: To guarantee that the drill won't wander on the hull while
: starting, drill the right sized hole in an appropriately tapered
: piece of scrap, and then clamp/strap/tape the scrap securely to
: your hull.

: Use the scrap as a zero clearance guide and drill through the hole
: enough to start the hole in your boat. Take the scrap off, and
: then drill the rest of the way. You could leave the scrap on,
: but it might prove easier to get it square with the boat without
: it on there.

I'd use that method to drill the pilot hole then use a hole saw.