Mine is mounted on a piece of 7/8 stanchion pipe about 3 feet long. I sits in a swivel socket and clamps to the transom with a U Bolt. It uses a Top-cap and deck hinge low on the transom and the top slide clamps to the u bolt. I took the set screw out of the cap so the pipe just sits in it and use a 1/4 inch bolt for the pin in the slide. Both lights are mounted on the pole and as long as everyone is sitting down can be seen over their heads. Installation and removal is easy requiring a small crescent wrench for the bolt in the top slide. The U Bolt is of the lifting rings for hoisting the dinghy.

http://www.suncorstainless.com/top-slide

http://www.suncorstainless.com/top-cap

http://www.suncorstainless.com/deck-hinges-90-degree-concave