I have had mast base problems too. I sheared out the holes on the flange of the base. Seen on the right. Make sure that the holes you drill are not to close to the top of the flange.
After losing too many days of sailing with breaking/broken mast bases I formulated a hopefully permanent solution. I made the base on the left. The flange is twice as high as the original Hobie part and the flange is ½ “ thick. The increased thickness allowed for me to drill and tap the base. Now it is held in with button head cap screw instead of those pesky rivets.
