Do BCDs that take Single Cylinders also take Twin Sets? [Archive]

MattV

23-10-2010, 22:09

Hi,

I know this may sound a bit funny to some of you (the ones with lots of experience) but after endless searches over the internet, I still haven't found the answer for the above question that's been bothering me for months.:confused:

I've always rented BCDs because I found most clubs (in the UK) and abroad, have decent enough BC (for the training purposes at least). I really want to get my own now (finally) as I'm clearly going to do more and more diving at home. After hours (>20, seriously) of reading reviews I narrowed them down to 3-4. One of them is the Cressi S300 (classical, durable, plently of lift, etc.). Read the reviews in "Dive" (August issue, p39) and quite liked it. However, I'm still confused about whether you can use a twin set (dual cylinders) with this BC, or in fact for any BC.

For the record, I'm not certified (yet) to use a twin set, but I really want to take the TDI's intro course at Wraysbury as soon as possible. If any of you who know/use twin sets (not just the trimix users :)), could give me a bit of info on a few things I'd really (really, really, really) appreciate it:

1. Can one use twin sets (or cylinder/pony config) on any BCD?
2. If you need a "special" BCD, what are the key features you need to look for?
3. Do you need an extra configuration (e.g. extra bladders) to compensate for the increase weight distribution on your back (assuming you use high capacity steel cylinders)
4. How many D rings do you *actually* need. Is 4 of them enough?
5. Where can I find a clear review of "current" BCDs (e.g. on the market 2009-2010).

I'm aware that the answer might be very simple, but I just havent' been able to find it on my own (...doh):(

Many thanks in advance!

AndyA

23-10-2010, 22:43

Firstly you dont need to be certified to use a twinset, its useful to have some input/training from someone experienced in using them but its not compulsary.

You can use twins with BCD's but what you have to be aware of is the lift capacity. For a twinset you need more lift than a fair few BCD's can give.

I know you can use twins with the buddy range bcd's and some of the Seaquest range, I dont know about any other brands though.

If you are considering going down the tech route then consider buying a wing/backplate setup. A single tank wing is a great piece of kit and if you do decide to go down the tech route then all you need is a bigger wing to use with your harness and plate. There are some wings that can apparently take single or twin cylinders, but I have no experience of these.

Hickdive

23-10-2010, 23:16

1. Can one use twin sets (or cylinder/pony config) on any BCD?

If it is has sufficient buoyancy to support the twin set or single/pony then yes, you can use any BC for them. However, there are lots of other considerations. For example, if you're using an isolation manifold then you must be able to shut that down. That might mean using a slob knob or inverting the set. It is harder to do a 'normal' reach behind the head shutdown on a conventional BC than with a BP&W.

You might find this site useful;

http://www.subaqua.co.uk/cgi-bin/cylinder-buoyancy.cgi

2. If you need a "special" BCD, what are the key features you need to look for?

Buoyancy is the key consideration. After that, can you shut down in it if you're using an isolation manifold.

3. Do you need an extra configuration (e.g. extra bladders) to compensate for the increase weight distribution on your back (assuming you use high capacity steel cylinders)

Correct weighting will remove the need for extra bladders. You need to weight for neutral buoyancy with nearly empty cylinders. Then inflating your suit, swimming up and/or dropping ditchable weights will make you positively buoyant if you have a bladder failure at the start of the dive when the cylinders are a their heaviest.

A BSAC Buoyancy and Trim workshop will help you play with weighting and buoyancy.

4. How many D rings do you *actually* need. Is 4 of them enough?

You can manage with 3 ;-) but four is ideal for most folk. More D-rings just tempt you to add more danglies for that 'xmas tree' look.

5. Where can I find a clear review of "current" BCDs (e.g. on the market 2009-2010).

Can't help you there, except to say you won't find it in BSAC 'Dive'. I'm sure at least 3.5 pages of full-colour advertising had no influence at all on on the marks a certain brand of drysuit received in review this month.

MattV

24-10-2010, 02:05

Many thanks guys, really appreciate your help.

I get the buoyancy part -makes a lot of sense. I'm still not clear about how you attach the bloody twinset to the BC though. With a single cylinder is fairly easy - just strap it on (1 or 2 straps). Do you do the same for the twinset (assuming the manifold and the metal bands holding them togeter are in place). So you just need longer straps?

If it is has sufficient buoyancy to support the twin set or single/pony then yes, you can use any BC for them.

Yup, that's why I looked at something with ample lift. Those pesky travel BCs looked too frail.

Can't help you there, except to say you won't find it in BSAC 'Dive'. I'm sure at least 3.5 pages of full-colour advertising had no influence at all on on the marks a certain brand of drysuit received in review this month.

Umm... that puts most of us 'less seasoned' bubblemakers at a considerable disadvantage. Considering the high costs involed in purchasing equipment and the biased reports ...

Anyway, that's a different kettle of fish.

If you are considering going down the tech route then consider buying a wing/backplate setup. A single tank wing is a great piece of kit and if you do decide to go down the tech route then all you need is a bigger wing to use with your harness and plate. There are some wings that can apparently take single or twin cylinders, but I have no experience of these.

Well, I'm excited about being able to stay longer/go deeper, but I'm not a techie desperado yet. Its something I'd like to try, hence I wouldn't want my equipment limited. It costs more to buy 2 crappy BCDs than a *good* one (whatever *good* means these days). When I got my reg, I spent a ***LOT***:p but I've never regretted it. Trying to repeat the performance for BCDs- pretty confusing with the limited info and all commercial sale-talk.

Hence I turned to you nice people. ;)

PeteM

24-10-2010, 08:20

I'm still not clear about how you attach the bloody twinset to the BC though. With a single cylinder is fairly easy - just strap it on (1 or 2 straps). Do you do the same for the twinset (assuming the manifold and the metal bands holding them togeter are in place). So you just need longer straps?

