Single or Dual bladder

I am just getting into sidemount and I am planning on taking a course in a few weeks. I was looking at purchasing the Hollis SMS 100 and noticed it come in single or dual bladders. I am currently diving a bp/w and am used to the single bladder. Is one better than the other?

Cheers

Orion

I have a dual bladder nomad xt if your intrested.

Thanks but I currently live in Bonaire and shipping here is a pain. I am ordering it through a dive shop and picking it up at a dive show in a few weeks. Do you prefer single, dual, no preference?

Some people will argue different ways but for me.

Wetsuit: Dual
Drysuit: Single or Dual

Its always nice to have two forms of bouyancy when things hit the fan, espically if your doing decompression diving.

orion612004:

I am just getting into sidemount and I am planning on taking a course in a few weeks. I was looking at purchasing the Hollis SMS 100 and noticed it come in single or dual bladders. I am currently diving a bp/w and am used to the single bladder. Is one better than the other?
Orion

Click to expand...

A very good question. And opinions differ. And, the answer is probably, 'It depends.' I was taught, and practiced for a long time, the concept of redundant buoyancy when diving doubles (BM). I would dive double steels with my drysuit for redundant buoyancy, or a dual bladder wing if diving wet - essentially what superspeed mentions. So, when I moved to SM, I carried that with me. However, there are some very experienced divers on SB who argue, with intelligence and logic, that you should not dive a rig that would make you rely on redundant buoyancy. If you can't swim it up, you shouldn't be diving it. If you are SM diving AL80s, chances are you can swim them up. Chances are you could even do that with HP 100s. But, if you are diving heavier steels, what are your options? A dual bladder BCD is one. The other is, if you have to, ditch one of the two bottles.

So, it is hard to answer the question, 'Is one better than the other?' because there is not one and only one answer. Rather, one is different than the other. If I was diving in Bonaire, and planning recreational SM dives, and was going to be using the ubiquitous AL80s found there, I wouldn't feel the need for a dual bladder. But, that is just me. I have taken a dual bladder Nomad with me before on trips to Bonaire, but I have also dove single bladder wings with SM double 80s on Bonaire, and that is my preferred approach.

Dual (redundant) bladder is a good option if you plan to progress into technical sidemount (3+ cylinder) diving and won't be using a drysuit. Such redundancy is a requirement for several agencies. As Colliam7 mentioned; there are other ways to do it (balanced rig), but you can't evade agency standards in training.

For recreational/open-water/no-deco sidemount, it's probably over-kill. Just make sure you dive appropriate cylinders for your exposure suit type. Al80's shouldn't cause any problems for a warm-water wetsuit diver.

A few questions.

What type of diving are you planning on doing?
What cylinders will you be using?
What exposure protection are you using?

Dual bladder does have it's own draw backs, the main one being that its another thing to check, service, etc and make sure it's working. I doubt most people really check the second bladder until they need it. Then there's the extra hose routing, and clutter associated with it.

So how is a bladder going to go wrong? Worst case, it could split because it gets over pressured. When's that likely to happen? When you jump off the boat. So make sure you give your over pressure valves a look every so often, and try not to inflate your bladder so it's ready to burst when you jump in. What else? Leaks, either from valves or just a hole. Well in this case, it's annoying, and you should probably call the dive, but it's not going to stop you getting out safely. It just might mean that you need to keep the air in one part of the bladder, or you have to top it up more often.

So for me, the key is not being massively negative at any point, which you shouldn't be anyway. That way, even if you lose it completely you're not going to sink like a stone. And realise that wing failures happen at the start of a dive, because of jumping in, or because you haven't checked it can hold pressure, so you should never be too far from help. Once on a dive, I don't know how you'd put a hole in a wing.

Obviously, a balanced rig would be the first choice. That said, I went with the dual bladder so the capability would be there. I felt I'd rather orally inflate 2d bladder than deploy a reel and bag. I mostly shore dive Bonaire and can see myself throwin' on a 5 mil wetsuit and renting two Steel 100's for a massively long light tec sidemount dive down around a 100 or so.....I know, just add an aluminum stage...no thanks, I'd rather just move two tanks on an iron shore entry in my old age.....I'm pretty sure I'll be hearing something about substituting equipment for skills on this but I just don't trust the reel and bag routine....sorry....