I never actually got to see the best dish I tasted during a four-day cruise through the Western Caribbean. I was wearing a blindfold, tomato broth dribbling down my chin, as I bit into a chunk of red snapper with a delectable salty sear. The concept of eating food that you can’t see — dark dining — has met with moderate success in restaurants from Paris to Bangkok, but it was directly at odds with the excursion’s branding.

… That misstep in programming was an example of the difficulty of translating a creative commodity — a band, a television show, a film genre — into an itinerary that stretches for days. Yet the themed cruise is increasingly the way that lines try to entice new passengers. There is no accounting for how many themed itineraries are being offered to the 20 million passengers that the Cruise Lines International Association expects this year, but spokesmen for the group and the Cruise Critic travel news site say themed excursions are on the rise.