Which cruise lines are making headlines this week? Travel journalist Donna Tunney — ShermansTravel’s cruise expert — has all the latest news. Check back every Tuesday for trends, new amenities, and money-saving ideas that help you plan a perfect vacation at sea. 

Thought the Oasis of the Seas -- the world's biggest cruise ship since 2009 -- is humongous at a 5,400-passenger capacity? In spring 2016, Royal Caribbean International is launching an even bigger Harmony of the Seas, slated to accommodate 5,479 guests. Harmony's design closely follow the Oasis with the concept of themed “neighborhoods,” such as Central Park, Boardwalk, the Royal Promenade, and Youth Zone. But new additions include three multi-story water rides, along with some high-tech features that debuted on the line's Quantum of the Seas in late 2014 -- including the robot-powered Bionic Bar, wristbands that double as stateroom keys, and onboard credit cards. 

Here's a suite deal. Through April 6, Norwegian Cruise Line is offering guests who book a suite or accommodations in ship-within-a-ship The Haven a bunch of perks that add up to big savings. These lucky cruisers will receive a free Ultimate Dining package (worth $119-$149 for a weeklong sail), a free Ultimate Beverage package ($54 per day), up to $300 in onboard spending money, and free gratuities. And on certain voyages, the third through eighth guest in each suite sails for free. If a suite isn't in your budget, you'll still receive a reward for booking with the line -- guests who book an oceanview, balcony, or mini-suite can choose one of the above offers. For a six-night Bermuda cruise from Boston, inside cabins start from $569 and suites start from $1,999. For a six-night Bahamas and Florida trip from New York, oceanviews start from $909 and, Haven rooms start from $2,999. To book, check out this Specials page and click the "view all dates and prices" button to see the individual offers.

It isn't too late to book a cruise in Alaska this year. Alaskan Dream Cruises, the small-ship cruise line based in Sitka, Alaska, is offering up to 10 percent off its May cruise itineraries if you book before March 20. On eight sailings, ranging from four to 11 days, three small-ship vessels accommodate no more than 58 guests and cruise into small coves that big-ship passengers never see. New for this year is the four-day Glacier Bay Quest, in which cruisers spend a full day in Glacier Bay National Park and Preserve, learning insights from a National Park Ranger and a Tlingit Cultural Heritage Guide. The new itinerary is priced at $1,399 per person, without the discount, which varies based on departure.

Looking for a luxe, nature-focused experience this year? Birding, diving, wellness, and photography are among the new theme cruises that Silversea Expeditions is launching this year. Designed for bird enthusiasts, the Birding & Ornithology voyages give cruisers the chance to see bald eagles and blue-footed boobies in the Galapagos and Alaska. On Diving Expedition Voyages, get up close to the remote atolls and the mesmerizing underwater worlds of Indonesia, Micronesia, Melanesia, and Polynesia. And if you're all about nurturing the mind and body, the Wellness itineraries in Southeast Asia and the South Pacific provide plenty of fitness training, yoga, Pilates, daily lectures, and nutrition-centric cooking demonstrations.