Slice red unpeeled potatoes in 1/4 inch slices. Stand slices in casserole dish. Put slice of onion between every 3 or 4 potato slices. Sprinkle with a little salt and add a little water. (1/4 cup water for 5 pounds potatoes). Lay bacon slices over potatoes. Cover loosely with foil. Bake at 350 degrees for 1 hour. Remove foil and bake until bacon is crisp.