Leak at stern hawse fairlead - found big hole in port side

The boat is still leaking at the starboard bollard so I change the butyltape to some sikaflex 291i so it can be complete watertight by the two screws. After the little operation in starboard side I start to pull off the port bollard and gets stunned over a giant hole I find in the side of the boat, clearly here where the water has bled into the cabin. I fill the hole with some epoxy and cover the area with a layer of sikaflex 291i. In starboard side I will like to drill some holes but my Dewalt drilling machine is to long so I can't drill a straight hole. The solution to that is to buy a cheap shorter Biltema CD108B drilling machine so it can fit below the railing.