Federal officials are working to finish a proposed rule that threatens to dramatically alter the itineraries of many foreign-flagged cruise ships, such as those operated by Carnival Cruise Lines, Royal Caribbean and others, by requiring much longer port stays.The proposed change would require 48-hour stays, instead of the usual four- to 12-hour visits, at foreign ports of call, possibly reducing the number of stops during trips of a week or less.It is aimed at helping the U.S.-flagged ships operated by Norwegian Cruise Lines America on Hawaiian cruises compete with foreign-flagged cruise lines sailing from California. Almost all cruise ships operating from U.S. ports are registered in foreign nations to avoid the cost of meeting U.S. labor, health, safety and environmental standards.But the impact could have much broader implications, imperiling cruises from U.S. ports to Alaska, Canada, New England and some to the Caribbean, according to critics.Cruise vacationers may find companies offering more limited itineraries and fewer three and four day trips.Source: usatoday.com; read full article here.