One of Singapore's leading shipyards, Singapore Technologies Marine (ST Marine), has been awarded a third contract from a unit of Crowley Maritime Corporation to build four additional tug barges, according to a report in The Bulletin International of Panama.The US$240.7 million contract will bring the total number of barges Crowley Maritime has ordered from ST Marine to 10 with a combined value of more than $536-million. The report said delivery of the latest four barges is expected between 2009 and 2010.