I made this Gopro mount for the fishing pole sockets based on parts suggested by Yakass.
It's 1 1/4" pvc pipe with a 1 1/4" union glued on one end and a 1 1/4" to 1/2" NPT adapter glued into the other side of the union.
The other end of the pipe has a 2 1/2" wide strip of 1/16" EVA foam glued on with contact cement 2 5/8" from the bottom of the pipe.
The NPT adapter on the camera end has a 1/2" brass close nipple screwed into it and a 1 1/2" ram ball to 1/2" NPT female is screwed onto that.
A 1/4" x 3" eye bolt goes through the pipe to provide a leash point at around gunwale level.
The Ram parts are:
RAP-B-202U-GOP1 Ram Gopro mounting base 1" ball
RAP-BC-201U Ram socket arm W/ 1" and 1.5" sockets
RAM-218-1U Ram single ball w/ 1/2" npt hole
Not shown is RAP-401U Ram Tough Claw W/1.5" dia ball to allow mounting the camera to other places.
Chris