We built this setup and had it all inspected and approved for a several kilometer trip too and from the ramp in daylight hours.
It has waterproofed semi trailer maxi brakes and hydraulic ram's fitted to the front to lift and tilt the trailer for launching and retrieve.
It requires flashing lights, wide load signs and a pilot vehicle.
It's now over ten years old and works as good as the day it was made, the boat is 10 meters long and as for overall wieght, lets just say its heavy ...foxy