With a back plate/wing you bolt it to the backplate so it is nice and solid. You can do that with a BCD but two metal 10mm bolts through a plastic plate as on most BCDs is not good for longevity, most people go for twinning straps as sold by AP Valves (http://www.apvalves.com/uk/aftersales/spares/sparedetail.php?codeID=10), these do not hold the cylinders rigidly enough for a manifold so you either need metal twinning bands as well or you have to go with independent twins.

I would suggest that you go with a back plate/wing setup and build it yourself. It is easy to do (you are not building it from scratch you are just putting components together), can save you money and gives the maximum flexibility. That way you can get something that exactly suits you and if you do make a mistake you can easily and cheaply fix just that bit. You can use second hand bits for this as the only bit that you have to be careful with is the wing.

See here for instructions here (http://www.gasdiving.co.uk/pages/misc/kit/harness_2.htm)

A lot of the prebuilt harnesses are vastly overly complex, with buckles and D rings all over the place. I think this is an attempt to justify the stupid prices. All you need is three or four D rings and one buckle. Some people find it useful to add a single shoulder clip on a loop to make it easier to get in and out (see here http://www.ukrecscuba.org.uk/ukdiver/harness/index.html for how) but I never bothered. So your total shopping list is a few meters of webbing, 4 D rings, 6 (metal) weight retainers, a weight belt buckle and a clip.

For the wing make sure you get a twinset wing, the single cylinder wings and those that do for both do not work as well with a twinset as they cannot inflate properly. A big mistake people often make is to buy too big a wing. I've got a diverite classic which gives (I think) 55lb and that is the upper limit of what you need. I can happily dive with four cylinders on that with it only half inflated. If I was buying again I would aim for 40lb-45lb.

Nigel Hewitt

24-10-2010, 08:41

I found some holes in my Scubapro Club, this was over ten years ago, and bolted a twinset to it. It worked for a couple of dives although it was pretty much on the limit for buoyancy if I'd flooded the suit.

BogSnorkeller

24-10-2010, 10:58

I've just made a twinset rig out of my ancient Buddy Commando. Here's what I've learned:

1. Buoyancy - no problem. The Commando is a hell of a lifty wing, but apart from that - twin 7s are lighter in the water than a 15 and a pony. I think the main buoyancy issues come if you start going very deep with lots of extra stages and whatnot.

2. Attaching the twinset to the wing? My technique was as follows:

Clamp my two cylinders together using steel twinning bands (£15 off ebay.)
Drill a couple of holes through the back of the BCD (i.e. through the fabric shell, the webbing waist strap and the plastic backplate.) You can tidy up the hole by using brass eyelets to clamp the fabric bits, which makes it easier to attach the BCD in a hurry.
I had to buy some new stainless threaded bar long enough to reach from the twinning bands through the holes in my BCD. (You'll need to use a few stainless nuts and big washers on the threaded bar - work that bit out for yourself.) I then cut the bars short enough that you can only just fit a nut on them. (You want to use a wingnut or similar - I am using some posh ones that someone on the Yorkshire Divers forum is making.)
Finally, check to make sure the wingnuts aren't going to be rubbing holes in the back of your drysuit when you're wearing your BCD. I've glued neoprene rings on the backplate to make sure the nuts don't stand proud.

>Here< (http://www.flickr.com/photos/deepseadamian/sets/72157625229074744/) are some pics to help clarify:

3. Your final decision is how to configure your regs. Personally, I don't have a hope in hell of reaching my valves as the cylinders sit too low down on my back. Therefore I don't bother with a manifold and just have them as independents - i.e. if one air supply fails, I don't mess around trying to shut valves: I just put the other reg in my gob and ascend. It may be different for you, or you may even consider using a slob-knob or mounting the cylinders upside down so you can reach the valves - have a chat with one of the beardies in your club to discuss the pros and cons. Don't forget to build redundancy into your system - i.e. have the BCD inflated from one cylinder and your drysuit from the other.

My rig feels very solid. It's very easy to bolt together and the cylinders don't wobble around. Obviously, I didn't choose twin 7s to dive the Titanic - I just like the way the rig is so beautifully balanced in the water. I am planning to put together some twin 12s to use on the same BCD - ridiculously cheap and easy: I just need to buy another 12 and some twinning bands off ebay and job done.

Richard Whitcombe

24-10-2010, 19:10

Most jacket style BCDs will "sort of" take 2 tanks. That's a bit different to a twinset. You can shove 2 x 12l tanks onto the back of a buddy commando etc.

Ive yet to see a BCD id class as secure enough to support a proper manifolded twinset and just the weight of 2 tanks is too much for most plastic backplates.

My ancient Mares BCD was rated single tank to 18l or twin 10s. I put a 15l and 3l pony on it, stood up, CRACK backplate snapped. Then again Mares are renound for producing low quality dive gear (except masks and fins).

The right tool for the job for a proper manifold twinset is going to be a metal backplate, wing and proper steel bands and bolts to hold them securely. And a wing with the correct amount of lift!

As others have said, you certainly dont need to be certified to dive with a twinset. HOWEVER, doing one of these courses might be useful in that the instructor will bring different types of setups regarding manifold, independent, wing, maybe BCD if he can find one, go through the pros and cons and give you the option to try one. Id suggest doing this before considering buying anything!

Don't think BSAC has got its twinset course out yet (yet another massively delayed failure) and even if it did you cant use the most common long-hose regulator setup so best to go elsewhere and get shown everything.

4. How many D rings do you *actually* need. Is 4 of them enough?

4 is maybe too much. Depends on your configuration. Far more important than number of D-rings is the positioning. On a proper wing and harness you can move these to exactly where needed - not possible on most BCD setups.

John Bantin

24-10-2010, 19:17

...or do a side-mount course.

Richard Whitcombe

24-10-2010, 19:21

You really have been spamming that across multiple forums for weeks now. At least this time it doesn't have the link to the school in as well!

