help with doubles

[Isurus9]

Some of you are beating this guy up for no reason. He never said he was going to jump in and start diving the Andrea Doria tomorrow; he has a valid question and was hoping for some help.

When I started diving doubles I was not in a tech class, I was just an Advanced Open Water diver but I knew eventually I was going to go the tech direction, I only had around 40 dives and just wanted experience in them as was recommended by my eventual tech buddy. During my tech class there were 3 other people in it, none of them had ever dove a set of doubles before, I was the only one who finished. Not because I was the "best", but I was the most familiar and comfortable with my gear configurations since I had logged almost 50 dives in just doubles, no stages or any of the other stuff you guys are adding to the poor original poster.

So the original question was answered, bands, manifold (DIN with rubber knobs if you plan on tech), and if you don't have already two 1st and 2nd stage regs (you should always buy balanced and they don't have to be Scubapro MK25/S600), 6' hose, necklace, backplate/harness and wing. It can be a fairly significant financial investment and if you are going to go the tech route you have to satisfy all three "E's" of scuba diving, "Experience, Education and Equipment." Don't skimp on the Education. (My disclaimer)

 

[MBH]

That price for the Mk25/S600 seems a little off, the MSRP is $665 not a big deal but still.

I can loan you the $35.00.

I'm giving the OP the info on what he can expect to pay in the retail market. Perhaps you should go the the trouble to give him the EXACT figures, quote him a price, include shipping, and then deliver him a full set.

Hopefully, since he is internet savvy, he will shop around, buy a part at a time, and come out ok.
ok?:mooner:

 

[NakedDiver]

Are you really serous about this? with that number of dive logs. My recommendation please take sometime to study serious stuffs like this before you do it. Moreso i'm afraid you also need a DAN insurance to come with it....Goodluck..

 

[Colliam7]

MBH provides an excellent cost summary! You can tweak things in the list, but it is pretty comprehensive. An additional way to look at it is the sequence - what are the initial, primary costs to set up doubles, and what are the subsequent, secondary costs to actually dive them, which he puts in as well. To double up the tanks, all you really need are bands and a manifold. If you already have tanks (since you asked for costs 'sans tanks', that may be the case), you should understand that you will still need to replace the valves, and the Sea Elite costs that MBH mentions includes new valves. So, your primary costs are relatively modest. Once you have the tanks doubled, then the costs for regs (either two, or one in addition to what you have), hoses and SPG comes in. Finally, the BC to carry them - most probably BP and wing - comes in.

 

[DA Aquamaster]

It's true that doubles give you enough gas to get into serious decompression trouble. But saying more gas is bad has a long history that does not bear out the "more gas is going to kill you if you are a new/rec diver" theory.

For example, the original steel 72 was considered to be an ideal size as the popular theory was that a diver could not get bent on a single tank dive with one as it did not have enough gas to allow the time and depth to do so. For a hoover this was probably true, but for an experienced diver with a decent SAC, you started to get into potential deco territory at around 90 feet with US Navy tables and a steel 72.

That said, many divers still dove twin 72's and planned to do two dives with them and did not get themselves into trouble, nor did the incidence of bends go up when 77 cu ft AL 80's came along, or for that matter 100 cu ft AL tanks. Finally no one would be busting this guy's chops if he wanted to dive a single 130 - offering nearly the same capacity as a set of twin 72's. The point is not how much gas you have but how you use it and a lack of brains will get you dead on a single tank almost as easily as on two tanks.

Personally,I think you should be comfortable with both doubles and a dry suit before you start a tech class as managing both the doubles and the dry suit should be second nature by then so you can focus on the material in the course. It also lets you get two major purchases out of the way before you begin spending even more cash on more technical equipment and training.

I normally look for decent used equipment if possible. The last two pairs of X7-100's I bought were $600 and $650 per pair and were both less than 1 year old. I have never paid more than $100 for a used excellent condition dual valve 232 bar isolator manifold and I have never paid more than $170 for a new one. Bands vary slightly by quality and greatly by price. At a minimum you want bands with welded reinforcing plates in the center where the bolts go, but the differences beyond that are slight and mostly pose assembly challenges rather than any operational or diurability advantage. I have spent between $80 and $150 for new bands and have gotten used sets as cheap as $25. They need to be sized to match your tanks (7", 7.25" and 8"). A bolt kit, if not included with the bands, will run another $20-$25.

So realistically with new steel tanks you are looking at $700-$1000. With double AL 80's you can reduce those figures by $200. and you can reduce them by another $100-$200 if you go with used steel 72's. Both AL80's and steel 72's are decent choices for a wet suited diver as they do not get so negative during a dive and most divers can still swim them up in the event of a BC failure.

