Norwegian Cruise Line is to spend $400 million revamping nine of its 14 ships.

The ‘Norwegian Edge’ project is running over two years to upgrade older vessels to reflect the “premium look and feel” of the line’s newest ships.

The refurbishment started in October 2015 with a renovation of Norwegian Epic, followed by Norwegian Gem in November.

Seven additional ships will go into dry dock for enhancements, starting with Pride of America and Norwegian Sun (pictured) this spring; Norwegian Dawn in the summer; Norwegian Spirit, Norwegian Sky and Norwegian Pearl in winter 2016-17 and Norwegian Jade in spring 2017.

“As the cruise line with the youngest fleet in North America, this extensive enhancement programme will offer much more than the traditional soft goods décor updates and serve to make the line’s ships into essentially new vessels,” the company said.

President and chief operating officer, Andy Stuart, said: “Norwegian has a long history of investing in its fleet to offer guests the latest and greatest innovations, but the investment to raise our ships to The Norwegian Edge standard of excellence takes it to new levels.

“The new standards of The Norwegian Edge programme will entice our guests to return again and again to ships that will look and feel as if they were just delivered, with all new menus and new dining experiences, visiting incredible exclusive destinations that reflect the quality finishes, amenities and outstanding service found across the Norwegian fleet.”