The Good, The Bad, The Ugly of Side Mount

[mulla]

The main reason why I got into SM is because I don't have to deal with the weight of doubles on land. Lifting in and out of cars, up and down stairs, climbing up ladders out of water etc (basically situations where a cart is not possible). I see a lot of people in BM doubles having to stand their reg up at the back of their wagon and then gear up, which is good "IF" you own a wagon. I don't. If there's no bench etc, I can always gear up with tanks standing on the ground and then stand up with back straight / one leg kneeling position.

The drawback I suppose for me would be getting used to things like switching regs, different gear configuration and difficulty in finding fellow SM divers locally to discuss issues and problems with. Planning to go into tech, you have added "problems" like finding out best place to keep your deco bottle etc.

As many have said before "ask 10 SM divers for their opinion and you'll get 11 answers". You will have to spend some time and money experimenting with different configuration and finding one you're comfortable with. Which I guess is not necessarily a bad thing if you enjoy it.

 

[BabyDuck]

for me the biggest con was the fiddly-ness of it. moving bands, moving weights, loops of bungie, no - ring bungies and chokers, sorenson swap, swap it back, oops - spgs are in the wrong place so i did something wrong, where the bloody hell is the inflater this time, on & on & on.

most of it is worked out now, more than a year later, and there are lots of big pros, but i don't think i'm still as comfy & satisfied with my muscle memory as i was in bm.

 

[billgraham]

Worst case scenarios (all pretty unlikely), a manifold failure, or an inability to shut down the correct tank with a problem in manifolded doubles and you could conceivably lose all your gas. Curt Bowen did an article in ADM some years back with charts about how fast you could drain a tank with a blown hose at various depths that was pretty frightening. If you follow the rule of thirds in sidemount, you've (theoretically anyway) got enough gas if you lose one cylinder completely. I think the odds of not being able to do a valve shut down are infinitely greater than having a manifold failure. Backmounted doubles are a good safe system and most people dive them. I personally haven't found any cons to sidemount, and the pros for cave and wreck diving are obvious.

 

[PfcAJ]

if you cant shut your valves down in any configuration, you're asking for trouble. Be it SM, BM, single tank, monkey diving, rebreather, or anything else you can cook up.

 

[Dive-aholic]

There's also a question of which hose to donate. Typically, with BM doubles, you just give up the one in your mouth. Certain SM configs do no then themselves to this. Also, I see lots of SM guys putting the longhose on the right tank. This is the tank that rolls OFF with contact in the bottom (valve knobs out). There are multiple accounts of SM rolloffs on CaveDiver.net. This could be bad, as well, especially if you're taking SM into smaller areas.

It would help if you had any sidemount experience before commenting on it. I've had a total of 2 roll offs since cave diving, both in sidemount, and both my left cylinder. And it's been a few years since the last one. With the cylinders properly positioned a roll off is almost impossible on either cylinder.

 

[billgraham]

if you cant shut your valves down in any configuration, you're asking for trouble. Be it SM, BM, single tank, monkey diving, rebreather, or anything else you can cook up.

Nonetheless, a lot of people can't reach them easily in drysuits, I notice. I've also seen problems involving tanks filled with the isolator closed, not discovered until the diver is on the bottom. That's kind of a scary one because if you open the isolator, you now have a mystery mix.

 

[PfcAJ]

It would help if you had any sidemount experience before commenting on it. I've had a total of 2 roll offs since cave diving, both in sidemount, and both my left cylinder. And it's been a few years since the last one. With the cylinders properly positioned a roll off is almost impossible on either cylinder.

Uh huh. It can't happen to you because they're 'properly positioned'. So apparently it CAN happen, since it happened to you TWICE, and its happened to other people, as well.

This is the same argument that people say about rolloffs in backmount. "Hurr, I've never had one, been diving for years! Just don't hit the ceiling!"

Its OK to dive SM, but at least recognize the drawbacks. Brushing them under the rug doesn't help anyone.

---------- Post added ----------

Nonetheless, a lot of people can't reach them easily in drysuits, I notice. I've also seen problems involving tanks filled with the isolator closed, not discovered until the diver is on the bottom. That's kind of a scary one because if you open the isolator, you now have a mystery mix.

Absolutely. The isolator needs to be checked often, and you've got to be able to reach those valves. If you don't do pre-dive checks (including checking your valves) and just hop in the water, there's not much hope in any configuration, either.

 

[markmantei]

for me the biggest con was the fiddly-ness of it. moving bands, moving weights, loops of bungie, no - ring bungies and chokers, sorenson swap, swap it back, oops - spgs are in the wrong place so i did something wrong, where the bloody hell is the inflater this time, on & on & on.

most of it is worked out now, more than a year later, and there are lots of big pros, but i don't think i'm still as comfy & satisfied with my muscle memory as i was in bm.

Couldn't agree more. I have am just completing my switch to sidemount, and there was a lot more "adjustment" time than I envisioned when starting out, basically after every pool session or dive I was tweaking one thing or another that I didn't like, or could be done better (hose routing, mounting options for tanks, method for securing long hose, weight mounting, etc, etc). Also, things are just not where you are used to them being in BM singles, and as someone who could do just about any underwater gear adjustments, doffing, donning etc. completely blind effortlessly, that level of instantaneous gear change was frustrating. It demands a real adjustment period. I had to fight through the attitude of, "screw it I'm not having fun I'll just go back to bm". Now ~10 pool and easy OW dives later, I am glad I did. I am just about done with the major adjustments, and feel much more comfortable in the water.

Advantages, at least for me were:
-Easier to handle one tank at a time climbing down a rock face for a particular local dive site entry than heavy bm doubles.
-Easier to do valve shutdowns in a drysuit
-Easy transition of tanks between single tank bm and sidemount
-Easy to utilize the redundency sm offers on vacation dives

Have fun and dive safe!

 

[Adobo]

Nonetheless, a lot of people can't reach them easily in drysuits, I notice. I've also seen problems involving tanks filled with the isolator closed, not discovered until the diver is on the bottom. That's kind of a scary one because if you open the isolator, you now have a mystery mix.

So... if you have an ill fitting drysuit that restricts your movement (and similarly, if you have proper fitting exposure suits but have bad flexibility for whatever reason) or are prone to leaving the dive shop without knowing what is in your tanks + not checking the valve/isolator status before jumping in the water then sidemount might be for you. Is that right?

Having good flexibility and a properly fitting exposure suit has benefits well beyond being able to shut down valves. And jumping in the water without knowing what is in your tanks + not knowing the status of your valves/isolator before jumping in the water is pretty much abject stupidity, wouldn't you agree? Why wouldn't we advocate fixing these items independent of gear configuration?

 

[TSandM]

I guess you could say that there are certain errors that are far more possible in one configuration than in the other. You DO have to practice valve shutdowns in backmount, to be able to do them fast enough to make the setup useful. On the other hand, there is a story on the CDF about someone who wasn't able to identify and solve his own leak in SIDEMOUNT, so it isn't a panacea for valve problems.