MattV

24-10-2010, 21:03

Thank you all for your input. It's a real pitty they don't make more flexible config BCs. Maybe with experience I'll get more friendly towards the wings, but at the moment I really enjoy a classical BCD. I noticed that lots of people (and worryingly, lost of newbies like me, with less than 100 dives under their belt) stride for the 'techie' look, hence they jump on wings for their look alone. I must say that's a bit beyond me, but I might be obtuse. I love the classical BC with all the front "clutter" and the lateral baldders, pockets, etc. I'm probably the only diver on the planet who wishes to go techie without the look!:D I know, I know, I'm not cool, but I feel very confortable in those BCs. And I can get neutrally buoyant very easily in them. Wings just look... weird to me. I'm gonna ask someone whos got one to let me try it in the pool, see how it feels.

I'm interested in the twin setting because I'd like to take some TDIs courses. Some of UK's best wrecks are a bit deeper than 40m, so it would be great to go there. Or stay at 35-40 for longer (no stop times at those depths are ridiculously short). So you need more air, redunancy, twin sets... blah. I wish I had gills. But there's hope, my wife sais she's sure I'll grow them soon...:rolleyes:

As others have said, you certainly dont need to be certified to dive with a twinset. HOWEVER, doing one of these courses might be useful in that the instructor will bring different types of setups regarding manifold, independent, wing, maybe BCD if he can find one, go through the pros and cons and give you the option to try one. Id suggest doing this before considering buying anything!

Yup, thanks, that's exactly what I wanted to do. There are both PADI and TDI introductory courses on that, and I'm looking into which one is more comprehensive. I am PADI trained (you're probably not going to talk to me anymore now :o ). Unfortunately I'm not part of a club yet since I'd really like to join a BSAC club. I found BSAC members really friendly and helpful - hence I joined this forum, and I was right to do so.

Thank you guys for your answers you've been really helpful. I hope I'll be able to contribute back.

@PeteM - Many thanks for your input/links mate. After reading all that the penny finally dropped.:) Thanks!
PS: @Richard Whitcombe - I hope you don't mean I've been spamming. I've only joined this forum. Probably you meant in in re: to 'side mount course' comment. I actually wanted to ask what the heck is a 'side mount course' but I'm not gonna now :p

John Bantin

24-10-2010, 21:37

Yes. It reminds me of the times when I used to promote the use of diving computers, and, later, rebreathers and long hoses! Jill Heinerth told me at Eurotek that side-mounting has really taken off in the USA. What happens there happens here next year! (..and it was TWO posts on YD.)

Richard Whitcombe

24-10-2010, 21:52

There are both PADI and TDI introductory courses on that, and I'm looking into which one is more comprehensive.

Both will depend massively on the instructor. My advice is email him in advance telling him exactly what you're after to ensure he can tailor the course to what you need. As long as the instructor is sound either agency will do the same job (and likely the same instructor!)

I am PADI trained (you're probably not going to talk to me anymore now :o )

Thats fine - i earn a living teaching PADI and only teach BSAC for fun with the club (or did - i cant now as my equipment would make a trainees head explode apparently). Im also TDI trained at technical levels but not an instructor. You'll find a very large number on here are multi agency trained and/or teach for multiple agencies. They all accomplish the same thing ultimately.

@Richard Whitcombe - I hope you don't mean I've been spamming.

Yep, response to the side mount comment as its been used a fair bit elsewhere.

TerryH

24-10-2010, 22:22

Thank you all for your input. It's a real pitty they don't make more flexible config BCs.

Of course they do, they just havnt been mentioned on here yet ;)

There are BC's and there are wing/backplates and inbetween there are wing
BC's :D

The problem with many BC's as has been mentioned is a combination of
limited lift and not so secure a method of securing the twins etc.

A wing BC has the bladder independent of the jacket part of the BC, so it
can be larger and have more lift. The backpac rather than backplate is a
very tough reinforced, usually webbing matrix that will easily hold a twinset.

Depending on the make you'll get pseudo wing BC's which offer very little
over a standard BC and others like the Zeagle and Diveright that are on the
verge of a full wing/backplate.

I've got two Zeagle Tech wings which have a webbing matrix that can take
almost every variant thrown at them with ease and not a solid backplate
in sight. They dont like having a stage hanging off them too much, but for
anything from singles to twins they are the most versatile of systems you
can.

Try approaching it from the other angle. Instead of looking for BC's that can
take twins, look for wings without stainless backplates, might give you some
more ideas.

MattV

25-10-2010, 17:11

Umm, you know, I think I might settle for 2 separate rigs.

I'll get a 'classical BC' with plently of lift (S300 probably) and use it with a huge tank (18L - do they come in bigger sizes thant that?).

At some point (when I manage to save enough money for a new rig) I'll probably get a wing. At the moment I can't afford a twinset anyway.

I'll keep my eyes open anyway. Thanks a lot guys.

PeteM

26-10-2010, 08:13

Umm, you know, I think I might settle for 2 separate rigs.

I'll get a 'classical BC' with plently of lift (S300 probably)

Not a bad idea, I still have my old BCD for holidays etc. But if I were starting again I would buy a single tank wing then when I bought the twinset I would just need to buy a second cell. Initial cost is likely to be similar or less, long term far less.

and use it with a huge tank (18L - do they come in bigger sizes thant that?).

Biggest cylinders I've seen is 20L. But you need to think about everything to do with cylinders before going down this route. There are major problems with large single cylinders.

Cost: Will have to buy new and will almost certainly be a special order therefore not taking advantage of the suppliers bulk buying of standard 12L and 15L cylinders
Deprecation: When you come to sell (which you will) you will loose a fortune as there is no significant second hand market for big cylinders
Centre of gravity: Sheer bulk moves the centre of gravity further away from you which makes it less stable underwater and harder to carry out.
Safety: This is the big one. Carrying two cylinders is not just for the extra capacity it is to give you bailout options. If you loose one side you still have the other to get back to the surface. A large single gives you the gas to get into deep trouble but with not the redundancy to get out

MattV

26-10-2010, 12:06

Not a bad idea, I still have my old BCD for holidays etc. But if I were starting again I would buy a single tank wing then when I bought the twinset I would just need to buy a second cell. Initial cost is likely to be similar or less, long term far less.

