Purchasing Doubles

[BlowBubbles]

Next year I looking to purchase my first set of doubles. I'm 6'-3" and 240'ish. I know I want steel cylinders. I would like input on what size cylinders and high or low pressure. I know depth and dive duration is of prime concern. I want them starting intro to tech, and eventually deeper trimix dives.

[CaptnJack]

hp100s, the universal starter doubles.
Yes at your size you could go bigger. But for your first few years of deco diving you won't be doing dives which need more than 200cf of gas anyway. If you eventually choose to go onto even deeper diving you'll also end up with multiple sets of doubles as well, or who knows a CCR. And if you decide deco diving is not for you, the 100s make great singles too.

[Geek]

I would go with 119's, also excellent singles and only about $50 more for the set...

[lamont]

if you're buying new, probably worthington X7-100s like richard said. i've found those tanks a little easier to trim out than other hp100s that i've tried (which are typically lighter, and more butt-light).

faber LP85s might be better tanks for you since they're nice and long and will fit your height even better.

if you must go big tanks, get the X8-130s or similar lp104/hp130 sized tanks, lp95s/hp119s are shorter and don't weigh that much less, and you're plenty big and tall enough for the 104/130s...

[LCF]

Where are you going to be doing this diving? That makes a difference. If you are diving in Asia, you'll probably want Al80s -- they work great in warm water with minimal exposure protection. The same might be true if you are diving inland fresh water sites. (I can't tell, from Boise and Joseph, OR, where you might be likely to be diving.) If you're diving our cold salt water, then I'd agree with Richard. HP100s are adequate gas for dives in the 150 range. They're not unmanageably heavy. They have good resale value. And we have no issues, at least in the Seattle area, with getting adequate HP fills.

At your size, you can almost certainly manage bigger tanks. But I'll tell you the experience of my #1 dive buddy -- he's strong as an ox, and started with HP130s. After a couple of years, he bought a set of LP72s for his son. He started diving them from time to time, and one day he looked at me and said, "I now ask myself WHY I hauled those big, heavy tanks around for so long, when I didn't really need them."

If you really get into tech diving, you'll end up owning multiple sets of doubles, so you may as well start with a set that's comparatively comfortable, and if you move into deeper dives where you need more gas, you can buy another set.

[lamont]

Lynne, I also had an experience diving double-130s with a newbie diver at redondo where we got rolled around by containership wake enough to really incapacitate me, and that led me to rethink how silly the 130s are and start looking for smaller doubles.

I don't like LP72s, though, since they're waaaaay too butt light for me, same thing with AL80s, i can't trim those out short of wearing a weightbelt (which helps me on my frame, since the weightbelt rides down at or below the bottom of the tanks).

[CaptnJack]

130s are enough for 2 entry-ish level 150ft deco dives for me, like the Bomber, Harpoon, Urania, Waterman's, Dalco etc. Why carry gas for 2 dives when you don't need it? You're just even more likely to end up with 1/2 full tanks with the wrong mix in them.

I have dove hp130s, lp104s, lp108s, hp100s, lp95s, hp119s, lp85s, al80s, lp72s you can find all of these locally some more easily than others.

In order for Puget Sound, cold water drysuit 130-160ft dives, I would suggest:

hp100s work great all around, good to 180ft ish.
lp85s if your shop will do 3000+ fills in them
lp95s if your shop will do 3000+ fills, not too bad with only a 2640 fill just a bit of a waste.
hp119s (heavy)
hp130s (heavy)
lp104s (heavy, not made anymore)
lp108s (heavy yet buoyant!)
lp72s (not enough gas)
al80s (too much lead, not enough gas)

The others may work but as noted they are expensive, big and heavier. You only have one set of vertebrae and the less wear and tear you put on them the better.

[BlowBubbles]

I used to have double A-80's. I split them up because I hated the buoyancy and trim characteristics. I'm leaning toward steel 100's, 119's or 120's. I don't know if I should get LP or HP.

[Mattleycrue76]

Another vote for hp100s. If you still have the bands from your 80s you could probably reuse them.

[CaptnJack]

I used to have double A-80's. I split them up because I hated the buoyancy and trim characteristics. I'm leaning toward steel 100's, 119's or 120's. I don't know if I should get LP or HP.

As Mattley said, use the bands from the al80s for the hp100s.

The 119s would be ok but will require new bands. The 120s might be ok given your height, they will work with your old bands. The big "nit" with 120s is that anyone smaller than ~6ft or so finds them too long. So resale value is fairly weak on 120s.

All of those sizes are "hp" 3442 psi sizes. In lp terms the hp100s = worthington lp85s dimensionally. faber lp85s are narrower. hp119s = lp95s dimensionally. hp120s don't equal anything in lp terms dimensionally.

[LCF]

95s are beasts. They're heavy and they balance horribly. I don't like them at all; they're even worse than the despised 72s in my book.

Al80's, for me, balance real well in fresh water with 7 lbs on the bottom bolt (half of a 14lb v-weight). In the Red Sea, I had 2 kg hanging from the bottom bolt, and 6kg more on a belt (diving dry) and they balanced beautifully. The nice thing about them is that, because they do require weight, you can put it where it works for you. More negative tanks may not give you any option but to learn to balance them as they come.

I love my Worthington 85s, but the Fabers require more weight and are tail-light when empty. I found that out the hard way . . . Nothing like doing a staged decompression dive with someone who has never seen you in the water before, and spending your 20 foot stop swimming around head-down to stay underwater!

