Crock Pot Boston Baked Beans

2 cups navy beans
Cold water, as directed
1 cup tomato sauce
1/4 (one-quarter) cup molasses
1 tablespoon mustard
1 tablespoon chopped onion

Sort, clean and wash beans. Place in a large saucepan and cover with eight cups cold water. Cover and soak beans overnight. Drain and discard water. To soaked beans add six cups fresh water and bring to boil for ten minutes. Drain and place prepared beans in the crock pot. Add six cups fresh water and remaining ingredients. Cook all day in crock pot on Low. Serves six.