Repaired a mast step; by removing the bottom, there was only green gelcoat left in the circle of the mast step. The square wooden piece was on solid ground. When the mast had been grinding all the way down, it would go through the bottom. I guess this is the boats history. Old repairs showed some kind of cement in the bottom of the hole. Now it's solid, I threw in a piece of 3mm aluminum plate for extra protection.
Banbury 1974 ? boat.