You have to be careful where you launch. Boat launches can be steep, crowded and slippery. I just go when the crowd is minimal and the ramp is nice. There a site at Havasu called site 6 that you would never dream of using. If you go across the lake there is a nice ramp that the is no problem. I also avoid steep and slippery ramps for obvious reasons. Lake Mead is probably a no-no but just down the river there is a nice ramp at Lake Mohave that is grooved and a slow decent.
I want to go up to lake Powell but I'm pretty nervous about that ramp.