Ham Hocks and Navy Bean Soup

1/2 pound dried navy beans
1 quart water
1 ham hock
1 medium onion, thinly sliced and diced
salt and pepper to taste

Sort and wash beans. In a large saucepan, combine beans, water and ham hock. Bring quickly to a boil over high heat. Remove foamy scum with a clean damp cloth wrapped around a fork. Reduce heat so soup barely simmers. Simmer until beans are tender, 2 to 3 hours. Add onion during last 30 minutes of cooking time.