List of materials: 2" pvc pipe 2" pvc tees 2" pvc 90's 2" pvc 45's plumbers glue & primer(or screws if you don't want them glued) First you cut the pvc pipe to however long you want the holders spaced apart. Then glue the 90's on the ends & tees in the middle (example-90-pipe-tee-pipe-tee-pipe-90) until you get them how long you want. Then drill holes in the bottom for drainage since they might get water in them. Next you glue however long a section of pipe you want on top of the tee for however high you want them, then glue the 45's on. Last you can use radiator hose clamps to hold them to the rail or maybe even muffler clamps. You can tilt them up or down to suit your needs & no drilling in the boat!!!