While it may seem like the attachment of a slung pony is 'much like' side mounted tanks, pony bottles attached with stage rigging can definitely 'dangle' quite a bit below the plane of the diver's body. Diving a sidemount configuration does two things: 1) the bungee pulls the neck of the tank in close to the body, 2) while clipping to a butt plate brings the bottom of the tank in close to the body.I'm pondering making a SM rig out of my Transpac, and was wondering about the reason for the butt plate. I usually sling a pony, and clipping it to my chest D ring and waist D ring keeps it in a position much like side side mounted tanks.
Yes, even after you bring the tank neck in close to your body with the bungee, the bottom can still dangle / protrude. (OK, if you are simply diving an open water sidemount configuration - not moving around in close / tight spaces, that may not be a big issue, although you are not particularly streamlined.) Clipping the bottom point of attachment of the tank to a buttplate adds the second element of 'snugness'.Does the butt plate just pull the tank a little tighter to your body or what?
While a number of people do this, it is not necessary if the tanks are properly weighted / configured.saxplayer1004:with the 80's they have to get moved forward to the hip d-rings when they start getting floaty
Very good point. More than a few divers using a sidemount configuration with a TransPac/Nomad - even in a wetsuit - may require some added weight with two AL80s. One approach is to shift some of that weight from the waist to the bottoms of the tanks. I prefer to use cambands (instead of stage rigging) on the bottom of the tanks, and I slide Halcyon (or XS Scuba) weight pockets onto the cam bands, and position some weight in the pockets (usually 2-3 pounds in each).Dive-aholic:Adding weight to AL80s makes it so this isn't an issue.