I can see your point. However, I've never dived on a wing. My attachment to BCs comes from a day with really choppy seas when I floated on a really good BC for over an hour, until the boat finally saw us. Several reviews of wing BCs cautioned of the fact that they tend to push you face down (which is perfect under the water, but not so good on a choppy sea topside). Now, I'm a good swimmer, and in relatively good shape (except from my belly who seems to have a mind of its own and resists my running and gym assault :D), but I was quite tired after an hour of swimming against a mild current, and then trying to keep my head above water for another 70-80 mins in choppy water.

Maybe this is childish, and more experienced divers would laugh at the above story, but I'm not so sure I would. How do you find your wing BC? Are those reviews true, or just a load of BS to keep the market going for classical BCs?

This is one of the things that really ****es me off. In my day job, I can tell instantly if someone is talking rubbish in my field of expertise. With diving, I am dependent on other people's opinions, and there's no guarantee of true expertise or ulterior motives on their behalf; but that's exactly what I expect from a magazine I'm paying for. If it had been for free, I would have said, OK, there's nothing wrong with a bit of biased review.

Rant over.

Cost: Will have to buy new and will almost certainly be a special order therefore not taking advantage of the suppliers bulk buying of standard 12L and 15L cylinders
Deprecation: When you come to sell (which you will) you will loose a fortune as there is no significant second hand market for big cylinders
Centre of gravity: Sheer bulk moves the centre of gravity further away from you which makes it less stable underwater and harder to carry out.
Safety: This is the big one. Carrying two cylinders is not just for the extra capacity it is to give you bailout options. If you loose one side you still have the other to get back to the surface. A large single gives you the gas to get into deep trouble but with not the redundancy to get out

Very true. My inital plan was to get one 15L 300bar tank, then another one down the path. What I'd like to ask is why sell? Maybe naive, but if you buy a brand new steel 15L, why sell it?

Another one (Category=stupid, so brace yourself) is:
Do you use 2 sets of tanks: one for air one for nitrox? And eventually the 3rd for heliox? (I'm not certified to use trimix, just air and nitrox, so for me its irrelevant, but was just currios).

I know air tanks can be cleaned for nitrox use, but do you actally do that, or just have separate tanks?

MattV

26-10-2010, 12:38

Of course they do, they just havnt been mentioned on here yet ;)

You were talking about your Zeagle Tech.

How about this one?
Seac Sub Pro Tech SWS BCD
(seller (e.g.): http://www.mikesdivestore.com/1594/Seac-Sub-Pro-Tech-SWS-BCD.html)

Would that take a twinset with manifold?

PeteM

26-10-2010, 12:48

I can see your point. However, I've never dived on a wing. My attachment to BCs comes from a day with really choppy seas when I floated on a really good BC for over an hour, until the boat finally saw us. Several reviews of wing BCs cautioned of the fact that they tend to push you face down (which is perfect under the water, but not so good on a choppy sea topside). Now, I'm a good swimmer, and in relatively good shape (except from my belly who seems to have a mind of its own and resists my running and gym assault :D), but I was quite tired after an hour of swimming against a mild current, and then trying to keep my head above water for another 70-80 mins in choppy water.

Maybe this is childish, and more experienced divers would laugh at the above story, but I'm not so sure I would. How do you find your wing BC? Are those reviews true, or just a load of BS to keep the market going for classical BCs?

I've never had a problem with it pushing me forward. I suspect that a lot of people have problems because they go for a huge wing that is far too big for the purpose. Part of the reason for earlier saying don't get one that is too big.

Very true. My inital plan was to get one 15L 300bar tank, then another one down the path. What I'd like to ask is why sell? Maybe naive, but if you buy a brand new steel 15L, why sell it?

If you've got a twinset will you use a single? If not why have one sitting in the garage?

Regarding 300bar, do some research first. I would NOT buy a 300bar cylinder. Too much hassle. It takes a lot longer to fill a 300bar, normally over night and even then you may not get a full cylinder. Some shops will refuse to blow it with nitrox or trimix, they are very heavy, and they suffer from most of the problems with even larger cylinders. Nigel H however has (http://www.nigelhewitt.co.uk/diving/rant/#300bar)written this as a more pro article.

Don't take this the wrong way but you seem fixated with taking lots of gas, my guess is therefore you are very new to diving and are going through gas at an alarming rate. That is classic newby reaction and going for big cylinders/high pressure cylinders/twinsets is pretty much exactly the wrong approach to the problem.

You end up carting around a lot of weight you don't need so by the time you actually get in the water you breathing hard, your trim and buoyancy therefore go out of the window, so you breath harder and it gets worse. The best solution is to accept that you are going to get short dives until you get experience and go diving lots and lots. Make sure your buoyancy is spot on and you are not over weighted (in my experience the majority of new divers are). As you relax more your buoyancy and trim get better which helps you relax more so it gets even better. It is a positive reinforcement circle. It took me about 80 dives to get to that point though.

Most reasonably experienced divers are limited by no stop times/deco limits on a 12L 232bar cylinder, a lot of new divers go down the "lets take loads of gas" then end up with an oversized cylinder which they never use.

Another one (Category=stupid, so brace yourself) is:
Do you use 2 sets of tanks: one for air one for nitrox? And eventually the 3rd for heliox? (I'm not certified to use trimix, just air and nitrox, so for me its irrelevant, but was just currios).

I know air tanks can be cleaned for nitrox use, but do you actally do that, or just have separate tanks?

No, one set of cylinders for everything and be careful where you get them filled. Some shops have sell air and clean air (does that make the other one dirty? if so do you really want it).

