As our massive vacation vessel gently bobbed its way through the Caribbean, hundreds of nostalgic baby boomers crammed into a theater and basked in Justin Hayward's mellifluous, symphonic pop.

The Moody Blues songwriter promised a "trip down memory lane" with his headlining set aboard the recent inaugural On the Blue Cruise, and he delivered – cycling through the group's sprawling songbook, stripping down the lavishly arranged tunes to voice, two folky guitars, flute and keyboard.

With Cruise to the Edge, the flagship floating prog event from production company On the Blue, surprise and provocation is often half the fun. But on this voyage, Hayward's aim felt more like the norm: Kick back in your theater chair, order a glass of wine, hold your hubby's hand, maybe reminisce about senior year.

Given the median age of the performers on board, the set lists veered toward the '70s – and it was a hit parade of all varieties, from Poco's breezy country-rock ("Crazy Love") to Vanilla Fudge's proto-metal cover versions ("You Keep Me Hangin' On") to Alan Parsons' art-pop staples ("Eye in the Sky") to Procol Harum's elegant symph-rock ("A Whiter Shade of Pale").

Even the between-song chatter leaned retro: During his lovely late-afternoon theater set, singer-songwriter Al Stewart reflected on how King Crimson maestro Robert Fripp once gave him guitar lessons at age 15. And in a heartwarming nod to their early days, psych-pop icons the Zombies brought out their original bassist and drummer -- Chris White and Hugh Grundy, respectively -- for the final moments of their encore.

At times, all that winking to the past came off as awkward – drop in on a random set, and you'd most likely hear phrases like "Who remembers 1975?" or "Clap along if you know this one" at any given moment. But that was also part of the cruise's distinctive charm: Unlike most on-land festivals, nobody here was trying to look cool, and everyone was on board for the same sense of camaraderie. So what if you heard a few more dad jokes than you would at Coachella?

Still, the edgiest performances stood out from the pack. Steve Hackett, a Cruise to the Edge veteran who literally got off that ship the day before, continued to mine the Genesis catalog with one eye toward the future. Woodwind ace Rob Townsend breathed new life into some of prog-rock's essential cuts, including "Firth of Fifth" (highlighted by his buttery-smooth saxophone solo) and the 23-minute "Supper's Ready."

Parsons admirably peppered in a handful of glossy new songs, like "Miracle," throughout his sets, and when Todd Rundgren dove into rock history, he did so with tongue in cheek and one-liners at the ready: "A little song, a little dance, a little Seltzer down the pants," he promised, before launching into goofy takes on Melanie's soft-pop tune "Brand New Key" and Fraternity of Man's country-rock weed ballad "Don't Bogart Me."

The cruise's most breathtaking moment was one of its underdog moments – one of several pool stage sets that most people skipped in order to catch a more famous headliner. Strawbs, the folk-turned-prog legends – and the lineup's clear wild-card selection –  thundered through some of their proggiest anthems, including selections from LPs like Hero and Heroine and Ghosts.

Unless you count the euphoric singalong "Lay Down," a marginal U.K. hit, we were oceans away from the pop charts. But no one gathered there, lined up in folding chairs amid the biting wind, seemed to care one bit.



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