Bracket Mounting Disks - Quantity 6An aluminum backing support for a trolling motor mount is a 2-in. diameter disk made of 1/2 in. thick 6061-grade aluminum. The backing support is designed to provide additional reinforcement to the mounting area of the boat where the trolling motor is attached. Benefits of using mounting disks:Load Distribution: Multiple backing supports can distribute the load over a wider area compared to a single backing plateFlexibility: Using multiple backing supports allows for more flexibility in positioning and alignmentAccessibility:  Using multiple backing supports can make it easier to maneuver and install the components in tight spaces, as you can insert them one by one and secure them individually*When using these backing disks, it is important to always have a fender washer between the disk and the lock nut. These disks are designed to work with 1/4-20 Phil flat machine screws. Sea Brackets recommends using machine screws with coarse threads.