RedactedNarrative: Operator had just anchored in the fast current of the river and attached the anchor rope to the starboard side at the stern, when another boat traveling at a slow speed passed the anchored boat.  The small wake came over the transom and the operator attempted to cut the anchor line with a knife when he lost balance and fell over the starboard side of the boat.  The operator stayed afloat because of his rain gear and held on to fishing poles hanging over the side of the boat and a type III PFD as he and the boat drifted down stream for about 1.25 miles.  The operator estimated he floated down stream for approximately 45 minutes before a witnesses observed him floating past her residence and asked if he needed assistance.  Another witness rescued the operator with a pontoon boat and took him to shore and later recovered the boat, which was half filled with water, but still upright.