I have a 1989 wellcraft Nova 23 xl. On the top foot ledge where you would board the boat just rearward of the side glass there is some unidentified item that has puzzeled me since we got her. It is round, about 2 1/2 inches in diameter. It is approximately 1/8 inch thick at its edges & tapers to about 3/8 inch thick toward the middle. It has 4 screws attaching it to the boat, and a 1/4-20 treaded hole in the middle. There is one on both the port & starboard sides. They are not used for the cover or camper top. Any ideas? 
