Question Sidemount or backmount doubles?

[rddvet]

You are quite wrong there. Lots of us who dive SM do so because of physical issues. My knees couldn’t take the weight of doubles.

OP, unless you have physical issues that would be aggravated by the weight of doubles/doing valve drills, go for doubles. They’re definitely easier on boats. If no boat diving, that opens up your options.

I intentionally didn't bring up physical limitation because its a very small percentage who have such limitations. And as was said above, alot of those issues aren't physical they're fitment of your gear. When I first learned doubles I couldn't do a valve drill and swore it was poor shoulder mobility. It was 100% purely technique and less than ideal bp/w and doubles set up

 

[rddvet]

# 1 SM dives way easier and more stable than backmount and

#2 no more pesky valve drills

#3When you're planning the next step aka tech diving, think about rebreathers. No need to haul all those tanks, just enough gas to get back up in case of trouble.

I numbered above.

1) for many years I thought sm was way more stable. If you are properly setup in doubles, you will be just as stable. It took me a long time to realize I was wrong in my thinking

2) You still need to do a valve drill and even an s-drill. They're just different. Sure you can see your valves, but you still need to know how to address the potential issues as well as how to exit on a bad valve via feathering

3) I don't know why this buy a rebreather phallacy so that you don't need all the tanks exist. Before I was ccr certified I thought the same thing because I heard it so much. It is very false. In reality, you need to plan your gas so that you can surface/exit if you lose your rebreather at the furthest point of penetration or depth. That typically means carrying similar volumes and types of gases as in oc. Having to carry just as much gas was the biggest shocker I learned in ccr training

 

[rddvet]

Thanks for all the opinions so far. In terms of availability abroad (when not wanting to fly in my own tanks), any big differences there?

You can find single al80s pretty much anywhere in the world. That is one benefit to sm. You can't always find doubles everywhere. But to counter that point, there are more and more boats banning sm divers for simple ow dives because they take up more space, tend to be more of a hassle to deal with, and the number of horrible sm divers that annoy captains are increasing.
So pros and cons, but go bm first.

 

[Tracy]

I am of the opinion, it depends. Doubles are easier to learn and dive. They are also heavy and can't really be broken down to move easier out of the water.
On a boat, sidemount is a cluster, there are a few that do it well, but even they take longer to get geared up and off the boat.
Sidemount is a useful tool, it allows you to go tech diving in places that you can't with BM doubles, there are many many places in the world where finding a rental set of doubles just isn't going to happen, but I can grab two AL80s just about anywhere with water.
My go to preference is doubles unless the dive or conditions warrant SM.

 

[Celt]

I moved from back mounted 12ltr twins to side mounted but the only advantage I found was it was less weight to handle, if I was diving 7ltrs twins I’d still back mount as it’s less fussy. See if you can try side mount before spending a lot of money,

 

[Cheizz]

I moved from back mounted 12ltr twins to side mounted but the only advantage I found was it was less weight to handle, if I was diving 7ltrs twins I’d still back mount as it’s less fussy. See if you can try side mount before spending a lot of money,

A try-out is available without having to invest in personal gear. Even a few tries if I wanted to. That goes for backmount as well, by the way. Whatever I do, I will try out first.

 

[broncobowsher]

I knew my plan was to get a rebreather eventually. Had a deep thought and figured where I wanted to be at in my diving. Learned (poorly) back mounted doubles. Had some people I dived with who did sidemount. I think good instruction and backmount is better most of the time. But some extent, travel is easier with sidemount, you just pick up a pair of tanks anywhere and you are off. You are not trying to rent a set of doubles anywhere.

Now the can of worms is getting opened. Suddenly you are getting into planned deco really easy. The added time, even if not deep, gets you. So you are next taking Advanced Nitrox and Deco Procedures so you can now use the added time the doubles just got you. Deco on air sucks, so you find yourself with a little AL40 of rich O2 to burn off the deco time.

Shortly after you start looking at rebreathers. Dive them recreationally and that AL40 is suddenly a bail out. Nice Nitrox blend the whole dive. Now you go deeper and Helium is a manageable expense with a rebreather. It's just another bail out bottle...

Having had all that. I should have spent more time with a better instructor on back mounted doubles in the beginning. Even with my less than stellar back, just used doubles and maybe played with sidemount. Sidemount can be nice when dialed in perfect, but that perfect dial in is not easy to come by. I can remember doing a dive and thinking I had it dialed in, took the gear off and put it back on, fighting it again. WTF! For the most part, throw backmount together and if it is close, it is happy. Much less sensitive to being a little off.

