Because the ship is the only one in Norwegian's fleet that sails to Cuba and also the only one to include a drinking package in all cruise fares, passengers on Norwegian Sky tend to be younger American couples eager to explore a new country unseen by many in the U.S. Families are rare -- especially for Cuba itineraries -- though children are more common during the summer and around holidays when school is out. Additionally, the ship's three- and four-day cruises are a draw for Floridians who are looking for a fast, fun getaway out of Miami.

Anything goes on Norwegian Sky, which doesn't have formal nights or major dress code rules. During the day, it's swimsuits, cover-ups, shorts, dresses and comfortable clothing, both in port and onboard. At night, you don't have to dress for dinner, though a few restaurants won't allow shorts in the evening (Le Bistro and Il Adagio). On Cuban itineraries, you'll see more than the usual number of straw hats and traditional Cuban guayabera shirts. (If you don't own Cuban clothing, you can pick up new items in Havana.) Pack white clothing if you'd like to participate in the ship's "White Hot Night," a dance/glow party that takes place at night once per cruise.

A daily service charge of $18.99 per person per day is automatically added to the bills for passengers in standard cabins and mini-suites. The rate for suite passengers is $21.99 per person per day. (This is higher than the industry average or even what is charged on other Norwegian ships because of Sky's all-inclusive drinks package.) Passengers who aren't satisfied with service -- and their issue can't be resolved during their sailing -- can ask for a refund of those fees by contacting the line's guest relations at servicecharges@NCL.com once they return home from their cruise. Passengers, of course, can elect to tip additionally for excellent service. In fact, because the cruise includes a beverage package, a number of passengers on our sailings tipped waiters and bartenders $1 or $2 in cash. (This is not necessary, as the cruise fare and daily service fee account for tips, but staff do appreciate it and might expedite future service.)

An 18 percent gratuity also is added automatically for specialty dining and spa and salon services. Except for continental breakfast items, room service comes with a $7.95 service charge. Again, passengers can tip room service stewards an extra dollar or two, but it's not required. Passengers can pay their final bills using cash, or credit or debit cards. Because the sailings are shorter, many passengers settle up in cash, which means the line at guest services on the final day is exceptionally long.