A U.S. Coast Guard cutter poured cannon fire into a Japanese ghost ship that had been drifting since last year’s tsunami, sinking the vessel in the Gulf of Alaska and eliminating the hazard it posed to shipping and the coastline. The cutter’s guns tore holes in the 164-foot Ryou-Un Maru on Thursday, ending the abandoned vessel’s long, lonely journey across the Pacific. As the crew pummeled the ship, it burst into flames and began taking on water, officials said.