I need to put new keel bolts in the keel of my Catalina 27. I have received some info from catalina on what to do. Essentially I need to drill holes from the top down through the bilge, and then for each hole, drill a larger diameter crossing hole from outside the keel, so they intersect. Then I would place a threaded SS bolt from above, and screw it into a threaded piece of SS placed below. They recommend 1/2 inch diameter threaded SS rod from above, and below a 1 1/4" diameter 3 " long SS rod with a threaded hole to accept the rod from above. I am not sure at this point whether the keel is lead or iron. I am trying to find that out. What would I need to drill these holes, and how hard would it be? I was told elsewhere a magnetic base drill would be necessary. I would appreciate any information.