Choosing Tanks

[Blue Sparkle]

Nobody has touched on my question about finding DIN vs Yoke and steel vs aluminum while traveling (any where we have to fly).

I can give you a perspective from the Florida Keys.

Most of the rental tanks I have seen there are aluminum, with yoke valves. Usually AL80's, with AL63's commonly available if you ask. For deeper dives I've seen AL80's, AL100's and (steel) LP95's.

Because I knew I would be diving primarily in Florida, with rental tanks, I got regs with a yoke fitting. As a result, I have not noticed if any of the tank valves were convertible. I suspect most were simply yoke (perhaps with the exception of the LP95's?).

I think the yoke vs. DIN on tank rentals may be a regional/country thing.

As far as weighting and re-figuring it for each tank when you travel. I'm guessing that the tanks will not be as much of a factor as will going from cold water and lots of exposure protection to warm water and little or no exposure protection.

I'll give you an example of how I have done it in warm water: I did a proper, dedicated weight check on my first Keys trip where I had my own BC (rented a tank and went to a place I could "dive" right next to a wall where I could set extra weights). After that, I was able to calculate from that base, and be close enough - with a change in exposure protection or tank - to have a fine dive with maybe a tiny tweak for the second dive/future. For example, my weight check was with an AL80 and no exposure protection. When I later switched to AL63's, I looked up the tank specs (I printed and laminated a copy for my dive log so I have it on hand) and could calculate the difference.

When I later added a 3mm suit, I went with an estimate I found (add around 2# per mm thickness), started with that, and then kept tabs on how it felt at the end of the dive with a light tank. I always keep detailed notes of what I wear in terms of weight and exposure protection + tank, and how it worked out, to refer to. I find them really useful.

Then I dived with an LP95 (steel) and the 3mm. Same thing - I looked up the tank specs and calculated. I did make a trim adjustment as well because the AL tanks are a bit more "butt light" on me than the steel is. But again, I took notes and so now it's part of my record I can refer back to. Not that there is anything wrong with another "formal" weight check either.

I imagine that it varies more in cold water, and so maybe my methods would not hold true there; but I figured this might help you from a warm-water, place-I-might-go-on-a-diving-holiday perspective.

On the DIN reg with a yoke adapter. As was earlier mentioned, that add "depth" and the reg will protrude further toward your head/neck. This may or may not be a problem for you. On me it would be uncomfortable and I would not like to dive that way. That's one reason I bought yoke regs (I knew I would be diving with yoke-valved tanks for the near future and they can be internally converted if I end up diving DIN). Right now the HOG regs are DIN only (otherwise I would have bought them in 2010), but they have just announced their intention to bring a yoke conversion (internal, not an adapter) to market.

Blue Sparkle

 

[danvolker]

After seeing TS&M's post, I noticed you were from Wa....When we ( in Florida) switch to drysuits for Jan-Mar, we change our tune allot, and suddenly we like hp 100's and the weighting.....and here, the al 80 would be really horrible!

 

[Blue Sparkle]

When we ( in Florida) switch to drysuits for Jan-Mar, we change our tune allot, and suddenly we like hp 100's and the weighting.....and here, the al 80 would be really horrible!

Just to clarify my previous post (in case it sounded like I was speaking for all of Florida or all divers there), I was just referring to what I have seen in the Keys as a beginner/recreational/wetsuit/tank-renting diver (I noticed the OP said he and his buddy will not have drysuits for the near future).

The diving does sound really interesting around Palm Beach, and I hope to dive there at some point (probably in "wetsuit season" though as I don't have a drysuit). Along that line, would the typical rental-tank/wetsuit/recreational boat dive provide steel or aluminum tanks? Would they have yoke or DIN valves?

Thanks,
Blue Sparkle

 

[danvolker]

Just to clarify my previous post (in case it sounded like I was speaking for all of Florida or all divers there), I was just referring to what I have seen in the Keys as a beginner/recreational/wetsuit/tank-renting diver (I noticed the OP said he and his buddy will not have drysuits for the near future).

