unknown (from an engineering perspective) territory. I don't know of ANY scuba cylinder company that has completed and published any engineering tests on the impact of overfilling scuba cylinders.

Phil, you took the words right out of my mouth.

Luxfer says their tanks are "cycle tested in excess of 100,000 cycles at service pressure" and says the minimum burst pressure is 2.5x service pressure.

Are we really worried about an Al80 blowing up at 3600 or 3900 psi, when hydro is 5000psi and minimum burst pressure is 7500 psi? Add to that what Phil said, and I think most people in this thread are spreading FUD -- Fear, Uncertainty, and Doubt.


I would have thanked the guy for giving me extra air...

 

[OneBrightGator]

I'm really glad to have two divers that are more educated and experienced in metallurgy and pressure vessels then the entire USDOT and CGA. Excellent.

Are you really getting that much out of jacking up an AL80? A couple extra cubic feet? If you can't do the dive on the tanks you have get bigger tanks or add another one, if you can't do that, then you can't do the dive safely. Is the testing done under real world conditions? Are the tanks banging, bounced and jerked around? Are they subjected to fast fill cycles? Corrosion and wear, salt and sand?

You can call it FUD all you want... but it only takes once to take someone's hand, arm, torso or life... all for a couple cubic feet. FAS, if you ask me.

 

[SparticleBrane]

Aluminum tanks have to go through the same tests that steel tanks do, to be put on the market. People push steel tanks all the time in cave country -- I don't see a huge problem doing the same for aluminum.

I'm not advocating it, especially since you aren't getting that much extra when you overfill an Al80 to ~3600. But honestly, I wouldn't lose sleep over it.

Heck I have had my double Al80s at 4,000 before. :11: Filled to 3600 then I left them in my trunk on the hottest day of the year. I will certainly admit I brought them inside quite carefully and put a few fans on them.

 

[UCFKnightDiver]

as long as your trunk doesnt get direct sunlight it wont get very hot the rest of the car gets hot because the sunlight passes through the windows

 

[eandiver]

Aluminum tanks have to go through the same tests that steel tanks do, to be put on the market. People push steel tanks all the time in cave country -- I don't see a huge problem doing the same for aluminum.

Two different metals... different reactions.

 

[OneBrightGator]

Aluminum tanks have to go through the same tests that steel tanks do, to be put on the market. People push steel tanks all the time in cave country -- I don't see a huge problem doing the same for aluminum.

I'm not advocating it, especially since you aren't getting that much extra when you overfill an Al80 to ~3600. But honestly, I wouldn't lose sleep over it.

That's very interesting, because is still sounds like you are. I mean, hell, if the burst pressure is 7,500, we can go on ahead and jack those babies up to 6,000 easy and get double the dive!

Steel is not aluminum... why don't you take a look at the statistics for tank failures and see how many were steel?

Actually doing it is one thing, acting as the expert and brushing it off to the point of advocation is a whole other thing.

 

[Dive-aholic]

There is a reason why our (college) scuba club negotiates for lower prices. We have ~20-30 members and growing quickly now, so whatever shop we choose to deal with will be our "preferred" shop, and will get a lot of business from us. So they reduce their prices a little bit and we channel thousands of dollars of business to them. Seems like a fair deal to me. If you are talking about one college student, sure, they should pay the same, but when it is a group, there are enormous benefits to a shop to reduce the prices for that group, whether they are college students or a local diving club. A small discount will pay off handsomely when a lot of business gets sent to them.

Flame me all you want, but we have 6 students looking to do OW now with another 3 or 4 on the fence. That's a lot of money now as well as a lot of future money that could be made. Getting a shop to cut us a deal will pay off for them, and they know it.

Not a flame, but shops and instructors don't make a whole lot for instruction. When you take into account the instructor fees, required liability insurance, our own air fills, and time involvement, it's very little. However, I do agree that offering discounts for larger groups is a good business choice. I've been offering college discounts and group discounts for some time now. I don't sell gear so I don't get anything back by doing it with the exception of possibly selling some more instruction.

 

[scblade27]

Castaway DOES have a 10 fill card for $27.50 or something like that, I want to say. That's $2.80 an air fill or so (there'll be tax on the 27.50). I'm still paying for a full fill on my doubles, but $6 is much better than $10. The only downside is, if I buy the card but don't use it for a while. Money has a time value, if I give them my money than they can use it to invest and make money. If I keep it, I could invest it and eventually make enough money that even paying $5/tank, I would have profit. Granted that could take a while but it's just a fact of life.

Wow, busting out the time value of money argument like a true student of finance, your professors would be proud :yelclap:

I see both sides of this story but do agree with offering nitrox by partial fills. I can see leaving air as it is, but the argument w. cavern/cave divers makes since w. nitrox. Also, it just makes good business sense. You may lose a few bucks on nitrox fills, but look at how much the average caver spends in equipment, etc. If they are just holding off to purchase their gas in north florida, it stands to reason that is also where they would do their shopping. If you drop the price of fills here for them, they fill their tanks here, the shop loses $5 on the fill and sells a $1000 can light, or $500 bp/w, or $1500 dry suit, etc. The cave diving thing is expensive and I would think a shop would try their best to capitalize on that market. I just graduated from UCF and am signed up for my first cavern class in a month. I will be in the market for many items. I also knew several students at UCF who bought there stuff in N florida for the same reasons JJW is talking about.

I could be completley off basis, but thats what makes good business since to this finance student. That being said, i have been in the shop a couple times. They treated me well, been very friendly and are literally a mile from where i work. I havnt thrown a lot of business their way (just some tank fill which have always been good), but they may become my shop of choice. as i get into some more serious diving.

 

[LiteHedded]

if I'm going up north I wait till i get there most times