This lightweight plastic fixture will hold our Typhon series lights on your transom without any modifications. It has 3M VHB tape on the back (same tape that holds your car side molding on) to secure it to your transom. This allows a place for the light to stay so that it doesn't "dangle" going down the road.
It has a drain hole in the base so any water that gets in, will go out.
There is basically zero water pressure on your transom so the fixture will not be going anywhere if installed per the video link below.