Well...on the portside the pin is about 3/8th dia and threaded. On the stbd side it is a half inch ss pin with no head for a tool. no room for vice grip or the like. So it looks like its a ss 1/2 inch round with one end turned down and threaded.Would post pics but now cant find my phone. What if I just drilled it out with a 1" hole saw and used a ss 1" solid round? Id like to go bigger. This is my first centerboard boat.