Unless you find a good logistics reason for sidemount, just start off with a set of doubles. If you haven't already done so, take a nitrox class.

 

[Wibble]

I intentionally didn't bring up physical limitation because its a very small percentage who have such limitations. And as was said above, alot of those issues aren't physical they're fitment of your gear. When I first learned doubles I couldn't do a valve drill and swore it was poor shoulder mobility. It was 100% purely technique and less than ideal bp/w and doubles set up

Reaching back and over your shoulder is a really hard thing to do and is easily impossible if you've got shoulder problems be that from an accident, congenital problems or age. Conversely reaching forwards to twiddle a sidemount valve near your chest is easy for virtually everyone.

Proof: have you ever had a valve jam on backmount that required you to get someone else to turn the knob because you don't have the purchase...? I have.

Sidemount however is right in front of you and you can pull the cylinder forward or unclip the bottom clip and really wrench the valve if necessary. You can even reseat the valve if it's leaking and you could even remove the regulator in extremis.

Backmount is a royal pain in the backside for any of that. You can barely reach the damn valves and need to do constant practice to do shutdowns. It's just plain horrible in comparison with the ease of sidemount.

So, for all your backmount practice -- beloved of the followers of DIR -- you need a little more practice to kit up in sidemount. Not a lot of effort required, just learning how to throw on the harness, attach the cylinders in sequence, breathe, and jump in. All that tosh about sidemounters being wider is just nonsense -- it's no worse than someone carrying deco/bailout stages.

But to counter that point, there are more and more boats banning sm divers for simple ow dives because they take up more space, tend to be more of a hassle to deal with, and the number of horrible sm divers that annoy captains are increasing.

Struth. Obviously miserable skippers who don't want customers.

Most of the sidemount divers I've seen are what we call "competent". It's like generalising that all backmount people are useless, or rebreather divers being plonkers.


Anyway, sidemount's great as the kit's more separate than the mono-lump of backmount. Sidemount's definitely better for people who have problems carrying the kit, especially up steps (our tidal range is 6m/18ft and climbing up a steep gangway is hard work. Climbing up a hill or over a shingle beach is a serious undertaking -- backmounted 12's/80s weighing in at over 50kg/110pounds plus.

Oh, and sidemount's an absolute delight in the water with superb trim. Backmount has that damn great keel weight on your back; turn sideways and you're over, same with head down as you can invert. Sidemount you can swim at just about any angle, even sideways, on your back, face down...

All my primary cylinders are steel, especially sidemount. The floaty ali80's need loads more lead to sink them.

There's one disadvantage of sidemount and that's mounting stages. One deco stage is OK, two are difficult, but doable with a little practice. Will concede that backmount and backmounted CCR are far easier with lots of stages simply because the stage space isn't taken up by the sidemount cylinders. Whilst the likes of Steve Martin demos 4 stages, it's hard! 4 stages on backmount is just two either side (unless you're a DIR proponent then you'll mess around with all on one side and dog leads...).

 

[Wibble]

The vast majority of "I can't do a valve drill" is a fit issue. Yes, there can be physical impairments, such as those that result in your inability to get onto a boat with a single tank, but SM still shouldn't be the primary system for most people.

Strongly disagree.

Reaching back to do a valve drill is very hard for most people and needs a lot of practice to get the knack of doing a valve drill. It also requires constant refreshing practice. Good example is you've jumped in and not turned your gas on (stupid thing, but happens in the real world). Sod doing it for real when you're in a panic because you can't breathe and you can't reach the valve to give it a good turn. Sidemount or bailout is really simple: it's in front of you and you can grab that knob to really turn it.

Sidemount's a great system and should be the primary system for people who want to use it as an alternative to the sub-optimal backmount system. It's more reliable than backmount which still has that manifold as a single point of failure.

 

[Cheizz]

Obviously, both backmount doubles or sidemount would require an investment, both in money and in time/practice. I would need proper and continuous training in either to really get the hang of it. That is not something that scares me or anything, nor is that something that differentiates the two. There are quite a few steps to take in between my current skill-set and diving with doubles properly, confidently. Not a problem.

Some boats ban sidemount, you say. On the other hand, getting back-mounted doubles anywhere abroad seems more difficult than two separate tanks for shore dives for example. If liveaboards ban double tank diving altogether, I'll just bring my single tank set-up.

Since training is a factor whichever way I choose to go, the downsides of sidemount seem to counter the upsides of backmounted doubles and vice versa. I will be able to try both out. I have the feeling that my experience with that (and yes, that includes a proper fitting of the sidemount harness, training, etc.) will hopefully give me my own opinion on what it feels like in the water.