U.S.-flagged container ship âNational Gloryâ kicks off the new service when she departs Houston for San Juan May 29, 2013. The new 14-day service, which is being provided by National Shippers of America (NSA), is called "Isla Verde Express" and will provide customers with more transit options and supply chain flexibility in this "under-served" market, NSA officials say. Mississippi River have few options to move cargo to and from Puerto Rico without having to use an East Coast port," said Torey Presti, NSA president.