COSCO (Guangdong) Shipyard has completed the first of at least two conversions turning supramax bulk carriers into containerships, according to Alphaliner. The 53,000 dwt Pu Tuo Hai, a 2007-built Diamond 53 bulker, entered the Guangzhou yard on June 10 and emerged a little over three months later as the 2,528 teu Singapore River. The ship …