Where do you prefer to mount your deco tanks

[Remy B.]

In the case of diving with 6 or more tanks, I see everybody mounting their deco tanks in the front.

But is this really practical ?

If you are deep do you not want complete visual and fast direct access to your bottom tanks, meaning that they shall be as reachable as possible in case of free flow and to check quickly pressure, your deco tanks are with the valve closed and you will need them only at ascend at 21m and 9m, is it not more logical that they are all the way on your sides and not on the front, or in case of 6 or 7 tanks in the case you have 4 bottom tanks and 3 deco tanks to have two bottoms on the sides, decos and then the other two bottom tanks in front of you for ready access.

 

[RainPilot]

I personally don’t dive more than four tanks. Even then it’s a bit of a PITA at times. All my Tech SM friends limit their OW sidemount to around 70m ie 4 tanks. Deeper than that they all go to BM.

 

[tomfcrist]

There’s nothing practical about a dive requiring sidemount doubles, 2 bottom stages and 2 or 3 deco tanks unless you are in a cave.

 

[Remy B.]

There’s nothing practical about a dive requiring sidemount doubles, 2 bottom stages and 2 or 3 deco tanks unless you are in a cave.

or a very deep wreck, with small tanks like I do.

 

[northernone]

or a very deep wreck, with small tanks like I do.

6 is a mess. Back gas is backgas, I'm happy to keep it there, with proper doubles training it's not a bad place to have cylinders.

There is little practical need to have them in front, my planning doesn't require underwater regulator rebuilding or valve servicing. I've fixed a blown hp oring underwater before but it was for convenience. Proper gas planning makes underwater equipment service unnecessary.

Am I understanding correctly you're doing wreck penetration where you need smaller diameter tanks to fit a hole? No mount, pushing 6 tanks ahead of you?

I am having trouble imaging the situation where this is the best solution outside of staging bottles in a cave.

When I've dove 6 tanks it was cumbersome and I did it single gas. No switching.

A pair of cave filled lp131s and a couple AL80s give me all the gas I need. More, my rebreather is the right tool for the job.

Cameron

 

[JohnnyC]

6 tanks with a set of twins is manageable. 6 in sidemount is just awkward. It sucks. If I need 4 stages plus backgas in sidemount in a cave, I'm doing setup dives. It's a pain in the ass otherwise and doesn't make you any smaller, just makes everything less convenient.

 

[tomfcrist]

or a very deep wreck, with small tanks like I do.

Nothing about that sounds illogical

 

[Remy B.]

Back mount for me is no option as I can't reach the left valve because of my shoulder, and add some back problems, I thought about inverted doubles, but I went for what I see it works the best for me.

6 Tanks is not easy task, and I have not practice yet with 7 tanks that will be my max,

I have 2x AL-7L 200bar 80% bottles = 2800L, 1X AL40/ 5.6L 200bar 50% = 1100L, 2X 6.8L 330bar = 4200L and coming soon 2x 10L 230bar = 4600L, all of them have the same length, the 10L are just a little wider, but much less than a AL-80.

All my setup are small tanks compared to the tipical AL-80 or the 12L or bigger tanks, except I get almost the same capacity with a lot less weight and more redundancy, I choose 7L deco tanks because this setup get me the best combination in my own perspective.

AL-80 are very heavy when full and bulky tanks, and very buoyant empty, one AL-80 doesn't cut it for the 1/3 rule and two are just unpractical, with 7L tanks and in the unlikely event of deco gas loss from me or my buddy I have another complete bottle for that event, so no gas shering, no extra time cold in the water, and out of the water on schedule.

If you get to decide to penetrate a wreck at that depth, You can leave a combination of bottles at the entry point or go with all of them in, try to do that with AL-80 and Steel 12L or bigger, then you are without enough gas or you are very tight in the wreck.

But going back to the original question, why is it taught to place the Deco bottles in the front and the bottom gas on the sides ? why will this setup supposedly be better than the opposite of this?

 

[RainPilot]

I was taught lightest bottles on the bottom so they float up into the heavier ones. For me diving very low helium mixes it has so far worked out that my AL40 or 80 of deco gas is lighter than my back gas tanks.

I suspect that this is a hangover from guys diving steel back gas tanks and AL deco/stage bottles. I guess as long as your team all dive consistently there’s no issue with where you place your tanks.

I also find it easier to remove and replace the lower tanks as they aren’t bungeed on, maybe this has evolved from staging tanks prior to restrictions?

 

[leadduck]

When switching to deco tanks you should be able to see them and make sure you take the 50% and not the 100% tank at 21m. That's easier when they are below the sidemount tanks.