The other day I was trolling a countdown Rapala for suspended crappie and began acquiring severe line twist.  What would cause this?  I've never seen a crankbait cause fierce line twist before.  I wonder, maybe, if sometimes I wasn't trolling too fast at times and the lure was rolling.  Have I answered my own question? 

Yes, you answered your own question.

Try trolling slower, and if that doesn't work, use a swivel