When the D'Oyle Carte Opera Company -- the sainted, if somewhat hidebound, home of Gilbert & Sullivan's operettas for 107 years--folded permanently in London last month, Margaret Thatcher's economic pincers were generally viewed as the murder instrument. Still, one wonders if the D'Oyle Carte's venerable foundations hadn't also been rocked a bit by energy emanating from this side of the Atlantic.

Specifically, from the New York Shakespeare Festival's production of "The Pirates of Penzance," which opened a six-week touring engagement at the National Theatre last night. Vigor is its middle name, and quite possibly its first and last, too. This is one of those tradition-defying stagings (the festival's "Much Ado About Nothing," set in Teddy Roosevelt's America, was another) that simply blow away all the cobwebs in the initial moments of gusty irreverence and then proceed to lay out the work on entirely new terms. So much for the usual well-bred, tinkly charms of G&S.

These pirates are bold, bumbling buffoons, who aren't above picking a fight with the members of the orchestra. The pusillanimous constabulary that confronts them in the second act has been schooled by Mack Sennett. And the moonlit maidens, usually all atwitter at the mere notion of matrimony, are gangly, giddy creatures, who have clearly foresworn the traditional graces, if ever they possessed them to begin with. The plot isn't much--merely the idiocy that ensues when an apprentice pirate attempts to take leave of the ragtag crew on his 21st birthday. But if you were to cross an Errol Flynn swashbuckler and an early episode of "Laugh-In," you might find yourself with a hybrid not unlike this "Pirates."

That said, there are a couple of drawbacks to the version at the National, and while they shouldn't be viewed as too discouraging, they must be taken into account. The acrobatic vim is often purchased at the expense of Gilbert's lyrics, approximately half of which are lost in the to-do. William Elliott has provided some strapping adaptations of Sullivan's music, and they are anything but stinting on the trombone slur, the cymbal crash and the "barrroooom" of the big bass drum. In the running byplay between the cast and the orchestra, in fact, one maiden is so startled--and vexed--when a particularly loud boom nearly knocks her off her pins that the drum player actually shows her his score by way of vindication. Literate lyrics do not stand much of a chance in such a climate.

Even when the orchestra is--shall we say--minding its manners, the singers do not always give the impression they would defend their diction to the death. With his lambchop whiskers and his ruddy cheeks, Leo Leyden is certainly "the very model of a modern Major-General," but he could well be chanting in Swahili for all the muddled words that get through. The vocal sloppiness is more or less a general curse, avoided (in the measure that it is avoided) only by Peter Noone, once Herman of Herman's Hermits and here the naive pirate born on Leap Year Day, which makes him officially 5; by Marsha Bagwell, his plump nurse; and by Caroline Peyton, his pristine lady love. As for the duets, trios and choral numbers, you will have to content yourself with the sprightly melodies alone.

In New York, much of the appeal stemmed from the initial conception of the show as a melting pot of eclectic talents, among them Linda Ronstadt, Rex Smith, George Rose, Patricia Routledge and Kevin Kline. The very casting guaranteed a "pop" flavor. Besides Noone, James Belushi gets top billing at the National as the accident-prone pirate king, and while he is a competent and often engaging performer, it is his eerie resemblance, in style and spirit, to his late brother, John, that is most noticeable under the circumstances. Some authentic star power wouldn't hurt this production. Otherwise, "Pirates" is a rowdy, rambunctious evening that delivers much of the exhilaration of a good pillow fight. Director Wilford Leach has decked the slender story with all manner of preposterous byplay. Gilbert & Sullivan were mocking the Englishman's suffocating sense of duty, and Leach enjoys knocking a stuffed shirt as much as the next man. But he also takes great glee in mocking the theater itself. When one of the dancing policemen sinks into a split, you can be sure he will momentarily get stuck to the floor in a pose of splayed agony.

From the very outset, as the pirates' galleon heaves into view, this show simply refuses to stay put. The pirate king's furious, but ill-aimed, rapier thrusts are enough to keep all those with vaguely self-protective interests alert and hopping. When Belushi scores a hit, it is, unfortunately, on his own foot and he has merely succeeded in pinning himself briefly to the spot. The pirates' second-act raid degenerates into a me le'e that encompasses the orchestra again, some members of which are pre-armed with water pistols. Even Noone, a spindly whelp, works in the subtle gyrations of the rock idol in his otherwise high-toned appeal to the loftier side of seven obviously panting maidens ("Oh, Is There Not One Maiden Breast"). The results are entertainingly frenetic.

With such an abundance of antics, it may seem like carping to object to the loss of some words. But words can be funny, too. Especially when the patter is flowing from Gilbert's equally antic pen.

THE PIRATES OF PENZANCE. By Gilbert & Sullivan. Directed by Wilford Leach; music adapted by William Elliott; choreography by Graciella Danielle; scenery, Bob Shaw and Wilford Leach; costumes, Patricia McGourty; lighting, Jennifer Tipton. With James Belushi, Peter Noone, Marsha Bagwell, Wally Kurth, Leo Leyden, Caroline Peyton. At the National Theatre through May 2.