TerryH

26-10-2010, 12:54

You were talking about your Zeagle Tech.

How about this one?
Seac Sub Pro Tech SWS BCD
(seller (e.g.): http://www.mikesdivestore.com/1594/Seac-Sub-Pro-Tech-SWS-BCD.html)

Would that take a twinset with manifold?

TBH i'd say no.

It's a pseudo tech BC, stick a few D-rings on and call it pro-tech, the real
clue is in the lift. Hovering just around 18kg, that's comparable with a lot of
ordinary BC's, not exactly an improvement.

The Tech on the other hand has a standard Bladder thats about 30kg and you
can go even bigger. The difference is the bladder is seperate from the
harness. It's a similar wing as what you'd get in a wing/backplate, but
instead of the backplate you get a wraparound fabric harness that is more
akin to a BC.

If you want another alternative, have a look at the Dive Rite transpac with
a classic wing. Should start you off nicely and you can use the wing on a
standard backplate with harness at a later date, so it is expandable.

But ...............

If i'm being honest i'd go out and buy a cheap basic single BC, great for
plopping off RIB's and throwing in a case for abroad. No faff, swapping
the wing, messing up the rig set-up for twins.

Basic BC for a single + simple wing/BP/harness for twins.

MattV

26-10-2010, 13:43

Don't take this the wrong way but you seem fixated with taking lots of gas, my guess is therefore you are very new to diving and are going through gas at an alarming rate. That is classic newby reaction and going for big cylinders/high pressure cylinders/twinsets is pretty much exactly the wrong approach to the problem.

Yup, I'm pretty new. AOW/Nitrox/Deep/Drysuit/Night. Working my way to Rescue and hopefully to DM.

I'm not *extremely* bad at air consumption. I last about an hour on a standard Al80/3000psi. Considering that I'm 6ft3in and about 15st 8lb, I'm not a complete disaster (or at least I hope so) :D

What gets to me, is that I suck the nitrox down quicky; if I only had a bit more then I'd be able to stay the full non stop time. Hence my quest for larger tanks.

One more than one ocasion, I ended up at 500psi after 50 or so mins when the others (in much beter shape than me) were still around 1200! So I do admit my shortcommings as a newbie and I've never claimed otherwise :D!. Hence my questions on the forum.

On the other hand, I'm quite taken with the tech route. (I hope, by now I've convinced you that I'm not saying that coz I wanna sound cool) ;) I really likethe sport and like to get a bit deeper/longer. I'm particularly fascinated by wrecks and elusive lifeforms. So I thought investing in equipment that can be upgraded to the route I wish to take is a sensible thing to do.

You end up carting around a lot of weight you don't need so by the time you actually get in the water you breathing hard, your trim and buoyancy therefore go out of the window, so you breath harder and it gets worse. The best solution is to accept that you are going to get short dives until you get experience and go diving lots and lots. Make sure your buoyancy is spot on and you are not over weighted (in my experience the majority of new divers are). As you relax more your buoyancy and trim get better which helps you relax more so it gets even better. It is a positive reinforcement circle. It took me about 80 dives to get to that point though.

That is true, I tend to go overweighted. I used have difficulties keeping the safety stop, but no major issues now. Not very good (still) in a drysuit. But then you mention 80 dives - Im only at 26 (logged). :(

Still, I think I'm at the point where I need to get my own BC, and that's what I've been asking around :D

Most reasonably experienced divers are limited by no stop times/deco limits on a 12L 232bar cylinder, a lot of new divers go down the "lets take loads of gas" then end up with an oversized cylinder which they never use.

Ok, so you're saying that a standard BC and a 15L 232 tank would be enough for a long time from now. Actually, that is the best thing I've heard, and I thak you for that. I think I might be getting a bit ahead of myself in trying to plan for the very long run. It makes a lot of sense!

No, one set of cylinders for everything and be careful where you get them filled. Some shops have sell air and clean air (does that make the other one dirty? if so do you really want it).

Yup, you probably mean double filtered air. My question was, can you just refill a tank previously filled with air (clea) with nitrox?

Many thanks for your input, was really helpful!

MattV

26-10-2010, 13:52

Basic BC for a single + simple wing/BP/harness for twins.

Thanks, I think you're absolutely right. Besides (see above post) it might be a while until I'd need twins.

Ron MacRae

26-10-2010, 14:14

Ok, so you're saying that a standard BC and a 15L 232 tank would be enough for a long time from now. Actually, that is the best thing I've heard, and I thak you for that. I think I might be getting a bit ahead of myself in trying to plan for the very long run. It makes a lot of sense!

That's probably true for most people, it depends who you are diving with.

As you get more calm/confident/streamlined/economical in the water your consumption will get better over time and you won't be the first one ending the dive. It just happens so forget about it and go diving as much as possible.

Eventually you'll come to the point where, due to deeper & longer dives you can now do, you need a redundant gas supply and then you need to think single & pony or twinset. But even then you will probably keep your single as a twinset isn't always appropriate if diving off a small RHIB or from the shore.

Most twinset divers also dives single sometimes.

Ron.

Woz

26-10-2010, 16:20

I nailed twin 12s to a Buddy Commando for a while. The shoulder clips got a bit alarmingly creaky and the stainless bands had to be moved to a very low 7.75" spacing- I made a couple of custom mushroom nuts to stop them from digging into my back. The standard backplate also joined in on the alarming creaking.

You also had not a cat in hell's chance of reaching the valves as they were a long way off your back.

MattV

26-10-2010, 17:04

That's probably true for most people, it depends who you are diving with.

Awwww... there you've pointed towards a great truth. Been reading on Nigel Hewitt's page about how people wanna get pro just for the sake of it, or because they're pompous idiots (my paraphrasing). There's also a third factor: cliqueness. ;) If you're not at least divemaster you need to go play at the sand pit with the rest of the kids :).

I can see how someone with lots of experience wold get crossed that his buddy gulped down the air faster and cut the dive by 10 mins. But then, only few people derive joy out of teaching others :).

