Looking to start diving in sidemount or doubles. Which one first?
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Mike1967
Contributor
I do not really think that a course is required for using reasonably-sized twins in standard back mounting. When I started diving, a 10l+10l twin (steel) or 9l+9l (alu) were the standard, and when some years later I switched to a single 15 litres (at higher pressure), there was substantially no difference, as weight and air capacity were the same.
Please note that here in Italy also single tanks have twin valves, and the norm was always to use two independent first stages. This, at least, before the DIN mounting became common.
Given the same volume, what's the difference between a twin set and a single? The twin set is easier, less drag, more balanced. You get used to it during the first dive: as said, I do not see the need for a specific course for it...
Side mount is another story: first of all, air is now segregated in two independent reservoirs, instead of one, and you need to understand how to manage this safely. Each of them has a single reg, so in case of failure you loose half of your air (or more, if the other one is already at low pressure). Trim is very different: potentially better, but you need to get used to it. Same for drag: potentially better, but only if you manage to master the proper alignment of your equipment.
Also some part of the equipment will need to be modified, so here you face some significant upfront costs.
In conclusion, as many have already suggested, start with back-mounted twins (of reasonable size, no more than 20 liters total): it will be easy, fast and cheap. And you will get only benefits, no drawbacks.
After this, you will evaluate side mounting, which has some trade-offs, and results in a net benefit only under heavy "tech" circumstances. For rec diving (even with light deco) I think the drawbacks of side mounting do not compensate yet the benefits, but on this everyone has his own ideas.
Please note that here in Italy also single tanks have twin valves, and the norm was always to use two independent first stages. This, at least, before the DIN mounting became common.
Given the same volume, what's the difference between a twin set and a single? The twin set is easier, less drag, more balanced. You get used to it during the first dive: as said, I do not see the need for a specific course for it...
Side mount is another story: first of all, air is now segregated in two independent reservoirs, instead of one, and you need to understand how to manage this safely. Each of them has a single reg, so in case of failure you loose half of your air (or more, if the other one is already at low pressure). Trim is very different: potentially better, but you need to get used to it. Same for drag: potentially better, but only if you manage to master the proper alignment of your equipment.
Also some part of the equipment will need to be modified, so here you face some significant upfront costs.
In conclusion, as many have already suggested, start with back-mounted twins (of reasonable size, no more than 20 liters total): it will be easy, fast and cheap. And you will get only benefits, no drawbacks.
After this, you will evaluate side mounting, which has some trade-offs, and results in a net benefit only under heavy "tech" circumstances. For rec diving (even with light deco) I think the drawbacks of side mounting do not compensate yet the benefits, but on this everyone has his own ideas.
Mike1967
Contributor
Your name suits you lol
W W Meixner
Banned
SW...
I think you need a little self help here...before anyone's opinions are of any benefit...
Why do you want to switch from a single to a double configuration in the first place...
Extended range can easily be accomplished with larger single cylinders...HP steel 100's/117's/120's/133's/149's...
If all you're looking for is ''curb appeal''...save your money...as well as the cost of the additional gear...you need to fully buy into the learning curves...and you need to be able to comfortably handle the additional task loading for the conditions you're going to be regularly exposed to...
If you are seriously looking at double configurations for any reasons that seem to you to have important advancement benefits...make arrangements with a good local tech shop...who has regular pool access...and try both configurations...with the accompaniment of an instructor...ask all the questions...and satisfy yourself with the answers of a qualified professional...
From a personal perspective...if you're planning on ocean charters...whose operators use boats with high sided hulls...like re-purposed crew boats...and boats that use ''Christmas Tree ladders''...''side-mount'' would not be my choice...
Consider carefully first...spend money later...
W.M...
broncobowsher
Contributor
Both options are good, and bad.
Until you start a tank farm sidemount is nice as you can do it with minimal tanks. Use what you have now. Any rental tanks can be setup as well. With doubles you have a set of doubles. Have to completely empty them to split them back into singles if you want to do any regular diving. I know people who just do the simple recreationally dives on doubles, just don't change tanks between dives. That works, keeps you practiced out in doubles, but adds weight on land along with bulk.