[sea2summit]

I think bigger is always better until:
1) you have to carry them anywhere.
2) you're diving off a small boat.
3) you miss a dive that required a very spcific mix and now you have to decide if you're going to blow $250 on a 60' dive with buddies or buy a new set of doubles.

Beyond that 95's with a "cave fill" will get pretty much anything done.

[Joshua Smith]

I think bigger is always better until:
1) you have to carry them anywhere.
2) you're diving off a small boat.
3) you miss a dive that required a very spcific mix and now you have to decide if you're going to blow $250 on a 60' dive with buddies or buy a new set of doubles.

Beyond that 95's with a "cave fill" will get pretty much anything done.

Can I get an "Amen?" my OC tech diving buddies have dozens of sets of doubles with mixes for fairly specific dives that didn't work out for one reason or another. they set them aside until the next 230-280-310 foot dive comes up......and lugging 2x130s around ain't fun. I like to get paid for working that hard.

[fishb0y]

95s are beasts. They're heavy and they balance horribly. I don't like them at all; they're even worse than the despised 72s in my book.

I dove with 95s for a couple of years... I thought the balance was fine but heavy is an understatement! Now I'm diving double 23's... my last fill (21/35) was a steep $10.50

[CaptnJack]

95s/119s are actually "midsize" IMHO. But still not really necessary for beginning deco diving in the 120-160ft range or therabouts.

[BlowBubbles]

I love the input,this is a great site.

With doubles I will diving Puget Sound or in local lakes when I can't get away. When in Asia or Hawaii I will rent tanks.

I once did a wall dive with a rented Heiser 120 without knowing the caracteristics. That tank was the heaviest thing I ever dove. In a wetsuit I dumped my air and sank like a stone. Scary till my BC caught me at 150. Ascended without and problems but went out and bought a huge wing. Anyone interested in purchasing a red banded OMS 94 lbs I don't use it anymore.

[sea2summit]

...went out and bought a huge wing. Anyone interested in purchasing a red banded OMS 94 lbs I don't use it anymore.

Your saying a 94# wing is too small? What is your build I've never dove over a 60# wing and that was never full except when I was at the surface feeling lazy.

[BlowBubbles]

On the fore mentioned wall dive I was diving my first wing, a small no name knock off. I was so freaked out by not being able to slow my descent I bought the way to large wing. I wish I had a sight like this before purchasing the wing.

[CaptnJack]

On the fore mentioned wall dive I was diving my first wing, a small no name knock off. I was so freaked out by not being able to slow my descent I bought the way to large wing. I wish I had a sight like this before purchasing the wing.

Yeah the heiser's are serious beasts. I don't really understand why someone would buy one??? Especially new?
(you rented, didn't know, etc etc)

You could probably sell the wing on Ebay in a week. Locally I don't know anyone who would buy it, I use a 55lb wing with doubles and multiple stages just fine.

[ArcticDiver]

One of the privileges of sitting on the beach, temporarily I hope, is having time to observe from a distance and reminisce a bit. With that as a background if I were you I'd take a good double thought about what I bought. I learned doubles with 120's at the same time I was exploring cave diving. I could handle them. But what a load!f I did quite a bit with HP100s. I own double AL80s, which are very good for fresh water. When I travel I often twin up AL80s. Properly used the AL80 is a very versatile and useful cylinder.

All that said if I were starting out today I would skip the doubles all together. I'd rent until I could get squared away with a rebreather. That is the way of the future for people who want to do extended range diving. Plus, more and more tourist destinations are carrying consumables for rebreathers. From what I was shown a short time ago total costs for a diver starting out aren't much different than going for the stable full of cylinders the OC diver has.

Just a thought.


By the way I have a double bladder OMS wing I bought after a similar incident and because a "friend" wanted me in a project that has never been wet and I'll never use.

.

[sea2summit]

All that said if I were starting out today I would skip the doubles all together. I'd rent until I could get squared away with a rebreather. That is the way of the future for people who want to do extended range diving. Plus, more and more tourist destinations are carrying consumables for rebreathers. From what I was shown a short time ago total costs for a diver starting out aren't much different than going for the stable full of cylinders the OC diver has.

Just a thought.

I try and provide constructive input in threads like these but seas you started it....X2

For the cost of going tech you will be very close to a CCR. Don't know how much diving you do or what kind but my fill for this whole weekend of diving 10/60 cost me $10.55 when I picked my tanks up today.

[fishb0y]

All that said if I were starting out today I would skip the doubles all together. I'd rent until I could get squared away with a rebreather. That is the way of the future for people who want to do extended range diving. Plus, more and more tourist destinations are carrying consumables for rebreathers. From what I was shown a short time ago total costs for a diver starting out aren't much different than going for the stable full of cylinders the OC diver has.

Since I moved here from Hawaii, I stopped doing deco/deep dives due to the prohibitive cost of He and the multiple sets of doubles it requires. I decided that the best path for me was to save up for the unit/training instead of blowing money into the water. Now that I have a CCR I have no reservations on getting back into tec diving...

[ArcticDiver]

BlowBubbles:

What is the status on your quest? Curious minds, both of mine, want to know

[BlowBubbles]

I'm on my way to Singapore for a couple months. After all the inputs I'm leaning toward the X7-100's. But we'll see next summer.

[ArcticDiver]

Sounds like we have something in common. Neverr in any hurry to spend money.

Have fun in Singapore.