There is an easier and I think better way. Remove valve by cutting 3 small cut in a triangle fashion at hole(these are probably only about 1/4". remove inner broken part of valve and replace. Install round patch over hole(about 2" in diameter bigger than hole. Recut/drill hole with a tight fit for the male half. This patch will serve to strengthen an area that is susceptable to developing leaks anyway and the valve being tightened will help if you haven't done a good job bonding. Don't make that big slice in your boat! That slice if you've gotta do it that way(but don't) only needs to be a1/4 an inch greater in diameter than the outside part(male) of the valve.
There is an easier and I think better way. Remove valve by cutting 3 small cut in a triangle fashion at hole(these are probably only about 1/4". remove inner broken part of valve and replace. Install round patch over hole(about 2" in diameter bigger than hole. Recut/drill hole with a tight fit for the male half. This patch will serve to strengthen an area that is susceptable to developing leaks anyway and the valve being tightened will help if you haven't done a good job bonding. Don't make that big slice in your boat! That slice if you've gotta do it that way(but don't) only needs to be a1/4 an inch greater in diameter than the outside part(male) of the valve.
PS final tightening of valve(last quarter turn) done with chamber fully inflated.