Andriana Chuchman as Magnolia and Michael Todd Simpson as Gaylord Ravenal in the Washington National Opera’s production of “Show Boat.” (Scott Suchman)

I was on the fence about “Show Boat” when I sat down at the Kennedy Center Opera House on Saturday night, and I was still on the fence after the first 15 minutes or so of Francesca Zambello’s production. Don’t get me wrong. I have no problem with the idea of opera companies staging American musicals. Indeed, I find it pretty hypocritical to criticize it, given that most people who wring their hands at the sullying of the operatic temple would sit through “Die Fledermaus” or “Daughter of the Regiment” without any problem at all, as if light entertainment is all right as long as it’s in another language. My reservation has been that I don’t think opera companies always do a very good job of it.

So the show started, and there were the nice tunes in the overture, sounding a little slender but perfectly acceptable under the baton of John DeMain. And then the curtain went up and almost right away we had a stage filled with a zillion people (“More than 100!” promise the ads), sliding sets (by Peter J. Davison) and a lot of frenetic activity. It’s the frenetic part that makes me crazy. I tend to think operatic acting is going downhill anyway, because many in this new generation of singing actors simply run all over the stage, thinking this is “naturalistic” behavior, while ignoring every acting technique in the book. And oh, was this true of “Show Boat’s” spoken dialogue — stilted, shouted, mugged. Zambello, in Wagner’s “Siegfried” a couple of years ago, created one of the most memorable evenings of drama I’ve ever had in the theater. Why can’t she get singers to do better with spoken dialogue in their own language?

And then Morris Robinson sang “Ol’ Man River,” and finally, I got it. I can’t say that Robinson gave the most breathtaking performance of this song I ever heard, because Paul Robeson is indelibly embedded in my ear, and Robinson’s sound is a little thinner, a little more pushed or shoved up than that. That doesn’t matter, though, because he sang a really good “Ol’ Man River,” and because when I heard it, it was so clear what a cornerstone this song is of our shared musical heritage. All the European opera-lovers I know get to hear at least some music that has some resonance with their own culture; here’s music that speaks of ours, pretty profoundly, in a work that is every bit as worthy as plenty of operas in the standard canon. Here’s why Kern and Hammerstein’s “Show Boat” belongs in an opera house, especially an opera house bearing the word “national” in its name: It gives you a chance to connect the dots and get our own musical heritage into the picture.

And it gives you a chance to savor that heritage. “Show Boat” has gone through a bunch of different versions, in a bunch of different productions, but this three-hour version — a co-production by the Washington National Opera, the Lyric Opera of Chicago, the Houston Grand Opera and the San Francisco Opera Association — includes several songs that aren’t always performed, including “Till Good Luck Comes My Way” and “Mis’ry’s Comin’ Round.”

Another reason this “Show Boat” deserves to be presented alongside operas: The acting and storytelling came through much better in the singing than in the speech. The two female leads, Andriana Chuchman as Magnolia Hawks and Alyson Cambridge as Julie, offered toe-curling, squeaky, Minnie-Mouse-style dialogue (the “Southern” accents didn’t help). But their singing was terrific. Cambridge stopped the show when Julie, washed-up and alcoholic after the revelation of her African American heritage ends her career on the show boat, gave a devastating rendition of “Bill.”

And Chuchman had a full, sure, glorious sound you wanted to sink into. When she and Michael Todd Simpson, as Gaylord Ravenal, sang their first duet, all of the characterization was clear in the music. He was a suave wannabe, superficially appealing but not enduring. And she was a person of warmth and substance and heart. I’m not sure this was entirely deliberate, but it didn’t really matter, because it worked.

Angela Renee Simpson, as Queenie, showed a pitfall of casting an operatic voice in this repertory: The part calls for a big, belting voice, and belting is not an arrow in Simpson’s quiver, which made for an incongruously delicate portrayal. Robinson, by contrast, sounded as much at ease as Joe as in any Met role. Both he and Simpson were also quite a bit better than some of their colleagues at the spoken dialogue, despite being saddled with some pretty dated material about shiftless no-count men and so forth; they communicated a genuine warmth and affection. “Show Boat” is about race relations, but it’s also about the ups and downs of long-term romantic relationships — a welcome change from most musicals, which tend to follow romance just as far as “happily ever after.”

Counterbalancing these two opera singers were the actors Lara Teeter and Cindy Gold as Capt. Andy Hawks and his wife, Parthy Ann. Teeter initially seemed wearingly overdone but gradually won me over. Bernie Yvon and Kate Loprest did just fine as the musical-buffa couple of Schulz and Schulz, Loprest with a nasal touch presaging Adelaide in “Guys and Dolls.”

The opera-house musical productions I’ve seen are never quite certain how far they want to go in the Broadway idiom, and this one was no exception. The two biggest issues are amplification — a dirty word to opera audiences — and dancing. It sounded as if amplification was used in moderation, notably in the scenes with Magnolia and Gaylord’s young daughter, Kim (a nicely straightforward Maya McGuire), but not enough to keep the singers from screaming their lines. And the dancing was provided in big production numbers that still felt a little restrained, not quite as over-the-top as their Broadway counterparts, for all of the stage-filling spectacle (though the dancers there were did yeoman service). No matter. Miking or not, this “Show Boat” was worth the ride, and I for one was grateful it came here, and happy when I left the theater.

“Show Boat” continues through May 26, with alternating casts, at the Kennedy Center Opera House. Rodney Gilfrey has withdrawn from the second cast; casting of Gaylord Ravenal for those performances is pending.