Two of Louisiana's largest shipbuilders, Bollinger Shipyards and Edison Chouest Offshore, have joined forces to compete for a piece of the U.S. Coast Guard's expected $22 billion program to enhance its cutter fleet, which will include more Arctic icebreakers. The two firms said Tuesday that they have formed a strategic alliance — called United Shipbuilding Alliance, or USA — to allow them to better compete with foreign shipbuilders who have expressed an interest in competing for the Coast Guard'