SM Stages - Top Mount vs Bottom Mount

[Manatee Diver]

For bottom gas stages while diving sidemount what are the pros and cons of top mounting vs bottom mounting your stages?

Mostly a cave diver, and we already bottom mount deco bottle(s).

 

[Celt]

They sit nice top mounted, but I would never top mount a deco bottle, I like to see them.

 

[kensuf]

You need to be able to verify the gas contents in stages before you switch to them. Bottom mounted allows for this very easily.

 

[rddvet]

I despise top mounted stages in sm. I've tried Edd's way and several other iterations. To me they all suck for several reasons. Like Ken said, it makes it very hard to identify your bottle markings visually. On top of that, I just don't have the shoulder mobility to make dealing with top mount easy, I've seen multiple people scootering with top mount stages dinging the cave ceiling, and I just find it uncomfortable.
Bottom mount is easy and fixes all of those issues. The only issue in bottom mounting is your profile gets bigger (but it does in top mounted too) and it takes some work to make sure your stage sits in tight. There are many methods that work well. Some are easy and some take gear alterations. A regular dir stage rigging works fine, but you do need to be careful with leash lengths or you'll get a loose, nmobile tank. I personally use what I call the "Dave stage" in honor of my friend who passed away and was the inventor. The pros are your tank is tucked hard against your body and doesn't move. The negative is it requires the first stage to be facing down. Some people have huge problems with that. Personally after diving that way for 7+ years its a nonissue. In big cave or scootering it's not exposed at all with good technique. I've gone through some pretty small stuff with a dave stage and you just need to keep your technique clean so you don't hit the first stage, but that's not hard to do because the stage is so tight against you.

 

[JonG1]

Do you have any images please rddvet, I am just about to add a stage to my SM rig (OC and CCR) but planning to use the Steve Martin style bungee set up (on the top and bottom bolt snap) but be interested to see your set up.

 

[Manatee Diver]

Ok here is another question if all your stages are bottom mount, are you limited to just two bottles? Or how do you fit a third? Like two AL80s and a AL40 O2 bottle?

 

[J-Vo]

Ok here is another question if all your stages are bottom mount, are you limited to just two bottles? Or how do you fit a third? Like two AL80s and a AL40 O2 bottle?

Bottom mounting 4 80s is doable. I did it for trimix class and regularly do 3 in my diving. I've been thinking about a 3rd deco gas for some bigger dives, so that will be 4 80s as well.

 

[rddvet]

Do you have any images please rddvet, I am just about to add a stage to my SM rig (OC and CCR) but planning to use the Steve Martin style bungee set up (on the top and bottom bolt snap) but be interested to see your set up.

I’ll take a few when I get a chance today or tomorrow

Ok here is another question if all your stages are bottom mount, are you limited to just two bottles? Or how do you fit a third? Like two AL80s and a AL40 O2 bottle?

2 stages and a deco bottle is all I’ll do in sm. You can do 4 bottles, but it’s easier to rotate one to your hip during, a leash, or your butt.
Personally if I need 4 bottles, I’m diving bm or a rebreather. 4 bottles in sm is doable but a pain in the rear

 

[kensuf]

Ok here is another question if all your stages are bottom mount, are you limited to just two bottles? Or how do you fit a third? Like two AL80s and a AL40 O2 bottle?

Ass clip the third bottle via a stage leash. Pull it out and use it when you're ready to go to it. You can even do this with four, five, or six stages.

 

[tbone1004]

Ok here is another question if all your stages are bottom mount, are you limited to just two bottles? Or how do you fit a third? Like two AL80s and a AL40 O2 bottle?

what @rddvet and @kensuf I WANT to be able to top mount because the profile is better and I had things hanging below me, but it just doesn't work. I've tried everything, helped optimize some of more prominent methods of top mounting, but I just don't like it, so I bottom mount.

In cave diving, you get to cheat which is nice. My deco bottle/s just get nose clipped to a butt rail/hip d-ring, etc. and dropped off. They don't have to look good on the way in because you aren't carrying them very far. IF we take a third stage which is a safety bottle when scootering, it is butt-mounted and trails behind. It goes away in the slipstream of the diver when on a DPV, and you can grab it with your thighs to keep it well mannered. It's annoying with nitrox when full, but it's tolerable.

We dive LP121's to get rid of the quantity of stages, and anything more than 2 stages for penetration is done on a CCR. If you have to carry more, dive doubles or a rebreather where you have a lot more real estate available. If you need to do the dive on sidemount for whatever reason, do a setup dive and drop the deco bottles and at least the first stage then you can use a leash when picking them up on your way out.

Sidemount really is not the answer when you need more than 4 bottles though, and you should seriously consider alternate configurations. I also believe that CCR's are far safer when you are getting that far back in a cave because they buy you time to solve problems that OC simply can't do.

If you're doing double stage dives, I'd recommend leaving a 4-8lb clip weight in the deco room with your O2 bottles so you can clip all of the dead stages off when you get back. Deco on those dives is long but not distinguished, so having the clip weight to get rid of all of the bottles is really nice. Use the leash and then when you're ready to come up, you just grab the weight and bring it up with you.