Place water and salt in a dutch oven and bring to a boil. Slowly add cornmeal and boil for 5 minutes, stirring constantly. Add shortening and molasses and let cool. Dissolve yeast in ¼ cup luke warm water. Add yeast and 2 cups of flour to the dutch oven. Add enough additional flour to make a sticky dough. Knead well on a floured surface. Let rise until doubled. Split into 2 loaves and let rise again until doubled and light. Place loaf pans in the bottom of a dutch oven, cover and bake at 400 degrees for 45 minutes