Rinse beans. In a 4-1/2-quart Dutch oven or large pot, combine beans and 8 cups cold water. Bring to boiling; reduce heat. Simmer for 2 minutes. Remove from heat. Cover; let stand for 1 hour. (Or, skip boiling water and soak beans overnight in covered pan.) Drain and rinse beans.
In the Dutch oven or pot, combine the beans, ham, onion, catsup, salt, and 4 cups fresh water. Bring to boiling; reduce heat. Cover and simmer for 3 hours or until tender, adding more water, if necessary. Makes 8 servings.