I mounted 2 rodholders with Rule Elastomeric Sealant and 4 14X1 1/4" stainless screws. They seem to be very stable and do not budge. I took the boat out Saturday and caught 6 catfish, the largest weighing 8.5 lbs in strong current. The rodholders held up fine. I'm convinced the 4 screws and sealant were all I needed!
Thanks!