The Niagara Queen II is a small icebreaker that Ontario Power Generation uses to keep the inlet ports open at their plant on the Niagara River at Niagara Falls. Niagara Queen II is a shallow draft river vessel designed by OPG and STX Marine. She replaced the Niagara Queen, a modified tugboat icebreaker operated by Ontario Hydro and now with OPG. See also William H. Latham (icebreaker) - a similar (but larger) vessel used by the New York Power Authority. References Icebreakers of Canada 1992 ships