As you get more calm/confident/streamlined/economical in the water your consumption will get better over time and you won't be the first one ending the dive. It just happens so forget about it and go diving as much as possible.

... or I should go diving with complete noobs... :D

Funny how things are. This buddy of mine looks like Santa ;) but sometimes I feel like he's getting out of the water with more air than he got in :D. So it can't be overall fitness, as I can do 10Km in 45 mins, and it takes him that time just to get off his arse :D
It has to be the weighting... ;)

John Bantin

26-10-2010, 17:34

Woz

26-10-2010, 17:37

MattV

26-10-2010, 19:24

We have used the same Buddy Trimix BCs for our regular regulator tests since they were first produced. They are back-flotation jackets but have a plastic backpack identical to other Buddy BCs. We use them with twin 12-litre aluminum cylinders and identical 12-litre sling tanks. They have never let us down. I can see no reason why any other Buddy BC, provided it has sufficient maximum lift, should not be able to do the same. Last used in September, they wait in my cupboard for the next occasion.

Ok so today I had a chat with someone who runs a PADI dive centre. Basically all modern BCDs (Buddy and Scubapro in particular) can take twins (they even have holes into their backplate specifically for this purpose). He gave me the example of Scubapro T black, which can get you lots of lift (up to 30Kg in the XL variant) and also is very rugged. Pricewise, Scubapro and Buddy are roughly at the same level (new). Obviously since Scubapro is owned by the yanks we'll spit on it, but I'm gonna try one :D

I think potentially Al tanks are a very good idea for twin since they're lighter.

So thanks for the input. Like anything else, the more you look into it, the clearer the picture! (though I'm still not gonna get twins yet) :p

Ron MacRae

26-10-2010, 19:29

I think potentially Al tanks are a very good idea for twin since they're lighter.

Not sure why that would be a good idea. You just have to carry more lead. I deliberatly went the other way, twin 12x300s, so I wouldn't need any weights.

Ron.

Hickdive

26-10-2010, 20:12

He gave me the example of Scubapro T black, which can get you lots of lift (up to 30Kg in the XL variant) and also is very rugged.

Ah, but are YOU xl too? The xl version of the BCD may have sufficient buoyancy to support the twinset but it might slop around on you like a bell tent on a twiglet. Fortunately, you don't need huge amounts of buoyancy - play around with that link I posted earlier and you'll see that two cylinders with a full weight of 15kg do not require 30kg of lift.

I think potentially Al tanks are a very good idea for twin since they're lighter.

Are they? Aluminium is a lighter metal than steel but is also weaker - meaning you need more of it for the same strength. Again, have a look at that link I gave you and check out the weight of a Faber 12.2 litre steel cylinder against that of a Luxfer 12.2 litre aluminium one.

Out of the water an aluminium cylinder is heavier than the equivalent steel. BUT because the cylinder walls are thicker in an aluminium cylinder they displace much more water; so they're lighter in water. That means they're more awkward to carry about on the surface but, conversely, they need more lead to sink them . This isn't so bad and can be an advantage in a wetsuit but is a serious pain if you're wearing a drysuit.

Where aluminium cylinders score is as stage cylinders. With careful selection you can have a stage that is neutrally buoyant or only slightly negative through most of the dive and actually positively buoyant at the end. This means you don't need to adjust your weighting to allow for taking a stage cylinder or not and, if you somehow lose your stage, you can still control your buoyancy through the ascent.

So thanks for the input. Like anything else, the more you look into it, the clearer the picture! (though I'm still not gonna get twins yet) :p

If I were you I'd probably just buy a second-hand buddy commando. They're cheap as chips on eBay and extremely robust so there's not much to go wrong with them and, if something does break, AP valves can fix it for not a lot of money.

Stick a single 12 and a pony on it. That does most people for most dives. If you decide to move on to a twinset you'll be able to flog the commando and pony to help fund another 12, manifold, BP/W etc.

MattV

26-10-2010, 23:16

Ah, but are YOU xl too? The xl version of the BCD may have sufficient buoyancy to support the twinset but it might slop around on you like a bell tent on a twiglet.

Well, that's another b**ch. According to chest measurements, I'm on XL. Some BCs I've tried were fitting perfectly in XL size, others in L. I'm pretty broad, and as I said *reasonably* tall too (6ft3). Most instructors put me in XLs, but there are brands I fit snugly in L (all these things are highly adjustable tho, so minor diffs are a bit OTT).

That means they're more awkward to carry about on the surface but, conversely, they need more lead to sink them . This isn't so bad and can be an advantage in a wetsuit but is a serious pain if you're wearing a drysuit.

Umm... I see your point. I thought Al would be lighter, but after more reading I admit I was wrong. Now I remember when I got certified, I was actually told that resorts take Al tanks because they don't corrode that much (the exterior layer corrodes, then prevents deeper corrosion). So yeah, I can see your point now. Funny how we get swept away by preconception (because Aluminium (2560 - 2640 kg/m3) is lighter than Steel (7850 kg/m3). Never thought that same tanks would have different wall thickness, but they had to, otherwise Al would just buckle under stress. Damn, they should make them out of Titanium (at 4500kg/m3 they have 900MPa tensile strenght vs steel 660MPa). Probably would cost same as your car, but it would be the ultimate :D

If I were you I'd probably just buy a second-hand buddy commando. They're cheap as chips on eBay and extremely robust so there's not much to go wrong with them and, if something does break, AP valves can fix it for not a lot of money.

You know, everyone in this country pretty much reccomends Buddy commando. If you're in the States you 'must' haver Scubapro. If you're somewhere in South Europe I suppose you're a cretin if you don't have Cressi. I'm not gonna buy one without trying lots. Ive got lined up several to try on Thu. Don't get me wrong, I'm in no rush to buy. Besides, a friend of mine is gonna let me play in the pool with a buddy commando, several scubapros, a Seac and a Zeagle with different size tanks (i'm even gonna try the 10L/300bar one)

I'm gonna buy only after I dive with several variants (at least in the pool). I've done enough research, I've got my head pretty clear on what features I want.

