this has happened to me twice. 1st time girlfriend driving and she crossed the rope picking me up. it was in 60 feet of water. dropped the anchor and grabbed the leather man and did some diving for about 40 minutes and finally got it cut off the prop and shaft.

2nd time, pulling my son in about 35-40 feet of water and everthing is going fine then all of a sudden there is this god alful sound (thought it was the transmission). turns out we picked up about 30 feet of submerged rope. again anchor, leather man and a lot of diving.

so far knock on wood have not had this happend again in over two year.
karma.