Can of worms...Planning which Cylinders to Use?!

[Justin Owen]

OK, here we go...

I'm just about to complete Sports Diver, and so we start to look at being more self sufficient and providing our own redundancy for when the brown stuff hits the fan...

Most of my diving is from a rib, off Anglesey, and up to now has been sub-20m stuff. The more challenging dives the club organises (which always get blown out) are still only likely to be around 30m.

Practically everyone up to now has got themselves a pony cylinder - which as has been discussed before, is probably the cheapest way to get yourself set up.

So, given my diving, do I rush out and buy a pony, or, consider a twin-set? My first thought was that a twinset would be too big and heavy and awkward, but after lugging 15L+pony setups out the water I can't see how they can be any worse!

My second consideration is what do I need to learn? As only one other person uses a twinset at the club, where do I find information on shutdown procedures and other considerations?

I want my rig to be small, compact, and neat. My air consumption is good, do I consider twin 7's? Or should I look further to the future a go for twin-10's? As I said above, most diving will be with sub-30m with limited or no deco.

What would you suggest as to types of wing/harnesses/regulators? Where do I learn about configuration of equipment (apart from Dominics web-site!?).

I know everyone will have a different opinion - and I have read the other posts regarding redundancy too - but you guys are still the best source of info, so i'd appreciate your comments...!!

Thanks.

[Dominic]

When it comes to weights, Justin, these facts & figures are from the Faber website:

Size Lightest Heaviest
3           3.4         3.8
7           7.6         9.1
10          10.9       12.4
12          12.8       15.2
15          16.4       18.6

So the lightest twin 7s will be 15.2kg, the heaviest 18.2kg
The lightest 15+3 will weigh 20kg, the heaviest 22.4kg

When it comes to bouyancy, the differences are:
15+3 light = 1kg positive
2x7 light = 1.2 postitive

15+3 heavy = 0.9kg negative
2x7 heavy = 1.38 negative

So your lead requirements will be pretty much the same, but the cylinders will be 4-5kg heavier with the pony route.

In terms of size, I've checked my own twin 7's against a 15+pony, and found them to be the same width and less height - so twins are unquestionably the smaller setup.

Originally Posted by [b

Quote[/b] ] My first thought was that a twinset would be too big and heavy and awkward, but after lugging 15L+pony setups out the water I can't see how they can be any worse!

That was my first thought too, and so I bought a pony.
After discovering it was a rig I couldn't actually lift without a buddy to help me, I was delighted to discover that my twin 7s can be swung up with ease, even with all my lead bolted to it as well!

I hear a lot of negative things said about twinned 10s - generally down to them being too short for comfort. Have never tried them myself tho.

If twin 7s do have a downside, it's that you're unlikely to get two dives out of them unless depth is on your side. This doesn't usually cause me any problems, but it may be a consideration for you..

Originally Posted by [b

Quote[/b] ]What would you suggest as to types of wing/harnesses/regulators?

Well, I use a Buddy wing because it was good quality and cheaply priced. Wings like the DR Classic are popular, but probably too big for a small twinset.
I have a 1-piece harness, wouldn't even consider breaking it, as I've become very fond of the feeling of security you get from an unbreakable harness - I had a clip fail on me once, it's reassuring to know it won't happen again.
As for regs - whatever you use at the moment should be fine, just add another first stage. I got myself an Apeks DS4 when I went over to twins.

Originally Posted by [b

Quote[/b] ]Where do I learn about configuration of equipment (apart from Dominics web-site!?).

Where else do you need?

[And]

<font color='#0000FF'>Hi

A twinset is nice to have although expensive if you plan 2 dives off the club rib (you'd need two sets of 7,s or twin 12's). There is a lot of info on this site regarding setup and valve drills etc. In my opinion a good attentive BUDDY with same kit, and properly practiced at out of air drills is far better than any individual piece of kit!

Find more info on equipment on http://www.dir-uk.org/equipment.htm . There is a good word document which goes through everything from mask to fins, twinsets, ponys, regs the lot.

Kindest Regards

WL

[Richie]

Ignoring the DIR argument WL, (I did go into your temple in Portland at the w/e - nice kit ******* expensive though), I do not agree that you need two sets necessarily. It depends on who you are diving with and the type of dives you do.
I use independant 12's and often dive with people on 12+3 or 2*7 configs. I get balance, redundancy, avoid the hassle of midday fills and the odd gripe from the skipper about weight.
Works well enough.

[And]

<font color='#0000FF'>Hi

I meant that he might need two sets of 7's if he chose 7's because of the weight. Twin 12's are excellent, you only need one set, but a lot heavier. If doing UK dives from a rib in the 20-30 mtr range a single set of 7's won't leave enough reserve to complete the second dive safely in my opinion, not even 300 bar ones.

Kindest Regards

WL

[MATTBIN]

At this point would it not be fair to say then a 12L &amp; pony would be a better bet as you could also have a second (spare)12L for the second dive (or even hire one for the day) whilst still using the original pony as backup. A second 12 would be a lot cheaper than a second twin set.

Matt

[Dominic]

Hell, if you've already got a single, or are planning on hiring one, give Kent Diving a call and order an air decanting whip - £55, IIRC. I might well be flogging mine soon, for that matter..

Then take your twin 7s and a single with you, and stick some air back into the twins to give yourself enough for your nice, shallow, second dive.

[RobK]

Originally Posted by [b

Quote[/b] (MATTBIN @ July 03 2003,14:37)]At this point would it not be fair to say then a 12L &amp; pony would be a better bet as you could also have a second (spare)12L for the second dive (or even hire one for the day) whilst still using the original pony as backup. A second 12 would be a lot cheaper than a second twin set.

Matt

But if you're going to carry around two single twelves and a pony, you might as well just go for twin twelves in the first place.

If you really, really don't want to go for a twinset but still want redundancy then I reccomend getting a 7L Ali and rigging it like a stage. That way you're pretty sure never to outgrow it.

[MATTBIN]

Except on the dive you would be using 12l &amp; Pony which would also be OK on a bimble, whereas twin 12's might be a bit of overkill? We are also looking at what kit to buy after originally purchasing a 12l &nbsp;that will satisfy the next stage (and hopefully beyond), to me it looks as though twin 7's would soon be outgrown whereas the pony could be used as stage gas later on or as a simple pony with a single 12 for those shallow dives. I might be wrong anyone bought twin 7's and stayed with them for a long time or moved onto 10/12 twins?

Matt

[Dominic]

I bought my twin 7s from new and have just got them back from their first test.. mind you, with moving home and two car accidents, I haven't done as much diving as I'd have liked with them &nbsp;