Cub floatplane Takeoff from Trailer

My parents setting up a Cub departure from a grass strip. Dad is driving the truck that tows the trailer; mom is the Pilot of the Cub. They’re both float rated, mom drew the ’short straw’ and got to have the fun. They accelerate to about 15 mph, she goes in on the power and dad hammered the accelerator on the truck. She departs, goes to ground effect for a moment then climbs out safely.