It’s hard not to sympathize with "Capt. Crowther," played by Sid James, when he realizes that several of his crew members have become ill and the new ones seem completely lost, unsure even of which ocean they're navigating. However, his difficulties don't end there; the passengers aboard the SS “Happy Wanderer” are a group so eccentric they’d probably cause an iceberg to avoid the "Titanic." As is typical, Esma Cannon truly shines as the spirited and slightly confused "Miss Madderley," and Liz Fraser, Ronnie Stevens—who seems perpetually inebriated—and Kenneth Williams, portraying the unfortunate second-in-command, also deliver noteworthy performances. The humor consists of familiar nautical jokes filled with suggestive remarks (although I’m not certain I detected the phrase “avast behind”), and it's clear that the cast is having a good time as the narrative follows its expected, yet enjoyable, trajectory. While I believe the "Carry On" films were more effective in black and white—the comedy felt rooted in the past rather than looking toward color—this one satirizes cruising culture: snobbery, extravagance, monotony, and the middle-class passengers who often filled the cabins while overindulging in unfamiliar cocktails, and it manages to do so quite effectively. It’s more of a chuckle than a full-blown laugh, but is supported by some clever writing and the performances of James and Williams.

Source on TMDB