From the manual:
I just got my O'Day 22 manual from Daniel, so at least I can quote from it. I have not done this myself (haven't even sailed the thing yet!), but here's what Bangor Punta said, way back when: "The O'Day 22 has 600 lbs. of lead ballast [more on later boats, I think-Rich] glassed into the keel, which is more than adequate; however, you can add more, if you prefer more stability. The easiest way to add is to pour lead shot (available at any good sporting goods store into the keel area through the bilge drain plug. You may even mix with catalyzed resin for a more permanent job, but be sure area is dry. We have customers who have added 200 lbs in this manner, but be sure to increase positive flotation at the same time in order to support extra weight, should the hull take on water through a leak or hull puncture." They make it sound pretty easy! Rich.