The diving does sound really interesting around Palm Beach, and I hope to dive there at some point (probably in "wetsuit season" though as I don't have a drysuit). Along that line, would the typical rental-tank/wetsuit/recreational boat dive provide steel or aluminum tanks? Would they have yoke or DIN valves?

Thanks,
Blue Sparkle

Most boats in Palm Beach rent out al 80's still, though some boats do have several steel 100's or larger.....Yokes are the norm, DIN valves can be dealt with by the boats, as most have adapters, but the dive operations have seen no reason to consider DIN valves whatsoever. The 80's are likely to remain, because of the large investment in inventory most boats already have.....there will gradually be more and more larger steels going in to their inventories though.

 

[Hatul]

For shore diving here in S Cal less than 60 ft deep I prefer the HP80. It's about 6 lbs lighter to carry to the beach than the HP100 and it feels more agile and easier to trim under water. For deeper dives the extra air of the HP100 sways the argument to the larger tank, and also most deeper dives are from a boat where the weight is less of an issue.

The ideal for local diving in S Cal is two HP80 and one HP100. I have two HP100's and I'd be glad to swap with someone for an HP80.

One other thing, when buying a tank, it's nice to get one with the safety indicator valve that tells you at a glance if the valve is fully open.

Adam

 

[Jax]

Nobody has touched on my question about finding DIN vs Yoke and steel vs aluminum while traveling (any where we have to fly).

I have to disagree with the people saying DIN isn't available.

I was in Coz in November, and they had quite a few convertible (screw in an insert for yoke) valves on the AL80s.

As repairs and replacements occur, a lot of people seem to be going to the convertibles.

 

[Darnold9999]

Depends were you go. tourist diving aimed at the US market will be yoke possibly/probably DIN adapters available anywhere else will be yoke and DIN will be available. I have only seen DIN - with yoke adapters in a couple of places.

 

[NAM001]

So far this has been the most confusing part for me. There are Steel and Aluminum then .....
I know there is a lot of questions in there and thanks for you time.

Let me tell you what i did when i bought my tanks. which case i bought faber lp95. i have lp85's and a lp120 also. i started doing a lot of readig on tanks. steel cost more than al but it is a one time buy so that is moot. in 2003 there was a lot of articles on how fla was raping the tourests for air fills. the reports said that the shops would not fill unless they had that shop vis sticker,,, or no eddie test no fill. you were now forced to rent thier tanks. the times i have dove in fla i have never witnessed anything like that. the history of al tanks cracking (sustained load cracking) unreasonable inspectin requirements all centered around the use of al tanks. next was the issue of getting a full fill. i know the local shop compressor auto shut downs at 3200#, shops well say 90% or better fill is a full fill. the lp's were fullat 2640 with the +10% and 2400 with out it. souunds like what you used. the bouyancy was more neg than al's. for those who engaged in overfilling. (cave fills) you got yet another 10% fill on a lp tank. my lp95 holds about 108 at 3000#. (i am not advising that practice.) the al80's were not 80 they were something around 77's. the steel after the first hydro if not done with the + rating. you lost 10% of the fill volumn so the lp 95 at 2640 is now a lp85 at 2400. still more than the al 80. no one questions (in fla shops i used) a steel tank when it walks into a shop for a fill. most shops asked how much do you want. refering to how much overfill do i want. some one mentioned you are the envy of the shore with steel tanks. that is somewhat true. because most tanks are al. thats what the shops rent. even the ocean shops. so that trip to coz will be a diving trip using al tanks. i carry 4-6# less led when i use steel.]

now the question. which should you get???? do you use no lead when you dive al in fw. steel not for you. if you dive with lots of lead in fw get steel. if youare going to dive in salt water get steel. if you are going to venture into dry suit diving get steel. you will need the weight to keep the suit down. the lead you carry is not just a weight issue, it is a weight placement issue. if you use an al tank and you are carying 15# on a belt at your waist. you will be , generally speeking ) head ight and but heavy. since your body moment is in your chest and not your waist. the steel allows you to dicipate the weight feom head to waist, thus the center of weight is at the center of body mass, that is a good thing. now transition from fw to sw is anywhere from 1# for every 40 body weight to maybe 1 in 25. i am 1 in 30 my self. i seam to be protecting the romping stomping muscle bound body of mine with a THIN pretective layer of lard. in general higher body fat the more weight you need to comp for sea water. i suppose you can ask for steel tanks when you rent but the al's are so common in rentals. fla probably would have a higher chance of finding steel rentals. costs of tanks as sax player has said is on the money it is sound advice. a steel tank will last for decades 60's and 70's tanks are still widely in servince. not so true for the al's. many start showing the cracked thresds thingy (sustained load cracking) and are condemned.

