The first arc welds on the keel of Washington’s new 144-car ferry will be made later this month by the leaders of the state Legislature transportation committees, Sen. Mary Margaret Haugen of Camano Island and Rep. Judy Clibborn of Mercer Island. The two legislators will join Washington State Ferries officials and ship workers at 11:30 a.m. Thursday, March 29, to commemorate the moment when the vessel’s keel is laid in place at Vigor Industrial’s Harbor Island shipyard in Seattle. Keel laying, the maritime equivalent of placing a cornerstone, is a traditional milestone in ship building.