Cup holder

I'm thinking about making a cup holder for the yak. Anyone have any ideas? I was thinking about bolting down a cap for pvc then cutting a pvc tube to fit a can so i can slide it in place and remove it when im not using it so it's just the cap for the base? I have a cobra tandem that i basically made into a fish and dive and I installed hobie circle hatches. I don't have alot of flat space, so would putting it on the hatch mess the hatch up?