To Rent Or Buy, That is The Question?

[CompuDude]

Depends on how much you dive, how often you dive, and whether your local diving conditions make steel or aluminum preferable.

In cold water, steel tends to have much better buoyancy characteristics compared to aluminum, as it can help remove weight from your belt, needed to sink drysuits or thick wetsuits. In warm water diving, sometimes aluminum actually makes more sense.

Aluminum is a lot cheaper than steel, but you can get a lot more gas in a steel cylinder that weighs the same or less, and is sometimes smaller (or holds a LOT more gas).

So if you're renting and happy with aluminum, the pure economics are a lot better for buying compared to steel. Steel costs more, but brings a lot of it's own advantages, and they're often hard to rent.

I prefer the convenience others have mentioned: No rush to return your tanks, easy to refill on your own schedule, you can keep them full and be ready to dive on a moment's notice. Having my own tanks means I don't have to plan a trip to the dive shop everytime the thought of diving crossed my mind, so it has actually vastly increased the number of dives I do a lot more than I thought it would have.

You can keep air in tanks for 6 months no problem, more than that may be ok, but I wouldn't trust it. If you know you are having an extended off season, however, you can store them indefinitely with 300-400psi of air in them, and fill them when you're ready to return to diving. My tanks seldom have air in them for more than a month... usually considerably less!

 

[Aaagogo]

if you want to own tanks, go for no smaller than steel 95's and make sure u buy LOW PRESSURE steel tanks

Ironhed mentioned that special deal out at a LDS at port orange, sadly it's over, but it might be back next year

here's a couple of reason for purchasing LP STEEL 95's (or larger) vs other tanks.

1st of, steel tanks will be less bouyant than a AL80 after your dive which would equate to less weight in your weight belt which would equate to better trimm which would equate to more bottom time becase u are carrying less weight.

2nd, do not ever, never ever, NEVER EVER purchase HIGH PRESURRE TANKS, i cannot stress that enough...

reason;

HP STEEL 120 cuft - you will ONLY get 120cuft of air if you leave the dive shop with 3500psi COLD in the tank

LP STEEL 120 cuft - you will only get 120cuft of air if you leave the dive shop with 2640 psi COLD in the tank

do the math and also not many dive shops fills tanks to 3500psi COLD

3rd, let say you pay to go on a cattle boat, plus gas for your car and other incurred expense, in the end, you use an AL80 which gives you about 20 mins bottom time @ about 80-100ft depth with a SAC rate about 0.7 which around the average for recreational divers. Going thru all that trouble just to spend 20 mins at the bottom???

However owning a larger capacity tank, would give you more bottom time. Haven't we all looked at our SPG's and wish that the gauge was still above 1000psi so that we can stay for a tad longer rather than having to call the dive at when it dips to 1000psi

4th - not many LDS rents or even owns steel tanks, even if they do, they are of very limited numbers and more often than not, for those that know what they are doing, those steel tanks get rented out quick

5th - if you have all your personal gear, bc, regs and wetsuit and everything and have a friend with a boat that goes diving or stays real close to a dive charter, the more reason you should own your own tanks, so you can always go diving at any time and not have to ponder if you can make it down to the dive shop in time after work to rent some tanks.

 

[CompuDude]

if you want to own tanks, go for no smaller than steel 95's and make sure u buy LOW PRESSURE steel tanks

Ironhed mentioned that special deal out at a LDS at port orange, sadly it's over, but it might be back next year

here's a couple of reason for purchasing LP STEEL 95's (or larger) vs other tanks.

1st of, steel tanks will be less bouyant than a AL80 after your dive which would equate to less weight in your weight belt which would equate to better trimm which would equate to more bottom time becase u are carrying less weight.

2nd, do not ever, never ever, NEVER EVER purchase HIGH PRESURRE TANKS, i cannot stress that enough...

reason;

HP STEEL 120 cuft - you will ONLY get 120cuft of air if you leave the dive shop with 3500psi COLD in the tank

LP STEEL 120 cuft - you will only get 120cuft of air if you leave the dive shop with 2640 psi COLD in the tank

do the math and also not many dive shops fills tanks to 3500psi COLD

3rd, let say you pay to go on a cattle boat, plus gas for your car and other incurred expense, in the end, you use an AL80 which gives you about 20 mins bottom time @ about 80-100ft depth with a SAC rate about 0.7 which around the average for recreational divers. Going thru all that trouble just to spend 20 mins at the bottom???

However owning a larger capacity tank, would give you more bottom time. Haven't we all looked at our SPG's and wish that the gauge was still above 1000psi so that we can stay for a tad longer rather than having to call the dive at when it dips to 1000psi

4th - not many LDS rents or even owns steel tanks, even if they do, they are of very limited numbers and more often than not, for those that know what they are doing, those steel tanks get rented out quick

5th - if you have all your personal gear, bc, regs and wetsuit and everything and have a friend with a boat that goes diving or stays real close to a dive charter, the more reason you should own your own tanks, so you can always go diving at any time and not have to ponder if you can make it down to the dive shop in time after work to rent some tanks.

