I love doubles

[dsteding]

Did my first dive with Bob (Grateful Diver, but you all know that) in doubles.

I borrowed his whole rig, a Halcyon wing, and double 119s. We planned on a nice mellow dive at Cove 2, and ended up spending a bit of time around the Honey Bear.

Impressions:

These things give you a really, really stable platform. I love the way they dive. My trim and buoyancy was far from perfect, but I can see how these things give you a great platform to work with (I was swimming in small circles at the safety stop, but that may have been me being nervous about holding the shallow stop).

Wow, if your kicks are crappy like mine are, doubles really expose those flaws. I need to work on my frog kick in particular, and I'm actually kind of happy that doubles exposed that-it is something that can be remedied fairly easily.

There is A LOT of gas in those things. I started the dive at 1400 psi and ended it at 500, which just seemed weird to me after diving singles. Full doubles is certainly a lot of gas . . . .

With the harness and plate, I was actually a bit surprised regarding moving around on land. It is not like they were light (close to 100 pounds isn't light) but the harness and plate make things solid enough that you can more around reasonably well. I'm not planning on running a 5k in them, and stairs wouldn't be fun, but they are manageable.

One question to those that dive doubles:

1) Tanks. I was diving double 119s, I have as possible doubles candidates two Faber 98s, or I can buy one more Worthington 119 or 130 and double it up with the one that I already have (I have one 130 and one 119). I'm thinking either the 119s (I liked the way these trimmed out) or the 130s) . Lamont, I think you have both, any preference between the two?

Another question to anyone else:

Does anyone have a used 6 cu aluminum tank? The whole argon thing was really nice tonight.

Thanks again to Bob for sharing his rig, it was a great experience.

[Sounder]

Sounds great... but enquiring minds want to know - was GD on a single the whole time matching psi for psi with you?! He can stay down on a LP95 for a week! I too look forward to exploring the realm of doubles in about a year or so.

For what it's worth (realize that I've never dived doubles and don't know much about them), many guys I've talked to including Geoff C. a.k.a. "Bones" (on of Lamont's dive buddies) who I've talk to a lot recommend double 130's. Other's in the same croud sport double 104's. This concludes my knowledge on doubles.

Excellent report on your first experience... funny how slight changes expose our bad habits.... I'm sure mine will be clearly evident when I hit the water again. Keep us posted on what you decide!

I'm also now in the market for one (maybe two) 6cu and/or 14cu argon bottles. Fortunately, they're not high on the scuba unit scale... I like the Techdiverslimited.com rig and the Salvo.com 1st stage. I'll be "diving" into them soon for my better half.

[dsteding]

Sounds great... but enquiring minds want to know - was GD on a single the whole time matching psi for psi with you?! He can stay down on a LP95 for a week! I too look forward to exploring the realm of doubles in about a year or so.

Well, I just calculated my RMV, it was up around 0.9, maybe a bit less, so I'm sure Bob was matching me psi for psi.

For what it's worth (realize that I've never dived doubles and don't know much about them), many guys I've talked to including Geoff C. a.k.a. "Bones" (on of Lamont's dive buddies) who I've talk to a lot recommend double 130's. Other's in the same croud sport double 104's. This concludes my knowledge on doubles.

Yeah, my only concern is that 130s will make me trim out a bit more butt-down, but they trim out about the same as singles. I'm hoping Lamont chimes in here (or others that have/dive both 119s an 130s)

Excellent report on your first experience... funny how slight changes expose our bad habits.... I'm sure mine will be clearly evident when I hit the water again. Keep us posted on what you decide!

Thanks, and so true about the slight changes . . . this was a great example of that.

I'm also now in the market for one (maybe two) 6cu and/or 14cu argon bottles. Fortunately, they're not high on the scuba unit scale... I like the Techdiverslimited.com rig and the Salvo.com 1st stage. I'll be "diving" into them soon for my better half.

This whole thing is going to cost me so many scuba units that the argon bottle becomes kinda inconsequential as compared to regs, tanks, wings, plates. I may buy it now and just get all the pain over with . . .

[lamont]

1) Tanks. I was diving double 119s, I have as possible doubles candidates two Faber 98s, or I can buy one more Worthington 119 or 130 and double it up with the one that I already have (I have one 130 and one 119). I'm thinking either the 119s (I liked the way these trimmed out) or the 130s) . Lamont, I think you have both, any preference between the two?

I don't understand why, but I've found (and those older and more experienced than me have confirmed) that the HP119s/LP95s are a little twitchy from side-to-side. My X8-119s were also about 2# more negative than my E8-130s each, which added another 4# on the tanks, and I usually put 20# of nitrox in them (keeping my double-130s as trimix) which made for floating very low in the water when they were full.

To keep things simple I just broke down the 119s the other night and turned them into my single tanks and doubled up my other 130s. Having completely standardized tanks among the entire team also helps with gas matching when diving thirds. My big reason though was the buoyancy shift between my double-130s and my double-119s and its much easier for me to just standardize my own diving on double-130s because I have four 130 tanks to turn into matched sets.

