Scuper plugs
A plug used to close a scupper hole. Just like the scupper hole, a scupper plug is simple. They are a safety feature of sit-on-top kayaks, but their purpose is to plug up the scupper drain hole. A scupper is an opening, usually in a roof, bridge or roadway that prevents fluids such as rainwater from accumulating. Without a scupper, water or other fluids may pool, placing an excessive load on the walls of a structure or making roads impassable.