I strongly disagree with your "warnings" re high pressure steel.

It's true that you only have the full capacity if you leave the shop with 3500psi (3442, whatever) cold. It's also true that you will still have a LOT more gas than your average rental Al80 even with only 2800psi of gas. It's also true that HP tends to weigh less and be smaller than LP.

Pick you poison. I'd rather have my HP119 that has 120cf of gas at 3442, but still has 100cf of gas at 2900, 104cf at 3000, 114 cf at 3300 (a far more frequent situation), etc. than lug around an LP95 that is similar in size and weight but cannot be pumped up to the higher capacity without overfilling and thus shortening the life of the tank.

An LP120 is ENORMOUS and HEAVY as H***.

 

[Aaagogo]

^ with regards to the HP and LP steel tanks,

where did u hear that by overfilling the particular faber LP tanks, u are shortening the life of the tank?

what are they actually rated at? originally designed and rated for, not the DOT rating. put that aside on the technicality of rating and what not

say there's a HP and LP tank, both 120cuft, both sitting on the boat, HP is full, 3500 pounds, LP is filled to 3000psi. Someone bumps into em and they both lost 300 pounds. how much air is left in both tanks?

i dont' deny that the HP weigh less and is smaller in size, but the mere couple of pounds difference between the HP and LP and less than 1 inch in diameter is not as important when compared to the vast change of bouyancy is smiliar to that of an AL tank???

NOTE: The LP steel is slightly -ve bouyant at empty, the HP steel and AL are both +ve bouyant at empty

on top of all that, isn't the main reason why when someone purchase their own tanks is because they want more air than what the AL80 carries. so since it boils down to which one will hold more air, isn't the choice clear?

oh and this ->114 cf at 3300 (a far more frequent situation), aren't u better off purchasing the AL 100 which gives u 100 cuft at rated pressure of 3300.

end of the day, you pay so much for a 120cuft cylinder and then turn around and are restricted by so many factors to actually have 120cuft of gas on ur back when you jump into the water......

 

[greg454]

Good threat. I'm conflicted.

http://www.joediveramerica.com has amazing deals in packages.

Specially their basic package. A part of me really wants to buy equipment, just the joy of ownership, being able to say "this is mine, mine, mine!"

But I'm afraid that if I buy it, I'm gonna have to dive many times to justify the $400 to $600 expense. Ironically, I already spent $400 on an AOW course that will allow me to dive 6 times. Haven't done the course yet, I start this saturday.

On the other hand, ownership can save you between $30 and $60 each time you go diving.

I also wonder if I should buy a dive computer first, and then a dive package.

 

[Aaagogo]

i always say this to new divers or students;

People say you can't buy time, but this(i show them a dive computer) is buying time, you'll get more bottom time.

i'm sure your instructor has in some point in time during you open water class mentioned about the difference between a flat/square profile that the dive tables are and how a computer gives you credit for when your depth changes.

IMO, if you are looking to go all out and have your own dive gear you might wanted to speak to your LDS and see if they can give you a package deal if you get everything together, i'm sure that they will be able to cut u a better deal if you get an entire head to toe package.

however, if you are looking at buying in parts, then go for a computer first. u'll get more bottom time out of it

 

[CompuDude]

^ with regards to the HP and LP steel tanks,

where did u hear that by overfilling the particular faber LP tanks, u are shortening the life of the tank?

I'll assume you're serious. Ask anyone who runs a hydro facility whether or not overfilling tanks - of ANY make - shortens their life. Also, feel free to check manufacturer's documentation on the subject. This isn't speculation. Feel free to search around SB, too... this question has come up before.

what are they actually rated at? originally designed and rated for, not the DOT rating. put that aside on the technicality of rating and what not

Again, see manufacturer literature to determine ratings. The ratings are then stamped on the neck of the tank. Just because it won't explode when filled to 5000+ psi (such as what they do during a hydro test) doesn't mean it is a good idea to fill beyond the rated capacity on a regular basis. (There is a special variance allowed to accommodate hot fills, but other than that, you ARE shortening the life of the tank by overfilling.)

say there's a HP and LP tank, both 120cuft, both sitting on the boat, HP is full, 3500 pounds, LP is filled to 3000psi. Someone bumps into em and they both lost 300 pounds. how much air is left in both tanks?

Why would both tanks lose the exact same PSI of gas?

But let's go with your scenario where somehow the HP tank loses 300 psi (to 3200psi) and the LP tank loses 300 psi (let's assume we're talking about an LP121, because those are the figures I have handy, at 2640psi for a full fill) to 2340psi. Your HP119 tank at 3200psi would have 111cf of gas, compared to your LP121 tank having roughly 107cf of gas at approx 2340psi.

i dont' deny that the HP weigh less and is smaller in size, but the mere couple of pounds difference between the HP and LP and less than 1 inch in diameter is not as important when compared to the vast change of bouyancy is smiliar to that of an AL tank???

