Oops! I drilled a hole in my hull!
In the short run, stick an 1/8" diameter bolt through the hole (head out) with a large fender washer and a rubber gasket washer under the fender washer under both the head and nut. Use a Nylock nut in the inside of the boat so it won''t back off. You shouldn''t have much of a problem if you maintain your zincs and haul out in the next year or two unless you have a cored hull. If you have a cored hull you risk getting water into the core of the boat.