I am a bit of a lone wolf here in my area when it comes to model boating, so I have to video my operations myself when at the local park pond.
In the past I was able to rubber band my cell phone to the top of my radio, and hope it didn't fall off into the drink!

While at the "Dollar Tree" store one day I found some folding cell phone stands. This got me to thinking, if I could attach parts of this to the top of my radio, velcro could be used to attach and secure the phone, making my hands free to control the boat.

I removed the bottom portion of the stand simply by removing the plugs which made up the hinge of the device. I first tried to secure with super glue, but both being an engineering type plastic, it would not stick. I then got out the E6000 glue which is a more flexible type adhesive but requires a lot longer set time hence the magnets holding the two together. When that set, i was able to then glue the front portion ahead of the antenna of the radio.
Adding velcro strips to both the stand and the phone yielded a very secure but removable attachment. The radio is able to be moved in a 360 circle without the phone falling off! I also have recently got a new cell phone, so the old one makes a perfect candidate for a dedicated video camera. If it falls off no harm.

Hope this may help others in the same boat!😊