For my pontoon boat, I’ve removed the lights from the trailer and clipped them on to the boat itself, as Dave has done. They’re permanently mounted there, but as I get my ski boat going this year, I’m going to move it’s trailer lights to the boat and fasten them with velcro.
This has also saved me from bashing the lights on wonky ramp.
A happy side-effect is that I’ll be able to transfer the lights to other my other trailerables.