Entertainment

Yawny Depp

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“Pirates of the Caribbean: On Stranger Tides.” (AP)

Cutlasses flash, music swells, mast sways, critic yawns. Sure, “Pirates of the Caribbean: On Stranger Tides” be a lusty yarn of the waves. And ’tis as average as the sea is deep.

“Pirates” 4 is not as bad as “Pirates” 3. (Some other things that are not as bad as the 2007 excursion, which by coincidence was also 2007 minutes long: rickets, gangrene, intermediate-stage leprosy.) The previous entry had a habit of pitching and yawing on waves of exposition (“Parley!” usually signaled time to go out for a beer, and maybe not come back, as minutes of screen time were spent quibbling over some footnote in the pirate rulebook). The exposition problem this time is less irritating but still present.

When the explication lets up, the action scenes and banter meet minimum acceptable blockbuster standards, but that’s all you can say for them. Captain Jack Sparrow (Johnny Depp) has an amusing entrance in disguise as a judge who rules on the case of his sidekick Gibbs (Kevin McNally). In a typical example of the movie’s half-baked thinking (which starts with the title — meaningless but cool-sounding, like the name of a cologne), Jack sentences Gibbs to death, then hops into his prison carriage with him, promising that both will escape because a guard has been bribed.

Wouldn’t it have been easier to just find Gibbs innocent and walk away with him? No, because we need for Jack to be double-crossed and hatch a crafty escape. This involves swinging on a chandelier and running across a buffet table set for the king of England, who wants to put Jack under the direction of his old nemesis Barbossa (Geoffrey Rush) on a mission to find the Fountain of Youth before the Spaniards do.

Fleeing like a Looney Tunes Errol Flynn, Capt. Jack runs into his father (Keith Richards), who offers more exposition: You need two silver chalices to drink from the Fountain of Youth. Richards is as wasted here as he was in about 1975: You’ve got two of the most charismatic entertainers of the last 50 years and all that happens is a little back-story delivery? Watching these two performers have a sandwich together would be vastly more entertaining than the movie.

Meanwhile, a rival, ersatz Jack Sparrow is hiring a crew to go after the Fountain, and after a comical sword fight the phony Jack turns out to be his old girlfriend Angelica (Penelope Cruz). It isn’t hard to see what the attraction is: Think of all the mascara secrets they must share. A drawback is that her dad is Blackbeard (Ian McShane), who is to other pirates what pirates are to clergymen. Sparrow leads a goofy mutiny against Blackbeard, yet the old captain keeps him around to help find the Fountain.

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The jokes bob along at a fourth-grade level: Jack calls His Highness “your heinie” and during an argument that involves a Christian proselytizer, says, “I support the missionary position.” The attention span in the story is also more middle school than midshipman: The officers on Blackbeard’s ship are said to have “Zombiefied,” though nothing ever comes of this, and Blackbeard can do magic but apparently prefers not to. He does a couple of nifty tricks when we first meet him and then no more reference is made to his dark arts.

I suppose you have to give credit to the movie for coming up with some badass killer mermaids. As photographed from underneath, their swishing tails are spectacularly sinister — Jaws meets Ariel. But most of the sword fights and other set pieces lack excitement. Director Rob Marshall, who did the musicals “Chicago” and “Nine,” seems to think that Broadway-style fakery is good enough. I picture the actors being told, “Look, just dash around knocking swords together for a couple of minutes. We got Hans Zimmer to score this thing, he’ll make it seem thrilling.” Nameless interchangeable extras — we don’t even see their faces — tumble like autumn leaves as the principals parry and thrust. The music goes DUNT DUNT DUNT.

And the love story goes CLANK CLANK CLANK. The missionary, played by an Orlando Bloom-ish cover boy named Sam Claflin, falls in love with one of the mermaids, and while making goo-goo eyes they ladle out offerings from the Fountain of Cliché.

The first “Pirates” was one of the finest blockbusters of the decade, and the second one wasn’t bad. But it’s the newest episode that made me feel like a kid again — bored, stuck, waiting for something more interesting to come along.

kyle.smith@nypost.com