back in late 70's maybe early 80's I was fishing on lake norman in a little boat with only paddle power- we was paddling from 1 cove to another with bout 5-6 crappies on a stinger behind the boat(old school stringer no snap hooks) when something slammed it so hard it rocked the boat- all the crappies was stripped off the stinger 'cept for a couple of heads- to this day I still wonder what that was!