The cruise industry keeps outdoing itself. No sooner does one company introduce a ship with a lineup of new features, innovative use of deck space and a celebrity chef partnership than another ship is on the drawing board with another new dining concept, new family stateroom configuration, new amazing waterpark.

The speedy advance of shipboard features for a line’s flagship class leaves the line with a perennial problem: what to do about the older vessels in the fleet. How do cruise lines update ships that were designed at great expense and often refurbished but don’t have the new bells and whistles, or were built during an era of cruising when tastes and priorities were different?

The issue can affect the company throughout: Being able to train and move crew effectively between classes of ships, for example, or in sales and marketing.

Each line deals with fleet upgrades in different ways, depending on the need — from individual ship refurbs to multiship programs like Carnival’s Evolutions of Fun and Holland America’s Signature of Excellence — and one way is to bring the best of the new innovations to the older ships and make them into brand standards.

Take Celebrity, for example. The Celebrity Solstice debuted in 2008 to a storm of praise and a slew of new features: The “clean cuisine” at Blu, the AquaClass category of suites, the creperie called Bistro on Five and the Lawn Club with real grass, to name a few.

Celebrity’s Millennium class, meanwhile, is separated from the Solstice by about eight years. The 2,000-passenger Millennium ships are different from their modern sister ships because of their size and because, simply, they were constructed when different trends were in vogue.

The ships had a main dining room and an alternative-dining restaurant for the special-occasion night, serviceable bars (martini bar on the port side, champagne bar on starboard), a cigar bar, a linear lido buffet restaurant, an Internet cafe. There were three levels to the evening dress code.

In January 2010 then-CEO Dan Hanrahan revealed the plan to import the best of the Solstice innovations to the Millennium ships during three-week drydock periods, and introduced the term “Solsticize” as a verb and industry buzzword.

Greg Purdy, Celebrity’s senior vice president of operations, last month talked about some of the reasoning behind the Solsticizing of the older vessels.

“I think what we did — we know we’re not going to get a Solstice-class ship — [was] to make sure the ships are relevant and attractive to the market we’re going after,” he said.

“You’ll feel like you were with the brand you were marketed to.”

The Summit experience

On a cruise aboard the 12-year-old Summit this summer, the melding of old and new seemed consistent. If I hadn’t studied an old deck plan, and had memories of sailing on the Constellation, several years ago, to guide me, I probably wouldn’t have known that the Bistro on Five had been carved out of a former lounge, or that Qsine hadn’t always been in its space on Deck 11.

In fact, occasionally, a few of the Solstice amenities seem better situated on the Millennium-class ships, Purdy said. Qsine was a perfect example: With the room’s “dramatic” high ceilings and tall, windowed walls that look out to the top deck and over the ocean, guests are treated to a stellar view (see related report, “In dining, whimsy vs. refinement.”).

Some of the innovations in traffic patterns can’t be replicated on an older ship without tearing the footprint out completely. There’s no getting around the linear setup of the Oceanview Buffet, which had some, but not all, of the same food offerings on its port and starboard counters.

I’d brought my young daughter, so I was ineligible to stay in the adults-only AquaClass. On the Solstice these cabins are located on the deck below the spa, but on the Summit the cabins are located aft; the spa, far forward; and Blu, the exclusive restaurant with its own design scheme, is a carve-out of the main restaurant.

The Martini Bar in the ship’s atrium appeared to be a clear winner: It was set into a windowed alcove and featured a solid menu of drinks, from fancy cocktails to the familiar standards, expertly poured.

One thing that Solsticizing does is sharpen some of the spaces that previously were less defined or less trafficked. For example, the Martini Bar, which Purdy said “livened up that whole central atrium area.”

Bistro on Five was a pleasant change from dinner in the large Cosmopolitan dining room, and the menu of crepes was unique. The design of the room was fresh and modern. Its presence also leaves the adjacent Cellar Masters with a more defined space. One fun feature here is a wine dispensary where cruisers can swipe their cards for a measure of wine (bartenders are also on hand).

The Summit’s iLounge, on Deck 6, isn’t as striking as the Apple displays on the Solstice ships, which are on view in the main atrium.

However, the ship is WiFi-enabled now, so cruisers are able to use their MacBooks aand PC laptops throughout the vessel. They can shop for Apple products at the store in the Galleria shopping zone separate from the iLounge.

Some things onboard just change over time, regardless of Solsticizing. Michael’s the cigar bar is now Michael’s the craft beer bar (cigars can be purchased and smoked at the outdoor bar behind the Oceanview).

And other interesting Solstice favorites aren’t on the older ships. I was disappointed that there wasn’t a Lawn Club, for example, which I thought could have been a great add to the Summit’s forward top deck.

Of course, not every bar and lounge and blade of grass can make the final cut during a Solsticizing, and Purdy said that the line makes decisions based on, among other things, amount of drydock time available, perceived return on investment and what they think will be “the best for the experience” — it is a business, after all.

The retrofit also added cabins to the Millennium-class ships. But Purdy emphasized that the return isn’t necessarily all based on bottom-line dollars and cents.

“The bigger kind of return is that we can market all our ships more cohesively, and ticket prices [are] more cohesive,” he said, “having the iconic venues to make it a more cohesive fleet.”