Doubles Recommedation - New Tanks

[The Kraken]

I would like to request, from those of you experienced with doubles, what you would recommend based on the following parameters:

1: New Tanks
2: Mixed gas
3: Use: Recreational, wreck penetration, max depth 187 FSW
4: Physical size - 5'7" 160# avg SAC .39

I've come to the point wherein I've enlisted training to advance into a higher level of diving and would like some knowledgeable input. It's seems to be a bit difficult to get objective input from the LDS's. I'm sure $$$ has something to do with it.

If you choose to respond, please use the parameters set forth to make your recommendation.

Thanx . . .

Safe dives . . .
. . . safer ascents!!!

 

[jonnythan]

Hey, you're my size. I'm still wrestling with the 130s/119s issue at the moment. I'd love to try both out then decide, but that doesn't seem likely. Guys I dive with have insisted on the 130s, but I like the idea of shorter tanks..

 

[simbrooks]

1: New Tanks
2: Mixed gas
3: Use: Recreational, wreck penetration, max depth 187 FSW
4: Physical size - 5'7" 160# avg SAC .39

Some further questions
1: So you arent looking at the healthy secondhand market?
2: Are you talking of the HP vs mixed gas debate? Not meaning to start that up, just wondering if that is why you put it here. Are you looking at a trimix course?
3: Why 187fsw? Is it a PPO2 thing or is that the deepest wreck in your area or something else? That isnt a rec depth, are you thinking adv nitrox deco soon?

Now my thoughts:
1: We all know PST are hard to find new at the moment, long wait, unless you know the place to find them, OMS/Fabers are more readily available.
2: See above, not sure this makes a difference, but i could be wrong.
3: I have heard and seen people use all sorts of tank sizes for those kinds of depths and for wrecks.
4: You might be ok with the shorter tanks and avoiding the longer ones. Pretty much anything but HP120's style, most other sizes are smaller and wouldnt cause too much of a trim issue (85's, 95/119's, 100's, 104/130's all possible from size). SAC rate gives roughly 40cuft if you spent the whole NDL time at 130ft on 32%, plus a bit for emegency, you could get away with fairly small redundant tanks, but of course going deeper you will set the bottom time and deco time on the way back up, which could add considerably (2.6cuft/min @ 187ft - that is assuming no stress, which the wreck would add).

 

[The Kraken]

Simon, thanx for your response - and some good and pertinent questions!!!

1: Maintenance history - just the way I am

2: To some extent. I know there has been some discussion with respect to the HP tank/mixed gas issue. I didn't know if it warranted posting here, but I'd rather err on the side of safety. And, yes, I'm considering a tri-mix class, probably later this summer.

3: Good catch!!! Yes, setting a PO2 of 1.4 if diving on air, therefore the 187 MOD.

Once again, thanx . . .

 

[Doc Intrepid]

wetsuit or drysuit?
this your first set of doubles or you want another set?

If you're diving in a wetsuit in the ocean, consider getting a set of aluminum 80s and two more aluminum 80s for sling tanks. With your SAC rate at those depths you'll be good for two dives per day. First dive breath off the sling tank 80 until you take it down to 500 or so, then switch to backgas. You'll have rock bottom if you need it. You'll have most of your doubles remaining for the second dive without the sling tank.

You can almost get two sets of aluminum 80s for the price of one set of PST 130s. And with your note regarding 'mixed gas' that's something to consider; you ever dump a set of doubles with $40-$60 of a 30/30 trimix fill in them because that dive got blown out but now you need 18/45 for your next dive? It gets old fast. I have two sets of 80s, one set of 130s and a second set on the way. We still wind up shuffling sets around based on what happens to be in them, where we're diving, and the unpredictable nature of the weather offshore. Guess which sets I use more often, the 80s or the 130s?

You could do much worse than simply getting some sets of 80s - and like Simon said, if you extend your parameters to used tanks, hell you can find used 80s for $50 per tank in decent condition. Diving in a wetsuit, a couple sets of 80s and four or six sling 80s might be your most cost-effective option.

Just a thought. YMMV.

 

[simbrooks]

Just a thought. YMMV.

Sounds like the 12 days of xmas song, with the final day being "and a shiny new double garage!!"

I wasnt sure about buying old AL80's, my old HP120's have plenty of life in them, checked out the inside and they were sparkling for new tanks, no matter 15 years old! There are some finds out there, but if you can keep in with this LDS guy and his deal then the PST's are a good tank. I am looking to build my tank collection one day, but just some singles and a set of doubles thus far for me You might wonder about taking a VIP class if you have that many tanks, for that many tanks you could easily pay off a dive or a couple of mix fills for the price of a year's worth of VIP's! I am going to try to do that next year. Then buy some more tanks again

 

[The Kraken]

Doc,
Thanks for your response.

I'm diving wet.

You're waaaay ahead of me on the mixes right now.

At this point I'm still diving air and nitrox.

I'm looking for something with which I can maximize my current level of diving but something which I can easily move into my next level of diving. . . if such an animal does, indeed, exist.

 

[simbrooks]

I'm diving wet.

Contemplate a drysuit before you buy too many tanks - use your money for something that will keep you more comfortable on those longer, deeper dives than worrying about mix right away - get the drysuit and doubles down before you move on to mix - that is the way i am slowly trying to learn

 

[The Kraken]

Contemplate a drysuit before you buy too many tanks - use your money for something that will keep you more comfortable on those longer, deeper dives than worrying about mix right away - get the drysuit and doubles down before you move on to mix - that is the way i am slowly trying to learn

That's coming shortly after the doubles training. May be an age thing, but I seem to get colder much more quickly than I used to.

But I really want to get the doubles techniques and abilities down first.

 

[Doc Intrepid]

Doc,
Thanks for your response.

I'm diving wet.

You're waaaay ahead of me on the mixes right now.

At this point I'm still diving air and nitrox.

I'm looking for something with which I can maximize my current level of diving but something which I can easily move into my next level of diving. . . if such an animal does, indeed, exist.

Makes sense. Although, with all due respect, you really don't want to go much below 130-140 on nitrox, and certainly not to 187'

Especially if you are new to doubles and diving in a wetsuit in the ocean, my opinion (for what its worth!) remains the same - you could do much worse than a set or two of aluminum 80s. They offer desirable bouyancy characteristics under those circumstances, generally trim out well, are good for transitioning to the type of diving you're contemplating, and will remain useful long after you've graduated to deep wreck trimix dives. If you prefer steel and slightly shorter tanks, look at sets of double steel 72s. They are nearly equally cost-effective, and may be (judiciously!) over-filled to some extent to provide gas equivalent to sets of aluminum 80s. Best of luck to you during your transition.

Doc