After 3 1/2 years of uncertainty for North River Boats, a new owner has erased that doubt. A Portland-based limited liability company, NW Bend Boats, formed for the purpose of buying the assets of North River Boats, completed the acquisition Aug. 15. NW Bend declined to disclose the terms of the sale. The new owner will keep the North River brand, but will have no legal ties with the company once owned by Brian Brush, who’s serving time in a Washington state prison for murder. Even before Brush killed his estranged girlfriend, his old company had been in receivership since …