Advice on buying twin tanks

I'm looking to get a set of doubles for diving in SF Bay Area and would appreciate some guidance. I currently have two XS HP Steal 100s and one AL 80 but would probably leave them as singles since doubles would be overkill for most of my fun dives with friends or Reef Check surveys. Don gave me the awesome advice of the steel 100s for single tank diving which has since converted many and the rest simply covet.

A few questions / room for comments:

* Recommendations on size, steel vs al, hp vs lp etc. Given how difficult it is to travel with tanks, assume these would be for California recreational diving but also serve me in Tech classes

* Any other things to consider as some people have begun favoring sidemounted doubles for some conditions?

* Will eventually need a deco bottle so same questions

* This can't be an original question, any links to where this has been discussed at length from people you trust appreciated

* Do any of the shops in the area rent doubles?

* Looking to part with a pair at a reasonable price? Drop me a line

Cheers,

brian

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Permalink Reply by Jay Schier on February 19, 2012 at 10:52am

Hey Brian, to best answer your questions you must answer other questions,
- do I have an idea what my dive profiles will look like? My SAC rate is?
- do I dive wet or dry, or both?
- do I need lots of lead when I dive?
- will I have to walk long distances with my tanks?

The generic set up (one that works for many people) is the twin steel 100's as they have very good capacity, balance characteristics and are decently priced. Wether to choose high pressure or low pressure could be body type ( long or short torso), also high pressure on your equipment is a consideration. Some like the size of HP's but use short fills to reduce the pressure on their equipment.
If possible, see if you can get a "test" dive in the different set ups, twin 100's, 120's, and especially side mount. Check out the Delta system as It can do side mount, singles and twins and can be easily configured and changed. An essentials course (either tech or side mount or both) would not only give you a good idea before you buy but give you a good comparison of the set ups as well as the informed opinion of your instructor.

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Permalink Reply by Ray Nixon on February 19, 2012 at 2:12pm

Hello Brian,

Looks like you find yourself teetering on the fence many have sat on before. You love the benefits that your steel cylinder has given you, but you see into the future that you are going to be needing a bit more gas for some of your dives. You could go the traditional route of twin steels, but then the inevitable limitations of them crop up, how to travel with them, or if not, being faced with renting what's available at your destination, etc. But consider this... I recently purchased a Z system and I think you may be an ideal candidate for one too. For the same money or maybe even a bit less than your cash outlay for tanks, bands and a manifold, you can completely revolutionize the way you dive. The limitations you are now faced with will simply no longer be relevant. The Z System would, in my opinion, be superior to what you are considering in the following ways:

1. You would be sidemounting 2 aluminum 80 cylinders, so you'd have all the advantages that go along with that right off the bat. Lighter weight, freedom of movement, enormously easier to maintain proper trim, better safety making surf entries, better flexibility in terms of equipment placement, etc. Also you won't have to worry about wet or dry, how much lead, or what your sac rate is. You'll be infinitely adjustable and adaptable to any dive at any location.

2. 2 aluminum 80 tanks will be plenty of gas for you for awhile. When you don't need 160 cu ft, just take a single bottle. When you're ready for a deco bottle, well you just clip that one in there as well. In anticipation of you reiterating that you love your steel 100, believe me I get it, but that love will pale in comparison to your love for your Z system. If you think your mates covet your tank, wait till they see your sidemount setup.

3. Travel restrictions - absolutely none. Getting to your destination with your gear will be zero headache. And no additional expense. With no backplate to worry about, the Z system packs up into a nice tight little ball in your bag. Throw in a couple of travel stage kits and you can put them on rental 80's at any dive location.

UTD sidemount is quite simply the future of diving and you are perfectly positioned to transition to it. Reef survey? Sidemount. Tech 1? Sidemount. Rebreather? Sidemount. Cave? Sidemount. Scooter? Sidemount. Sidemount. Sidemount.

My advice to you - sell at least one of your steel tanks and get a second aluminum 80. Then call Costa at UTD and order your Z system. While you think about it, check out the equipment pages at

http://www.utdequipment.com/zsystem1.html

Also feel free to call Andrew or Jeff directly. They can definitively answer any remaining questions you might have. Hope this helps.

Ray Nixon