I also found no real difference hauling around the 119s and the 130s. I'd go 130s, and if you want smaller doubles get HP100s/LP80/LP85s or Al80s.

YMMV.

[Scubak]

I know a lot of people that dive the 104s but then there are a whole group of people that are diving the 130s...it makes it simpler for gas management and dive planning if you can match your buddies tanks...ie. everyone is diving the same tank size.
I dive a set of twin HP 80s, for me they are the set...if I could I would get a set of 100s...
As for Argon,,,went there years ago and never went back. Even in the summer I use it as part of my ditchable weight and fill with just air. Hope this helps.
K

[dsteding]

Thanks ScubaK and Lamont-

As to the 119/130 question, do you find any difference in feet/down feet up trim? Reason I ask is that my 98s are sweet single tanks for me (very top heavy) and I shift a bit of weight around to accomplish the same balance with a 119 or 130.

Bob's PST 119s trimmed out well, I think any issues in terms of trim were mine and not the rig. Given that the difference is only a pound of buoyancy and 1.5 inches in length, I imagine the 130 would trim out similarly, they do for me as single tanks.

If the 130s balance the same, I may go with those. I wouldn't need a 130 single anymore, because the dives I used that tank on would be covered by my doubles.

[CaptnJack]

A couple of inches in length really can significantly alter your trim IMO.

I don't totally understand the need for 260cf of gas, but that's neither here nor there. My hp100s are good for just about any reasonable Tech1 dive. If I need more than 200 cf of bottom gas, I'm bringing an AL80 stage - a more versatile combo.

Last weekend I used 18/45 in the doubles and 50% in my 40cf bottle for dive 1. Then I switched the deco bottle for a bottom stage of 30/30 and did a second NDL dive with the backgas (which I never touched) serving as rock bottom.

I also have lp85s and they are nicer than the hp100s, longer length trims out better for me.

Be careful of your backs hauling all that weight around.

Richard

[dsteding]

CaptnJack-

I agree, a couple inches can affect my trim, I also agree that 260 is a ton of backgas . . .

What I may do is get my rig together, and try a friend's 95s. For me, the 119s trimmed out well, I'm going to try the 95s, see how they trim out-even though the tanks are the same size, I've seen significant trim differences between my 98s and my 119 (not surprising given they are built differently-my 98s are much more top heavy, the 119 seems to have more weight in the bottom). I may then even double up the 98s with a 300 bar manifold so I could switch to 119s if I wanted to. I love my 98s as singles, probably my favorite single tank from a trim standpoint.

Biggest drawback on the 98s is they go neutral when empty, so I'd have to carry some additional weight, the 119s were just about perfect with a 9 pound plate.

[Diver_C]

I find, once in the water, not much difference between my single 100s, and my double 100s. It makes it very easy to switch back and forth. I do use two different, but similar wings depending upon doubles or singles. Both are Halcyon donut wings, Eclipse and Evolve. [Mmm... donuts...] The only real difference bewteen the two is width.

I find taking pictures of the things on the bottom or on a wall usually easier if I'm upside down. Initially, it was a little screwy with doubles, but once I got my back plate better adjusted, nearly just as easy to hang upside down with doubles as it is with singles.

I think switching between doubles and singles is easy because I'm using similar wings, and cylinders. I am not a tall person. I cannot imagine using cylinders bigger than the my hp 100s. Not sure my back can either. I think doubles are great for long dives, otherwise I'll use my singles.

[CaptnJack]

Sounds like a good plan. BTW you don't necessarily need 300 bar manifold and I'd actually suggest getting 200 bar.

Those are just slang terms, "200 bar" is totally adequate for 3442 psi HP cylinders. 300 bar valves can sometimes get dinged and the DIN fitting won't seal good when the threads and face are out of alignment. The old starfish had an O2 analyzer which never sealed well on my 300 bar manifold although it was fine for everything else.

here's some good info on 200 vs 300 bar valves.
http://www.diveriteexpress.com/library/ ... tml#dinfaq

Richard

[dsteding]

Sounds like a good plan. BTW you don't necessarily need 300 bar manifold and I'd actually suggest getting 200 bar.

Those are just slang terms, "200 bar" is totally adequate for 3442 psi HP cylinders. 300 bar valves can sometimes get dinged and the DIN fitting won't seal good when the threads and face are out of alignment. The old starfish had an O2 analyzer which never sealed well on my 300 bar manifold although it was fine for everything else.

here's some good info on 200 vs 300 bar valves.
http://www.diveriteexpress.com/library/ ... tml#dinfaq

Richard

Thanks for reminding me of that-I forgot my HP tanks have 200 bar valves, my LPs, ironically enough, have 300.

I don't like the 300s because of the deeper threads-and I've heard about them getting dinged.

[lamont]

Sounds like a good plan. BTW you don't necessarily need 300 bar manifold and I'd actually suggest getting 200 bar.

I've got a 200 bar manifold that has been to 320 fsw several times and lived to tell about it...