Twinning questions

[PapaBear]

I am looking to progress to diving on a twinset by this time next year and thought I would begin doing some research now as I am beginning to build myself a wing to replace my BC and thinking about what will come next.
Before I get stuck in I should probably explain that I am a relatively new diver with about 70 dives under my belt mostly in the last year in the UK apart from a week at Sharm. Oh and I'm a BSAC Sports but have begun working towards my Dive Leader.

My regular buddy and I have often discussed going the twins route so that we can do longer dives at increasing depths (though for us this means 35 meters for now). Having done the thistlegorm Im feeling even more encouraged to do so!
Nobody in our club dives anything more then a 15ltr and a pony and I have quite a few questions though,

What is the most often used/recommended method of twinning up? Individual cylinders or manifolded? I haven't bought a cylinder yet so dont know but are there any manufacturers who should be avoided or recommended for cylinders and manifolds? What is the reasonable price I should be expecting to pay for the twin setup?

On a manifolded setup would an air integrated computer give a combined pressure reading from both tanks or just the one? Would my Legend regs be okay for use with twins? from what I understand most twin divers use either apeks or scubapros, is this just preference rather then a technical need?

What have I forgotten to think about?

[rustferret]

For me I use an isolating manifold so I have the option of diving with the my tanks (twin 15s) running independant.
This is good if your not comfortable with shutdown, but you will need to switch tanks/regs regularly normally every 50 bar so in the case of a free flow you have resurve. But I found that switching regs was a potential opertunity for a free flow.
Or you can run with both tanks linked and use the isolator to seperate your tanks as part of your shut down in the event of a free flow.

With regard to your regs I use both Ledgends and Posiedon extreams on mine and I'm looking to switch my posiedons to another set of ledgends as I find them far better. Ledgends are basically Apex any way.

I know you didnt ask about tank size but I would suggest you go for twin 12s, 10 are too small I know some one who has twin 10s and moving to deco diving he finds there not enough. 15s are great if you dont mind the weight.

Oh if you get the chance see if you can have a try dive on some differant setups to see what you like.......PM me if you want to try twin 15s.

What club are you with?

Rustferret

[PapaBear]

I didnt know that about Ledgends, have to admit I did fear hearing I would have to change as I find them a lovely reg. 12's were the size that I was thinking of, although I prefer the size and weight of a single 15 normally over the 12 I dont think that I could handle two of the things!!

[rustferret]

Yep Ledgends are dam good regs dont change loads of peeps use em with twins.

are you with Hull 14?

Rustferret

[Steve S]

If you are only going to dive twins occasionally it may be worth diving independents, I dived indie 10's for a couple of years and found them fine with the caveat that I couldn't do the dive time I wanted on a second dive without a refill.

I choose 10's as I used them with a bc and was worried I may not have had enough lift with larger bottles.

I had a gauge on each post and just one second stage with a direct feed as well. You have to be disciplined and switch regularly, I did it every 30 bar and usually surfaced with the same amount in each.

I now dive inverted manifold 12's and find this the best setup for moi, obviously unless you can reach the isolator you are diving a very large single cylinder with no redundancy, something to bare in mind when choosing.

I can't help with the reg choice as all mine are Apeks TX 50's and I just use one gauge running off the side I'm breathing from.

I would go along on a twinset familiarisation day that you see advertised I know Mark Powell does them as does Go-dive among others.

Good luck and don't worry it's not rocket science

Safe diving,
Steve

[Ian@1904]

I suggest that you avoid Beaver valves. My cylinder valves failed their 2.5 year test in the summer, I was stunned at the time. Fortunately my LDS has an excellent approach to customer service.

You should also consider what wing/harness/backplate arrangement you feel comfy with.

Twinsets are quite heavy, buy a decent trolley.

Regs are regs, if you are happy with what you have, use them.

Don't know if you use nitrox, but if you are diving in the 30-40m range then consider using nitrox

I like to have a gauge for each cylinder. In my case I have a standard pressure gauge, the other is my gas integrated computer (Suunto Vytec)

Some people really struggle to start off with getting their trim right. So start of in the swimming pool or max of 6m.

[Woz]

If you are going to only occasionally dive a twinset, twindie 12's work well and will give you the flexibility of 2 singles for a club trip dive without having to fill them at 1/2 time.

Personally I wish I'd gone for twindie 12's. I've got an isolated pair and while they're very very good at what they do (one deep dive or 2 smaller ones) they are a bit inflexible when it comes to club diving. Great on hardboats, though.

Still- as a kit tart I've a single 12 as well.

If you would like to talk it over then let me know by PM and I'll send you my email/phone no as at this stage is easy to blow lots of cash on kit.

[Far_X]

I am still trying to convert the litre sizes to the American sizes they use over here. Hmm, I found a page that gives me what I need to know but it gives both of my twins (15.3 litres each tank) as having the same water capacity yet I know I can get more gas in my newer twins as it has a higher pressure rating. I am almost sure you don't use HP and LP in England.

I use an isolating manifold which in effect means I am diving on the one tank. If I have a problem with either tank, I can isolate the problem tank by closing the manifold and the dive is considered over at that point. If I have a problem with my manifold, then I am on my buddy's tanks and heading for the surface. Using independent twins, you have eliminated the manifold problem. But then you suddenly need more equipment as you need a gauge for each cylinder. I don't dive with independents - what would you do for the inflator hose - question for those that do. Do you have two of them?

I have Apeks 100s and love them. I have a pair of 40s which I use for single tank beach dives. BP/W is the way to go and the beauty about that is you can have different wings for different gear set ups. I have two wings, one for single tanks and one for twins.

Cannot give you any advice on manufacturers as we don't always have the same gear available to buy. Neither can I give an expert opinion on air integrated computers. Being a programmer myself, I am sticking with the SPGs for now.

Good luck in your quest.

[Big Andy]

No one's mentioned twin 300 bar 7s yet. I've dived the lot over the years, single 18, 18 with a pony, 15 ditto, twin 15s, twin 12s and now twin 300 bar 7s. I've had the 7s for about 5 years and wouldn't dream of diving anything else on OC. No heavier than a single with pony (less lead 'cos they're denser).

They give the best balance / trim / weighting combination of anything I've dived in yet. You can do Beaver set at a reasonable price or pick up some Fabers and slap a Sanosub manifold on (MDE still O/S).

I know there are issues of getting 2 big dives out of 1 fill but a 12Lit 300 bar and a decanting hose sorts that out when staying out all day.

Coverting a reg to DIN will cost you about £25 and you'll need to be DIN (M26 or 3/4 BSP converter) for next summer if you're doing EANx anyway. Most Regs will be OK for this (including yours) but I would use S-Pros, Apeks or Poseidon - not in that order, by preference.

You've a huge choice of wings from recreational to CD, Poseidon or something techie like a Halcyon. I do like the new Poseidon Platform - the quick release is great and no bits to get in the way.

Isolation manifold is nice but statistically they don't really add to safety (chance of forgetting to open when filling / diving -v- slight chance of manifold bar failure).

Best advice of all - as has been said, try them all if possible to see what works.

Have fun

[mala]

i went for indies as a bit of an experiment before perhaps going for a manifolded set up.
that was 2 years ago and i'm still with indy 12l.
i use cam bands as this gives great flexibility with swopping things about and for generall transportaion.

2p