The final anchor will be lifted on Captains Courageous, the Musical April 4 at Manhattan Theatre Club.

On March 30, beginning the final week of the run of the Rudyard Kipling based musical, Rich Hebert unfurled his sail, replacing star Treat Williams, who was committed to shooting a movie.

A spokesman said Williams, who played the musical's nurturing Portuguese fisherman, Manuel, is set to begin work on a USA Network movie, "Journey to the Center of the Earth," shooting in Australia, the first week in April.

Hebert, Williams' standby, joined an all-male company for the ensemble show. Brandon Espinoza (Big) plays Harvey Cheyne, the selfish, rich boy fished out of the sea by Manuel.

Hebert's credits include The Life, Sunset Boulevard, Les Miserables, Cats and more. *

Captains Courageous, about life on the high seas (or, at least, off the coast of New England), began previews Jan. 12 and opened Feb. 16 at MTC's Stage I.

In fall 1998, it was speculated that the coming-of-age tuner, one of the New York season's few new musicals, might have a bigger life beyond MTC, but that is not the immediate future for the Patrick Cook (book and lyrics)-Frederick Freyer (score) project. The show's reviews were mostly mixed, with the exception of a rave from The New York Post. A Sony Classical cast album of the show was canceled.

The staging is the New York premiere following a production at the Goodspeed Opera House's Norma Terris Theatre and a 1992 staging at Ford's Theatre, Washington D.C. The musical is based on the Kipling source as well as the motion picture of the same name.

On a rotating turntable set, the all-male cast sings a netful of seagoing chanteys and anthems. The score includes "Out on The Sea," "Little Fish," "I'm Harvey Ellesworth Cheyne," "Not So Bad," "I Married a Woman," "I Make Up This Song," "A Hundred Years Ago," "Goodnight, Sweet Molly," "She Waits For Me," "That's Where I'm Bound," "Jonah," "You Never Saw," "Song of the Sea," "Not This Year," "Regular Fellas" and "I'm Home."

Musical staging is by Jerry Mitchell, whose choreography credits include the Broadway revival of Grease, O pway's Hedwig and the Angry Inch, the national tour of Jekyll & Hyde and the Broadway revival of You're a Good Man, Charlie Brown.

Orchestrations are by Jonathan Tunick (the frequent Stephen Sondheim collaborator), with musical direction by Robert Gustafson. Designers are Derek McLane (sets), Catherine Zuber (costumes), Brian MacDevitt (lighting) and Otts Munderloh (sound).

Treat Williams, known for the films "Prince of the City" and "Hair," and Broadway productions of Over Here, Pirates of Penzance and Grease, originated the Off-Broadway role of the Portuguese fisherman, Manuel, who rescues a rich industrialist's son (Espinoza) from drowning and teaches him about friendship and responsibility.

*

Cook and Freyer have been writing musicals together for more than 10 years. Their musical, Mr. Smith Goes to Washington, was commissioned by Ford's Theatre. Their new musical, 97 Orchard Street, is in development.

The cast includes Erick Buckley, Dick Decareau, Michael DeVries, J. Lee Flynn, Pete Herber, George Kmeck, Norm Lewis, Michael X. Martin, Michael Mulheren, Gary Schwartz, Dan Sharkey, Daniel Siford, Danny Gurwin (replacing Jim Stanek) and Erik Stein.

Williams' other film roles include "The Devil's Own," "1941," "Once Upon a Time in America" and "Mulholland Falls." On TV, he was Stanley Kowalski opposite Ann-Margret in ABC's "A Streetcar Named Desire."

Espinoza has appeared on Broadway in Big, Les Miserables and The Will Rogers Follies. He is currently a student at the LaGuardia High School of the Performing Arts.

Meadow's directorial work includes Leslie Ayvazian's Nine Armenians, Donald Margulies' The Loman Family Picnic, A Small Family Business (Broadway); Absent Friends, Woman in Mind (Drama Desk nomination), Lee Blessing's Eleemosynary and many other plays.

MTC Stage I is at City Center, 131 West 55th St. (between Sixth and Seventh Avenues). Tickets are $50. Playing at MTC's Stage II is Chay Yew's Red. Call (212) 581-1212.

-- By Kenneth Jones