Butt rails, drop d's or waist d's

[grantctobin]

I've seen a lot if SM divers clip the primaries to waist d rings and stage/deco to drops at rear.

Is there a reason why you do it the opposite way Grant.

I feel that it depends on the quantity and buoyancy characteristics bottles being used. If I was using 3 AL80 on OC, I'd likely crossclip. In a cave environment on OC, it's rare that I'd be carrying deco bottles very far and any stages being carried will grow light enough during use that they hug into the body or will be tail light and out of the way nose clipped or on a leash. If I was using 2x painted Faber LP85@3600psi (13L ~182bar filled to 250bar) and two stages carried to half+200 with the additional reserve added to the LP85s, the LP85s should at no point grow light enough that they needed to be reclipped because of tail lightness. TBH if I needed 2 stages with a set of 85s, I'd either bring a CCR or move to 17 or 19L and bring only a single stage, all of which are likely heavier.

I'd add that use of dryglove rings can contribute to preferred practice. If you're using standard rigging, reaching under your primary tank to grab the boltsnap of the stage and then clipping it to a drop d-ring can be rather difficult. Caveat I haven't spent much time with the Mexico/ProTec style bungee rigging, which would aid that process because of the adjustability of the lower strap.

I don't have a ton of time with >1 slung cylinder on harnesses that have built in butt rails (SMS75, older Nomads). In those instances. I'd clip the primary steel cylinders to the butt rail and elblow them out of the way to clip AL40s or 80s to a hip d-ring.

 

[Bierstadt]

I do drop d's for my primaries and waist d's for deco bottles.

 

[J-Vo]

For 12s (LP85s) drop D's are too far back for me. I use sliding waist D's for all my primary's and fixed length bungee leashes to the drop D's for everything else. I'm currently finally figuring out the fixed bungees for deco/stages bottles. Previously I was using MX stile adjustable bungees, but it's just too fiddly.

I have never seen the need for but rails. Even Worthington Steels with 4k PSI have been just fine on the drop D's.

 

[rjack321]

I don't have a ton of time with >1 slung cylinder on harnesses that have built in butt rails (SMS75, older Nomads).

Don't bother, its sucks more than sucky suck.
2x 85s of 21/35 and 2x al80 of 25/25 is a complete and utter CF on a SMS100

 

[Marie13]

The regular D ring didn’t work for deco bottle for me for deco bottle. Hard to clip to (for mashed against my body). The drop D ring left the bottle hanging too low. I think I’ve got a rigid/fixed D ring in my spares box from backmount days I’m doing to try this weekend.

 

[J-Vo]

I'm using 10mm loop bungies. Easier to handle with dry gloves, more stretch, and put more torque on the tank. I believe it keeps me from having to move the tanks across as much "range" around my waist, so don't need to go as far back with heavy tanks or as far forward with light tanks. Really helpful with 108s of 14/65. Those things go from super heavy to more floaty than AL80s in the course of a dive.

 

[CPRC]

May I jump in here? I am curious as to why the general consensus is to use the waist Ds for aluminums and the rear drops for steels. Is there a basic reason for this? I’ve only got about 20 SM dives in now. I have a Katana bc. I use 2 waist Ds on each side and they seem to work fine. But my bc has these square hangers (just couple inches lower than waist harness. I haven’t used them yet except to clip my butt pocket and such. I’m just wondering if I am not realizing their real purpose?

 

[Mike1967]

@CPRC
I have the XDeep but I do the same as you, I'm using steels though. You need to use waist Ds for alloys so you can slide them or move to a more forward set when the tank butts get floaty.

 

[rjack321]

May I jump in here? I am curious as to why the general consensus is to use the waist Ds for aluminums and the rear drops for steels. Is there a basic reason for this? I’ve only got about 20 SM dives in now. I have a Katana bc. I use 2 waist Ds on each side and they seem to work fine. But my bc has these square hangers (just couple inches lower than waist harness. I haven’t used them yet except to clip my butt pocket and such. I’m just wondering if I am not realizing their real purpose?

A full steel 108 of nitrox hangs like a brick. You need the rear hangers to keep it parallel and along your actual side

A near empty al80 (or any tank with hypoxic trimix) wants to stand on the valve - upside down with the tail in the air. You need the waist rings to keep the tail down and the tank parallel to your body and along your actual side.

 

[CPRC]

Thank you. That was what I was guessing.