yolk or din...... i have combo valves. put in the tank insert and it is a yolk valve. get the tank with combo valves. 2 reasons. 1 you can convert to swing either din or yolk. a shop that only as yolk fill whips can fill with the yolk plug in or with an adaptor. 2. when you get the combo valve it is a combo yolk and 200 bar din valve. not the 300 bar din valve. 300's are not made in a combo. there is no aluded higher strength factor in the 300 over the 200. same max pressure. the difference is the depth of the threads in the valve. the difference is to accomodate the regulatorsince it has no blow out plug on it. the 300 has more threads to it the 200 has less. you can not put a 200 bar din reg on a 300 bar valve. it will not seal. you can do the opposite and put a long thread 300 into a shallow,less thread 200din valve. you need to understad that. i have not seen a din reg that does not have a 300 din on it. a low presure reg that cannt handle the psi of 300 bar wil have a 200 bar thread on it to insure you dont put it ion a 300 bar tank. so 200 bar combo tank valve. btw 300 bar is 4500 psi. steel is more prone to corosion than al. both corrode, understand that. those who tell you al dont rust is a partial truth. rust is the product of oxidized steel al also corrodes and has its own byproduct. it is a black of dark gray substance.

i have no advise on whether to use lp or hp as jorgy spoke of.. as size goes i prefer my lp120. without the 10% overfill rating at first hydro it is now about a 108 at 2400 psi and if some one overfills it thinking it is an al tank you have 140 or so. that is a lot of air. up side one tank lasts forever. down side some shops charge a single fill for an 80 and above that double fill charge. because an 80 minus the reserve at say 500# is only a maybe 60 cu ft tank so a 120 is same as 2 tanks and gets charged as if it were 2 tanks. if you have your own compressor it is easier to fill to 2500 than it is to 3500. a shop with the compressor down can still get you a full fill of 2500 when they cant fill thier banks to 3000 for the al users or 3500 for the hp steels. if you fly to your dive spots you wont be taking your tanks, tank weight , new vis required, hasmat issues make it prohivitive. so you will rent. given that ..you may want al's so you will have tanks you are familiar with. btw an al100 is a nice tank with bouyancy similar to the st lp95's but is still an al tnk subject to cracking issues. if you dont use much air perhaps an lp85 will be your thing. the lp85 is about a 32# tank, same as teh hp100 mentioned in another post. btw a hp100 filled to 3000# is about 85-90 cu ft . it is very comprable to the al tank weight. great pro if you have to carry your rig any distance to water entry point. as far as adaptors.. the ones i mentioned earlier were filling purposes and not for regulator adaptation. the last reason i got steel was that they hold more than teh al 80. my concern was at my age that if my sac was not as good as the younger buddies i did not want to cut thier dive short because of gas availablility on my part. my sac is avg .5 so i dont need the extra air for that but it is nice to know i have air to share ifneeded at the end of a dive. i often get 2 dives on my 120 when the buddies ahve to change tanks for the socond dive.

well that is a lot of info i know but only the surface of what is available here on the board.

 

[tbone1004]

