@southsoundtree , yes, Aaron has it right I believe. When I visited Paul, we really had a great time coming up with names for things. He had a way of actually leaning inward with one hand way forward on longer limbwalk returns. Lean. Lean on me. Who wrote that somg? Bill Withers. Then limbwalking was called Bill Withers.
The Helicopter Belay was similar. Gordon was offering RE Nano swivels built into the Bulldog Bone as an attachment point. I was running a swivel on my bridge, which then went to a delta screw link which housed the two Bones w/ Nanos. The Bone would account as a belay device.
When running twin, parallel stationary ropes, the Bones sat side by side, close enough to operate with one hand. Once on rope was redirected, the swivels would allow each Bone to orient freely as needed. If one rope was under load and the other was fully slack, the slack Bone could be removed from its line and spin any which way…like a helicopter. A helicopter belay if you will.
Kind of a cool name for it so it stuck, and man was it clean and effective. I miss climbing that way. Such a clean way of getting around as if on just one rope until you want two and the system magically accommodates. Position anywhere in space.
The Helicopter Belay is great for Ghosting through redirects! Like a ghost through a wall, one rope passes a redirect while you are fully supported by the other, then you hang in the redirected line while passing the second rope through the same redirect. Ghosting. =D