OSG U.S.-flag spin-off prices common units.

OSG U.S.-flag spin-off prices common units.    A U.S.-flag spin-off of Overseas Shipholding Group expects to raise $142.5 million to $157.5 million through an initial public offering of common partnership units.
   OSG America LP, a limited partnership, said it expects to price 7.5 million units at $19-$21 per unit, which would net it $136.5 million at $20 per share. Underwriters also have the option to buy up to 1.1 million units to cover overallotments.
   Overseas Shipholding Group will retain about a 76 percent interest in the new U.S.-flag partnership.
   The new partnership will initially have a fleet of 18 tankers and tank barges for moving petroleum products, and may grow to 30 vessels by 2010 after new ships are added and older vessels are retired.