Place beans in a Dutch oven; add water to cover by 2 in. Bring to a boil; boil for 2 minutes. Remove from the heat; cover and let stand for 1 to 4 hours or until beans are softened. Drain and rinse beans, discarding liquid.

In the same pan, saute onions in oil for 2 minutes. Add celery; cook until tender. Stir in the beans, water, ham, potatoes, carrot, Worcestershire sauce, salt, thyme, pepper and bay leaves. Add ham bone. Bring to a boil. Reduce heat; cover and simmer for 1-1/4 to 1-1/2 hours or until beans are tender.

Discard bay leaves. Remove ham bone; and set aside until cool enough to handle. Remove ham from bone and cut into cubes. Discard bone. Return ham to soup; heat through. Garnish soup with parsley. Yield: 15 servings (3-3/4 quarts).