Cannon Swivel Downrigger mounts. The corner just seemed the best place for function and strength, where it won't interfere with rod holders etc. I use Cannon 20T's with a CannonLink system tied to my Humminbird 1197si.
**side note!! after a few weeks, the Cannon plastic swivel mounts cracked at the bolt holes and in the middle of the plate. Gotta change them to stainless mounts now. Sometimes plastic is just not enough.
