how to launch a big boat without a trailer at gravely point DC boat ramp?

I went to test my PWM for my big motorguide trolling motor 70 lbs 24 volts at the Gravelly point boat ramp in DC off the runway of Reagan National Airport. I was able to leave and this big boat on a big truck arrived. I stayed for another half an hour to see people unload it. very cool -

watch the video here - https://www.youtube.com/watch?v=fjBY05t5vNs