Swamp backstroke update

Yesterday I finally found the increment of speed I've been looking for half the summer. The speed key in the high-gear of the swamp backstroke is to bring the inward sweep of your hand very close to your hip. I can think of several reasons why this works, but it does work amazingly. I could feel myself making a bow wave (for the first time ever,) and every so slightly going prow-up like a motorboat.

Pick any or several of these reasons:

the well-known clap-fling effect may help reverse the circulation of the flow around your hand for the return outward sweep,

because flow velocity next to your body can only be straight downstream, forcing the slipstream of your hand against your side converts some of the useless side-to-side momentum of the slipstream to downstream momentum,

by applying your thrust near the widest part of your body, you energize the boundary layer in a way that reduces drag,

keeping the thrust-producing maneuver as inboard as possible reduces drag from the shoulders and arms in making the stroke.

Also, the muscular effort in this position seems easier.

I can only say that the swamp backstroke is already fun and getting faster.

The dream would be to somehow combine this hip-clapping underwater stroke with the underwater dolphin kick to make an underwater backstroke, surfacing only intermittently to spout like a dolphin. I'm not nearly athletic enough to try that.