Stick a single 12 and a pony on it. That does most people for most dives. If you decide to move on to a twinset you'll be able to flog the commando and pony to help fund another 12, manifold, BP/W etc.

This is a good sugestion, but I'm gonna stick to a single tank until I get my tech qualifications. After the intro course I'll see which way is for me.

Ta,
M

Andy Mason

27-10-2010, 05:17

Hi Matt,

I use a BP&W for all my diving (single/twins) and love it. Yes it is a bit 'techy' but in my experience a BP&W the way to go. I find diving the same BP&W for both singles and twins allows me to be familiar and comfortable with my kit (I dive twins only occasionally).

If you want a soft pack (BCD style) that can be modified to run both singles and twins then I support the recommendation earlier in this thread that you check out the DiveRite TransPac. This is an excellent solution for someone wanting to buy a BCD for single tanks that can also be modified to run twins and stages down the track. OMS, Oxycheq and Hollis have similar soft pack BCDs but I haven't dived them. These are very different to the more traditional style BCDs that often claim to be able to run twins - In my experience these often fail to deliver the stability of a BP&W or Transpac etc.

Re tanks, I like 12.2l steel Fabers as they are relatively light on the surface and remain negatively buoyant. 15l Fabers are great if you need a bit more gas. Personally I don't use 18l tanks as I'd run twins if my plan required that much gas (like an earlier contributor to this forum I'd expect to be planning for a deco dive anyway and would run twins for redundancy).

I also note you have done PADI AOW, Nitrox, Deep, Drysuit and Night courses and you've done 26 dives. Sounds like you've done a lot of training and will also learn lots by just doing more diving. Personally I find my BSAC branch a very worthwhile and rewarding way of diving and I would recommend it to you. There is a lot to be learned from BSAC that is not available from other agencies. And a lot to be gained from being part of branch and the broader BSAC community. I recommend it to you.

I hope all this is helpful to you.

Andy

John Bantin

27-10-2010, 08:56

Shut downs? Easy! Why put them on your back if you've only got two tanks?

Hickdive

27-10-2010, 09:03

You know, everyone in this country pretty much reccomends Buddy commando.

It's not that the Buddy is a particularly brilliant BCD. When I first tried one I had been used to an ABLJ and found the Commando was like swimming around with a wardrobe under each oxter. You will almost certainly find that the Scubapro is much more comfortable and streamlined.

However, the Buddy is built in the UK by a company that will sell you spares or carry out repairs for you as an individual without having to work through an LDS. The spare and repairs are generally cheap and AP valves are renowned for their customer service. Basically, you can always get a Buddy fixed - no matter what is wrong with it and it's built so robustly there's little to break in the first place.

So, if you want to save money until you can afford a twinset and wing then buying second-hand makes sense. If you're buying s/hand then Buddies are a cheap, safe bet.

ChristianG

27-10-2010, 10:05

I use a BP&W
Huh?

Neither acronymfinder (http://www.acronymfinder.com/) nor the BSAC's own version of it made me any the wiser. I probably (perhaps, possibly) know what it is but not as an acronym.

PeteM

27-10-2010, 11:02

Huh?

Neither acronymfinder (http://www.acronymfinder.com/) nor the BSAC's own version of it made me any the wiser. I probably (perhaps, possibly) know what it is but not as an acronym.

Back plate and wing

TerryH

27-10-2010, 11:32

If you want a soft pack (BCD style) that can be modified to run both singles and twins then I support the recommendation earlier in this thread that you check out the DiveRite TransPac. This is an excellent solution for someone wanting to buy a BCD for single tanks that can also be modified to run twins and stages down the track.

Just to add that as you are planning on getting to DM level and possible
work, the pro-world of scuba schools works on standard BC's'. Wing/BP is
a very niche part as far as that's concerned, so any system you buy needs
to at least look comparable to what your clients use.

That means a cheapo standard BC again or something like the transpac,
which although is a wing, looks from the front like a BC.

MattV

27-10-2010, 13:09

Hi Matt,

Re tanks, I like 12.2l steel Fabers as they are relatively light on the surface and remain negatively buoyant. 15l Fabers are great if you need a bit more gas. Personally I don't use 18l tanks as I'd run twins if my plan required that much gas (like an earlier contributor to this forum I'd expect to be planning for a deco dive anyway and would run twins for redundancy).

Andy

Thanks for the input, I thought 18L are a bit OTT. Was just a bit confused by different capacity standards (cubic foot) vs Liters x pressure. My mental arithmetic is pretty crap, so I equivalated the standard Aluminium 80 to 15L. I think I was wrong its actually more like 12. I'm still confused though. When I take over the world I'll scrap multiple measurement scales!!!<mad laugh> mad:

I also note you have done PADI AOW, Nitrox, Deep, Drysuit and Night courses and you've done 26 dives. Sounds like you've done a lot of training and will also learn lots by just doing more diving. Personally I find my BSAC branch a very worthwhile and rewarding way of diving and I would recommend it to you. There is a lot to be learned from BSAC that is not available from other agencies. And a lot to be gained from being part of branch and the broader BSAC community. I recommend it to you.

I hope all this is helpful to you.

Andy

Thanks for all the info Andy, was very helpful indeed. I actually like the training, and I wellcome an instructor who makes me do an exercise until I'm absolutely spot on. Unfortunately those days you get more of a superficial approach, I think mainly driven by the impulse to please the "client". I'm gonna go for the Rescue Diver course soon, Im not sure exactly when, but I plan to have that before March.

