Princess Cruises has announced that for the first time it will base a ship in San Francisco year round, beginning in May 2013.The extensively renovated Grand Princess will first offer a series of Alaska cruises during the summer months from the "City by the Bay," followed by a schedule of Hawaiian Islands, Mexico and the California Coast sailings during the fall 2013 to spring 2014 season. Last year the 2,600-passenger Grand Princess underwent the largest drydock in Princess Cruises history…