I don't find sidemount off a boat that difficult. Narrow boat gates can make for an interesting sideways giant stride entrance. I've done a fair bit of sidemount. It does get the monkey off your back that a big set of doubles can create. But sidemount can also be fussy about getting everything to behave. I did a lot of dives playing with lengths of chokers, mounting positions, etc. Backmount does take the win for easier to setup. Still some adjustments but not nearly as many.
Baby doubles is something I have to admit I have never tried. Heard about them. Makes sense, but a little pricy with minimal gains in air.
You mention future plans. What are the long term plans. Not 6 months, more like 6 years.
My quick thoughts. Since you have a pair of tanks right now and still looks like you will be doing single tank as well. Sidemount is a quick and fairly cheap way of stretching your current gear with minimal investment. You state you plan to add the other method later, that would be another pair of tanks (so you can keep your existing tanks for single tank diving) and a little more gear.
Since you are diving wet, sidemount is probably a little better as well. Steel doubles in a wetsuit can get sketchy. Sidemount would let you throw away an anchor and still keep some air.
Go sidemount. And keep an eye out for a good set of used doubles for later.
What do I dive? I still own the regs off a sidemount setup but nothing else. Dive a rebreather. Once you start looking at a bottle of Helium it is the only thing that makes sense. I do own a tank farm. Every dive cylinder I bought I still own. Use them all even if in different roles. My AL40 deco bottle is now my small bailout bottle, same for the AL80s. The 100s are drive gas for the booster or clean air from the dive shop for home blending. Took 20 years to get to this point. But it is a good place to finally be at.
Until you start a tank farm sidemount is nice as you can do it with minimal tanks. Use what you have now. Any rental tanks can be setup as well. With doubles you have a set of doubles. Have to completely empty them to split them back into singles if you want to do any regular diving. I know people who just do the simple recreationally dives on doubles, just don't change tanks between dives. That works, keeps you practiced out in doubles, but adds weight on land along with bulk.
I don't find sidemount off a boat that difficult. Narrow boat gates can make for an interesting sideways giant stride entrance. I've done a fair bit of sidemount. It does get the monkey off your back that a big set of doubles can create. But sidemount can also be fussy about getting everything to behave. I did a lot of dives playing with lengths of chokers, mounting positions, etc. Backmount does take the win for easier to setup. Still some adjustments but not nearly as many.
Baby doubles is something I have to admit I have never tried. Heard about them. Makes sense, but a little pricy with minimal gains in air.
You mention future plans. What are the long term plans. Not 6 months, more like 6 years.
My quick thoughts. Since you have a pair of tanks right now and still looks like you will be doing single tank as well. Sidemount is a quick and fairly cheap way of stretching your current gear with minimal investment. You state you plan to add the other method later, that would be another pair of tanks (so you can keep your existing tanks for single tank diving) and a little more gear.
Since you are diving wet, sidemount is probably a little better as well. Steel doubles in a wetsuit can get sketchy. Sidemount would let you throw away an anchor and still keep some air.
Go sidemount. And keep an eye out for a good set of used doubles for later.
What do I dive? I still own the regs off a sidemount setup but nothing else. Dive a rebreather. Once you start looking at a bottle of Helium it is the only thing that makes sense. I do own a tank farm. Every dive cylinder I bought I still own. Use them all even if in different roles. My AL40 deco bottle is now my small bailout bottle, same for the AL80s. The 100s are drive gas for the booster or clean air from the dive shop for home blending. Took 20 years to get to this point. But it is a good place to finally be at.
W W Meixner
Banned
BB...
All good points...but nothing beats...taking the time trying...before spending the money buying...
As far as cylinder collecting...at some point...annual service costs/actual use/practicality far out-strip bragging rights and ''perceived need''...
W.M...
MichaelMc
Working toward Cenotes
Baby backmount doubles is more about redundancy than more air. It's a compact unit vs a pony. Nice for solo. Plus to play lightly in doubles land. Baby sidemount doubles is the same, just more flexible in the water but less compact. Both are about sane weights across the beach.
