The upper part is going to be tricky. Not much room to get at it. This portion is again only 1 layer of 3/4” core. [if that)
i think I can get my multi tool in there to cut it out. Grinder will fit as well I hope. Glassing it back in will be tricky but I’m not removing the cap on this big girl for this small area. The wood actually appears solid here as it’s above water line and no holes in the area.