making a waterer out of a cooler

[goochgirl]

Someone posted that they had made a waterer out of a cooler since the insulation kept the water warm. Its not even December, and I'm sick of finding ice in the girls water every morning. Well, that, and it means I have to go out earlier and in the cold

If anyone has pictures and/or instructions they would be appreciated. I don't have electric, so a warmer won't work for us.