Luxury cruise ships with butlers, walk-in wardrobes and submarines

Luxury cruising has changed dramatically from the days when it consisted of staying in the best suites on a swanky ship with a chance to meet the captain. The upper end of the market is diverging in many directions, an early adopter of innovations in design and technology, with attempts being continuously made to redefine what luxury means.

Larger ships are offering ever more extravagant touches for their high-paying guests: butler services, cabins with walk-in wardrobes, private plunge pools and decks, and private chefs. Even on standard cruises the quality of the uppermost cabins matches that of a five-star hotel suite, and many ships have added VIP areas.

At the same time, there’s a trend for small, chic, exclusive vessels that deliver an experience similar…