I was only mentioning the LP tanks because it's what was available in craigslist in his relatively local area at the time.
I dive LP72's, HP100's, HP120's, and lp112's. 72's are doubles and sidemount, 100's are sidemount, 120's are sidemount and 112's are doubles. I prefer the 72's, but if I need the weight for the drysuit, the 100's come out, and yes, they really are the best tank out there for most applications.
What I would recommend is getting what is cheap and available in the area, and that way you're set for now, and steel tanks don't lose value hardly ever. All of my 72's are at the youngest 50 years old right now, and they all got their + rating or got it back this year. A few didn't get them for whatever reason on their second hydro, but passed now. I have seen/heard of this happening a lot. My 112's didn't get it on their second hydro and on this one they did *the dive shops were the ones that sent out for hydro when they didn't get it and I brought it to the hydro place and they asked if I wanted them back on there. I said hell yes so long as they pass*.
When they are talking about good fills, it's a wonky subject. The compressors will almost always be able to pump to at least 4000psi. The banks may not be able to be pushed that high, and if the tanks are particularly empty, then the tanks will get really hot when they're filled and when they cool off they will drop pressure. The old PST tanks are the worst IMHO with this. The regulator from the fill stations may also only be set at 3000 or 3200 psi, so it's rarely the compressor, and if you're filling directly off of it, make sure to fill a couple hundred psi high and it will fall back, or fill to working pressure wait a couple hours for it to cool off then top it off which is ideal. Most shops won't do this because it's extra time or they'll charge you extra for it. LP's are a bit nicer in that respect. I don't care if I have good fills usually because I'm carrying a lot of extra gas, but some people gripe.

I have seen 200bar regs, but they were all argon regs :-D. 200 or 300 bar din doesn't matter, but you'll read about that.
SCUBA Valves, Regulator Fittings, and Cylinder Neck Threads - Dive Gear Express
Read that, explains all. Basically, find what you can find cheap. I have never had a tank fail hydro, but if you're worried make sure that you get a written agreement with the dude selling for a refund if they fail hydro. Most sellers will do that, but are just too lazy to get it hydro'd before. Avoid the diveshops for any tank maintenance if you can because they will rape you. Most of the time someone in a dive club has a VSI certification to do vips usually for the cost of the beer that he'll drink while vipping them. That's what we do around here at least

 

[halocline]

Nobody has touched on my question about finding DIN vs Yoke and steel vs aluminum while traveling (any where we have to fly).

Forgive me if someone else already posted about this, I haven't read the entire thread.

Since you have DIN regs, buy DIN tanks. Unfortunately this might cost you a little more in valves, because the best thing for you to do is to buy used tanks. Honestly I would go cheap on the tanks, buy 4 used AL80s unless you can get a deal on used HP100s (the SP tanks by either faber or worthington or PST, NOT the older 3500 PSI tanks). The used AL80s will probably come with a yoke-only valve, so at some point, maybe the first inspection, you can change the valves to DIN. Until then just use your adapters if you have to.

The reasons I would emphasize buying used tanks are: 1) If you're in cold water and you really want to dive regularly, you're going to buy drysuits....and I think you have to make that somewhat of a priority. Those are a lot tougher to find deals on than tanks. 2) Used tanks are every bit as good as new tanks unless they've been abused and will not pass inspection, in which case they're worthless.

With steel tanks, there is a chance that the interior is rusted from abuse. This usually comes from a bad air compressor that puts wet air into the tank. These days, most dive shops (I think!) maintain their compressors fairly well, but it still means that you have to inspect steel tanks BEFORE you buy them. It's not rocket science, just look inside with a light that drops in the tank and a small mirror, but if you can't do that at this point, you're taking a chance on used steels. AL tanks do not rust, and while some corrosion can develop on the interior of the tank, they're much less of a problem in this regard and can almost always get cleaned easily. So, buying used AL80s is not only cheaper, but less of a risk. Just don't buy anything older than say, 1995 (some chops simply will not fill older AL tanks, even though there's no reason) and you should be fine getting fills almost anywhere.

There's no question that in cold water, steel tanks are nicer to dive with, and everyone has a favorite. But unless you're made of money, you have to weigh the benefits vs cost vs time, and figure out what will solve your current problem in the best way. For me, if I were diving in very cold water, I'd go hungry until I could afford a drysuit.

Another issue is that there is no "best" tank, because your needs change with each dive. You might start 'collecting' tanks; eventually ending up with some small light tanks for shallow shore dives and a few larger tanks for longer dives. Don't worry too much about bottom time at this point though; you're new divers and without the dry suits you'll probably be freezing after a while anyway.

For travel by air you never take tanks, unless you're on a private plane in which case you probably don't need to save any money, and you can just run right out and get four new worthington HP100s