One half of a cargo ship that ran aground on a New Zealand reef three months ago began sinking into the ocean Jan. 10. The stranded cargo ship Rena broke in two pieces on Jan. 8 after storms with 19-foot waves pounded the vessel. The Greek-owned Rena ran aground 14 miles from Tauranga Harbor on North Island on Oct. 5, 2011, spewing heavy fuel oil into the seas in what has been described as New Zealand's worst maritime environmental disaster.