For sidemount, I think the task loading may be overblown. There are more dive setup tasks, like hooking tanks up. One more dive maintenance task, switching sides a few times during the dive. But likely fewer emergency tasks compared to a manifolded twin set; if one reg dies switch to the other and ascend if OW. If not OW, switch, feather, etc. Cave etc are their own story.
For just getting the tanks in the water with you, the sidemount learning curve is more, and all about tank handling and getting them set just right for you. A class in person, one of the video ones during our lockdown would get you set well. I read the whole sidemount forum and what it referred to, watched on-line videos, and puttered about in the ocean on days it was a lake, with tiny tanks to make it easier.
For just a bigger wider tank, backmount is way easier: doubles, a wing, maybe some hose changes, then strap it on like before.
Sidemount valve drills are not hard, swapping a reg in real need is even simpler, its something you do at least twice every dive, though not rushed. Re-stowing the long hose after buddy OOA drills is the hard bit. Backmount valve dills involve more, and are essential for that redundancy.
The tanks take up your sides, so they are not as clean that way as back-mount, but you are more flexible in the water.
From reading, sidemount tops out on total sensible volume before backmount does. Depends on how much gas you need. And why didn't you switch to a CCR by then?
Sidemount uses any tank (though not as easily depending on the valves), doubles not.
I wanted redundancy. Doubles involved a new wing. A sidemount rig was about the same cost as a wing and promised more freedom in the water and on travel. I think it payed off.
Definitely try each if you can.
For sidemount, I think the task loading may be overblown. There are more dive setup tasks, like hooking tanks up. One more dive maintenance task, switching sides a few times during the dive. But likely fewer emergency tasks compared to a manifolded twin set; if one reg dies switch to the other and ascend if OW. If not OW, switch, feather, etc. Cave etc are their own story.
For just getting the tanks in the water with you, the sidemount learning curve is more, and all about tank handling and getting them set just right for you. A class in person, one of the video ones during our lockdown would get you set well. I read the whole sidemount forum and what it referred to, watched on-line videos, and puttered about in the ocean on days it was a lake, with tiny tanks to make it easier.
For just a bigger wider tank, backmount is way easier: doubles, a wing, maybe some hose changes, then strap it on like before.
Sidemount valve drills are not hard, swapping a reg in real need is even simpler, its something you do at least twice every dive, though not rushed. Re-stowing the long hose after buddy OOA drills is the hard bit. Backmount valve dills involve more, and are essential for that redundancy.
The tanks take up your sides, so they are not as clean that way as back-mount, but you are more flexible in the water.
From reading, sidemount tops out on total sensible volume before backmount does. Depends on how much gas you need. And why didn't you switch to a CCR by then?
Sidemount uses any tank (though not as easily depending on the valves), doubles not.
I wanted redundancy. Doubles involved a new wing. A sidemount rig was about the same cost as a wing and promised more freedom in the water and on travel. I think it payed off.
Definitely try each if you can.
My personal experience was that backmount doubles was nearly zero learning curve. If you already have a handle on buoyancy and trim in single tank, then just practice valve drills for a while and you’ll be fine. Sidemount takes longer to get set up correctly, but diving it is fairly intuitive as far as valve drills and checking air. Its mostly a game of using air equally from both tanks. Fwiw i prefer sidemount for recreational dives or even tec dives that require back gas and just an al40 deco bottle. For bigger dives that need multiple stages and such, it only makes since to use the real-estate on your back.
Also a note on benefits after reading previous posts. true redundancy is gained with sidemount, offering safer diving practices. If a post fails with doubles you have a time sensitive period to actively recognize and isolate the problem before you lose ALL your gas. In sidemount you can still shut off a post, but if you dont in time, you will still only lose HALF your gas.
Also a note on benefits after reading previous posts. true redundancy is gained with sidemount, offering safer diving practices. If a post fails with doubles you have a time sensitive period to actively recognize and isolate the problem before you lose ALL your gas. In sidemount you can still shut off a post, but if you dont in time, you will still only lose HALF your gas.
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