I got some of the RAM rod holders last year and they work great.

Here are the parts to use if you already have Fish-On bases.

RAM-117B - RAM-ROD FISHING ROD HOLDER

RAM-201 - RAM DOUBLE BALL SOCKET ARM ASSEMBLY

RAM-1056B - RAM POST FISH-ON,ATWOD,SCOTY,GEARLOCK

You can get all the pieces from Outdoor Emporium in Seattle. However, its cheaper to buy the rod holder form Cabela's ~30.00 ea and then buy the conversion posts from Outdoor Emporium ~15.00.

They are kind of expensive but I think worth it. I even got a longer arm for my middle rod.

Here is a pic form chum season that shows the rod holder in the lower left.