Keel, part 2

I have a t-shirt that has the old saying &ldquo;measure twice, cut once&rdquo; on it. That&rsquo;s decent advice, but I&rsquo;m finding myself measuring a lot more than twice before I get out the saw. To start with, in the cliffhanger to the last episode, I&rsquo;d determined where to cut the centerboard case, but hadn&rsquo;t yet worked up the nerve to actually cut it. Since then, I&rsquo;ve made…