The trawler was first spotted floating near British Columbia by a Canadian military air patrol , and it was then determined that it had been adrift since the tsunami , Canadian officials said last month . NEW : the Ryou-Un Maru official says Canadian trawler has capsized . NEW : It sank about 180 miles west of North America , an official says . Authorities say it is a navigation hazard . The boat is part of a giant debris field making its way toward Southeast Alaska .
NEW : the Ryou-Un Maru official says Canadian trawler has capsized . NEW : It sank about 180 miles west of North America , an official says . Authorities say it is a navigation hazard . The boat is part of a giant debris field making its way toward Southeast Alaska .