The slightly positve nature of AL 80's also makes them very stable during the last half of a dive, so they are good choices for an initial set of doubles. The bands used will work well with E7/X7 series tanks later on if you move to larger doubles and the AL80's themselves can then be used individually as stage bottles. So this is a good route to go in order to minimize both initial and long term investment in technical equipment.

You'll need to add another regulator and probably a BP/wing as most BC's are not doubles freindly from attachment, stability or bouyancy perspectives. I tend to buy good used Scuabpro regs as a used Mk 20 S600 or Mk 20 G250 offers 100% of the performance of a new Mk 25 G250 or S600 at less than half the cost. The Mk 17 is also an excellent technical reg for doubles (I prefer it to the Mk 20/25) but there are very few on the used market (which says something very good about them).

 

[TSandM]

Just to add to the discussion, I'd also add that, unless you already have a pair SPARE tanks you want to double up, consider looking around for a used set. I've bought three sets of doubles used so far, and have paid between $350 and $500 a set for them (two sets of steel 72s, one set of Worthington 85s). Just be careful and educate yourself about manifolds, because there are some odd ones out there that you might not want to have.

I'd also say that it is my personal opinion that time spent in a single tank, perfecting buoyancy control, trim, and propulsion techniques, is time well spent. I spent a year plus in a single tank, and going to doubles wasn't that big a deal. A friend of mine moved to doubles at about 40 dives, and I think he struggled more than he needed to.

Finally, doubles are a prerequisite for technical training, and if you know that's the direction you want to go, then you'll have to have them. If you're just looking for a bigger gas supply because you're going through your gas too fast, look into buying HP 130s instead. They're lovely tanks; they trim out beautifully and hold enough gas for just about any recreational dive anybody's going to do.

 

[Randy43068]

I am looking to purchase a set of doubles. I need all equipment needed ie. bands whatever else. About how much should it cost minus tanks.

Were I you, I would shop for a used set that is already put together. I'm sure it will be a lot cheaper than if you put a set of twin tanks together with parts purchased separately.

Whatever you do, buy the best quality you can afford, and then some.

 

[Colliam7]

Just to add to the discussion, I'd also add that, unless you already have a pair SPARE tanks you want to double up, consider looking around for a used set. I've bought three sets of doubles used so far, and have paid between $350 and $500 a set for them.

Very good advice on two levels. 1. After I doubled up my 120s, I realized I no longer had any single tanks to dive (and breaking them down and setting them back up, in order to dive them as singles and as doubles is simply too much work.) 2. I also got a set of used double AL80s AND a 30cf pony for $300 (plus costs of hyrdos). Turns out, they have become a nice coastal rec rig, or perhaps my single-tank equivalent.

 

[mpd525]

Are you really serous about this? with that number of dive logs. My recommendation please take sometime to study serious stuffs like this before you do it. Moreso i'm afraid you also need a DAN insurance to come with it....Goodluck..

hey that's great advice, thanks for you expert opinion, and the willingness to help out somebody that's asking a question about gear, and not you opinion on whether or not he's ready or not. Kudos to you

 

[Jim Lapenta]

My first set of doubles were steel 72's that I had already and just needed put together. Cost of the tanks was roughly 75 each used, 130 for a manifold I got new off ebay from Divers Supply, and a set of bands from TDL when they were running a special of 75 bucks for em. So 355 for that set. My lp 85's were new all the way around. Dive Rite 300 Bar manifold and bands, Total cost 725. My 95's I got real lucky! Met a guy in Fla from Minnesota who was getting out of cold water diving. Tanks did need hydro but he'd had them in his garage and never dove em. Still had original price tag and receipt which I have for what he paid for them in 99. Cost him 750 and change. I got em for 369 including shipping from Minnesota to Pa. He liked me and my wife and wanted to be fair. I'd say that was more than fair! I also have 2 more 72's as singles, 2 HP 80's and an AL80 for pool and to stage rig at some point. If you look around you can still get standard AL 80 for 150 bucks each. Manifold for 165, Bands from Joel at TDL for 100 regular or one of their sales for 75. So figure 500-525. But you'll need the extra reg, a BC that will handle doubles correctly(BPW), and all the other little goodies you'll want once you start down the path. So figure about a grand if you go aluminum new or 1500 or more for steel new. Used you can do alot better but don't forget shipping and service of everything (cept the BPW) since the tanks will most likely need vis'd(perhaps hydroed as well) and the reg checked.