Man, I dont know if I'd even fish for Gators in somethin' like that...
But, with a boat, I'd move every 45 minutes until you get into fish. I'd try some of the deep, slow moving holes on the Willamette, look for the bedrock(?) shelves you can see on the bank, and assume the underwater terrain is about the same. Fish there. Somewhere between Hogg Island and Elk Rock Island.