I personally like the PADI system as I'm quite busy with my day job. Most of my diving friends have trained with PADI (until Master Scuba Diver/DM) then TDI(not gone into the Instructor, etc). But they dive with BSAC. I intend to do the same. So if you tell me what's the name of your BSAC club, and an address (if you have a web page that'll be great), I'll have a look. I'm looking to join a club early next year (Feb/March) as I'm completely blocked at work until then. But I am seriously looking to join a club, and I will as soon as I find the right one.

Most people whinge about PADI clubs being a 'money making' enteprise, but I've come in contact with some BSAC ones which were more expensive in terms of membership fees, and offering very little (IMO) for that money. And, I dont' see why I need to pay a BSAC membership fee if I do not wish to train with them. Anyway, I do not know much abot BSAC policies, so I don't want to talk without further research. But as a general question (since you brought the subject up) is: Can you get all the way with PADI/TDI and just dive with BSAC without any official training with them?

MattV

27-10-2010, 13:13

However, the Buddy is built in the UK by a company that will sell you spares or carry out repairs for you as an individual without having to work through an LDS. The spare and repairs are generally cheap and AP valves are renowned for their customer service. Basically, you can always get a Buddy fixed - no matter what is wrong with it and it's built so robustly there's little to break in the first place.

Do they break down a lot? I mean, the dump balves and the inflator are pretty much the only tehnical bits in them. The rest is just wear & tear, isn't it?

Woz

27-10-2010, 13:39

But as a general question (since you brought the subject up) is: Can you get all the way with PADI/TDI and just dive with BSAC without any official training with them?Yes of course. Divers in our club from other agencies are welcome to dive with us. They have to join BSAC, join the club, fill out a medical form and that's it.

You only have to "crossover" to the BSAC system if you want to further your training. If you don't want to then just dive within the limit of your qualifications.

Some clubs don't even require BSAC membership but you have to show that you are adequately insured to the same level you get with membership. It's normally more expensive to do this individually anyway so you may as well join :)

Richard Whitcombe

27-10-2010, 22:40

My attachment to BCs comes from a day with really choppy seas when I floated on a really good BC for over an hour, until the boat finally saw us. Several reviews of wing BCs cautioned of the fact that they tend to push you face down

Its a myth spread by people without a clue. If you have a ridiculously oversized wing for a single tank and then ridiculously overfill it the thing COULD push you forward. Simple answer is don't use a ridiculously oversized wing and it cant happen!

How do you find your wing BC?

There is not a chance in hell id ever voluntarily dive in open water wearing a BC again. I dislike BCs because they arent totally secure, all move a bit, all crush to an extent with full, the pockets are pretty much unusable or when full, they're very cluttered with lots of things to break.
My wing has a harness perfectly adjusted to me. It doesn't move on my back at all. Ive got a waist band pocket that works perfectly. I can move all the D-rings. I have no clutter around the front of me. I can completely inflate it without it crushing me from the sides.

I would recommend ignoring all reviews in all published magazine. They all have an advertising budget to meet, all are superficial, lacking in detail, vague and in short, completely worthless. Real users are the best option.

Do you use 2 sets of tanks: one for air one for nitrox? And eventually the 3rd for heliox? (I'm not certified to use trimix, just air and nitrox, so for me its irrelevant, but was just currios).

No point, get 1 set of tanks, get them O2 cleaned, use them for all types of backgas. I use 1 set of twin 12s from air through to trimix.

Richard Whitcombe

27-10-2010, 22:45

I think potentially Al tanks are a very good idea for twin since they're lighter.

Not they're not. For the same capacity they're HEAVIER on land than the equivalent steel, physically bigger and most annoying of the lot, buoyant when low on gas meaning you need to wear even more lead to sink them.

Aluminium is good for stages but rubbish for back gas.

Hickdive

27-10-2010, 22:47

Do they break down a lot? I mean, the dump balves and the inflator are pretty much the only tehnical bits in them. The rest is just wear & tear, isn't it?

There's not much to break but but if you're trying to save the pennies by buying second hand you have to allow for the wear and tear the previous owner put in before you put in your own.

Woz

27-10-2010, 22:59

A 3000psi AL80 is about 11 litres. But you get more gas in a 232 bar 10L cylinder.
Blimming Yanks making the maths hard. Nearly as tricky as BSAC gas planning :)

Andy Mason

28-10-2010, 02:23

Hi again Matt,

I'm a member of the Brisbane Sub-Aqua Club in Australia, so that's not much good to you. You're most welcome to visit or join if you ever find yourself over here.

The BSAC Branch Finder can help you find a club closer to home:

http://www.bsac.com/page.asp?section=2164

In answer to your question about training with PADI/TDI and diving with BSAC - in my experience the answer is yes. One caveat here - I've only been a member for 2 years and am not a Branch Chairperson or Dive Officer and can only speak from my experience. Ok, so I joined my branch after training with other agencies. I found the process simple (just a BSAC induction talk) and the branch welcoming. I then dived with my branch to my existing qualifications. Later I decided to undertake some BSAC training (Dive Leader and Open Water Instructor). More recently I travelled to the Philipines with some friends from my branch and undertook a BSAC normoxic trimix course before putting that knowledge to use in the South China Sea. And at Easter we're off to the Great Barrier Reef (we've chartered a whole live-a-board!). So joining BSAC has been a fun and worthwhile experience for me - and diving to my other agency training was no problem.

Andy

Ron MacRae

28-10-2010, 09:00

There is not a chance in hell id ever voluntarily dive in open water wearing a BC again. I dislike BCs because they arent totally secure, all move a bit, all crush to an extent with full, the pockets are pretty much unusable or when full, they're very cluttered with lots of things to break.
My wing has a harness perfectly adjusted to me. It doesn't move on my back at all. Ive got a waist band pocket that works perfectly. I can move all the D-rings. I have no clutter around the front of me. I can completely inflate it without it crushing me from the sides.

I would recommend ignoring all reviews in all published magazine. They all have an advertising budget to meet, all are superficial, lacking in detail, vague and in short, completely worthless. Real users are the best option.

Agree 100%:)

Ron.