NOTE: The LP steel is slightly -ve bouyant at empty, the HP steel and AL are both +ve bouyant at empty

Um, no.

Aluminum 80 tanks are buoyant empty, usually about +4. Steel tanks, HP or LP, are almost always either neutral or negative (most -1 to -3lbs) when empty... with one interesting exception I'll note below.

I suggest you study this chart before making any more statements: http://www.techdivinglimited.com/pub/tanks.html

on top of all that, isn't the main reason why when someone purchase their own tanks is because they want more air than what the AL80 carries. so since it boils down to which one will hold more air, isn't the choice clear?

Sure. If you want more gas than an AL80, buy a bigger tank, and probably steel since Aluminum tops out at 100. That's the answer. But HP steel vs. LP stell is an entirely different question. An LP121 holds a whopping 2cf of air more than an HP119, but is considerably bigger externally. An HP130, OTOH, holds 9cf of gas more than the LP121... and it's several inches shorter, and weighs several pounds less on land. And interestingly, the Worthington LP121 is +1 positively buoyant, while the HP130 is -2 negative. (Other types of LP121 are negative, like other steel tanks, however)

oh and this ->114 cf at 3300 (a far more frequent situation), aren't u better off purchasing the AL 100 which gives u 100 cuft at rated pressure of 3300.

Well, in one case you have 100cf of gas at 3300psi, the the case of the HP120 you have 114cf of gas at 3300. If indeed your goal is more gas, then as you say, isn't the choice clear?

end of the day, you pay so much for a 120cuft cylinder and then turn around and are restricted by so many factors to actually have 120cuft of gas on ur back when you jump into the water......

There's no doubt the steel tanks cost more. But the cost difference from HP to LP isn't large. Are you trying to compare steel vs. aluminum, or Steel HP vs. Steel LP?

There's also the fact that steel tanks last longer and have a higher resale value. Many, many steel tanks over 30 years old are still in service, while 10 years is considered the max for aluminum. As a result, steel has a higher resale value, too.

There are indeed many questions worth considering when choosing to buy a tank. Just be sure you are asking the right questions... and have access to the right answers.

Many people like LP better than HP. But I suspect there are reasons other than the ones you cited for their decisions. For me, I like the smaller size and weight of HP, whether or not I get as full a fill as possible in every scenario. If you choose otherwise, I'm happy you have found something you like. Just please give factually valid answers when others ask for advice.

 

[Aaagogo]

i shall step away from this discussion, there are many things due to liability and industrial standard, i cannot reveal, but those who know the truth will know what is the actual capabilities of the faber LP steel tanks that i'm talking about.

i'm only talking about faber tanks and not steel tanks from other makes.

have you yourself tested out the bouyancy characteristics of the tanks or are u just reading em off the chart?

unless my eyes are lying to me or there might be an additional weight stuck to the tanks when i'm filling them, maybe i should take a picture or the bouyancy characteristics of the HP, LP and AL tanks when they are empty for you to visually take a look rather than looking at figures and charts.

i saw and noted when does the bouyancy characteristics of the each tank change? at around what pressure left in the tank do they change and how they change?

do a test and you will be amazed by what the charts read. I have personally experienced/handled/dove/filled and tested all the 3 above mentioned tanks before i wrote what i wrote and did the neccessary research to back up what i said.

i believe what i see for myself and "tests" that i did, because i was wondering about the advantages/disadvantages cause i liked the light weight of the HP initially when i was first introduced to them. however, the weight and size to me was insufficient to make up for the difference, espicially after discovering the actual rating of the faber LP steel tanks

my notes were based on all that, not only facts and figures from DOT ratings

erm... one more thing, not many many of the steel tanks over 30 years ago are still in service, reason being manufacturers thought that by internally coating the tank would reduce corrision and make the tank last longer, but now, they change their mind, and so, many many of them are actually retired due to the paint.

 

[CompuDude]

erm... one more thing, not many many of the steel tanks over 30 years ago are still in service, reason being manufacturers thought that by internally coating the tank would reduce corrision and make the tank last longer, but now, they change their mind, and so, many many of them are actually retired due to the paint.

No point in continuing the rest of the discussion, as without the ability to cite sources, there's not much point.

Re this, though. See how much your aluminum 80 or 100 is worth after 10 years. Now see how much your steel tank is worth. (Assuming both have been reasonably well maintained)

I like my HP steel, and I'm happy with how much gas they hold, how much they weigh, their size, etc. I do heartily recommend trying out (borrowing, probably, since it can be hard to find steel to rent) each tank in question before buying, and running the numbers to see how much gas you'll have in each scenario, before buying.

(And I do recommend buying)

'Nuff said, this hijack ends here...

 

[Aaagogo]

agreed,

erm... manufacturers won't say anything bad about what they did, like the AL tanks before 1990...

nope, i don't own anything other than 4 LP108, 1 LP 45 and an AL40 but i have access to tanks of all shapes/sizes/capacities/makes/models....

however, there's only 1 hp tank that i will join u on that, a hp steel 80 that is shorter than an AL62 and extremely light