Don't think there is a minimum length. However, the wind can really get those lakes rolling. Just check what direction the wind will be coming out of the day you are there. When it is out from the north or south, be careful........

Just be careful, one time I was fishing a small bass club. Ran across Barkley and up the lake about two miles. I had 24lbs of bass on four fish and couldn't weigh them in because the lake was so rough. Had a 15.5 foot bass boat.