Good news / Bad news. As I was leaving for work this morning I double checked the clearance for those 181/2" 3 rod boxes. They would fit but won't clear the rod holder. They have 2 rod boxes that are 15 7/8" x 54"l. They will fit. I'm wondering if I could somehow modify these bigger boxes to fit around the rodholder? Anywhooo, check out...
http://www.fpmarine.com/Plastics.htm
They seem to have lots of neat stuff.
Airslot