Help wanting to mount a BTU Shocker into a swivel head

Hi There, New to this column. I have just purchased a BTU Shocker and I need help with mounting it. I have a rod holder at the front of my small alluminium boat. I intend to mount a tube into the rod holder and I need to make/adapt some sort swivel head to make the BTU into a searchlight. I dont need anything fancy and it doesnt need to be that strong. SO anyone with any ideas that I can mount the flashlight to and come up with some swivel arrangement???
I will remove it from the rod holder when not utilising it!
Any help much appreciated.
Bruce