We just pushed out of westy using a 40ft-lb electric troller and a deep cycle battery. It was way better than pushing out, and from Walmart the setup was only ~$250 for the battery and motor...(plus registration and lights, etc...) but Its not responsive enough to make me uuber happy with its performance.
That said, a commercial group of 5 16ft'rs in a mostly diamond config pushed in, unrigged, floated the weak rapids, rigged together, pushed to little D, unrigged through marble and then rigged again to push out in the flat water with a 8hp nissan and kicked our ass.
I'm having sexy dreams about someday affording this new propane outboard from lehr. Check this out:
I want one.