Producers: Andrew Lazar and Teddy Schwarzman   Directors: Elizabeth Chai Vasarhelyi and Jimmy Chin   Screenplay: Julia Cox Cast: Annette Bening, Jodie Foster, Rhys Ifans, Ethan Jones Romero, Luke Cosgrove, Jeena Yi, Eric T. Miller and Karly Rothenberg  Distributor: Netflix

Grade: B-

Annette Bening and Jodie Foster make a formidable pair as marathon swimmer Diana Nyad and her best friend Bonnie Stoll in this adaptation of Nyad’s 2016 memoir “Find a Way” about her attempts, after she’d turned sixty, to swim the hundred-and-ten miles from Cuba to Florida—a feat she’d failed to accomplish when she first attempted it in 1978 when she was twenty-eight, and which no one else had managed since.  It was only on her fifth attempt in 2013, after three more unsuccessful ones in 2011-2012, that she completed the journey at age sixty-four.

The sports drama, co-directed by the celebrated documentarian team of Elizabeth Chai Vasarhelyi and Jimmy Chin (“Free Solo”), proves more exhausting than exhilarating, but in a way that’s the point.

In fact as portrayed by Bening, Nyad is an exhausting person—single-minded, self-centered and domineering.  Of course she’s also an extraordinarily impressive athlete who, as shown in periodic flashbacks, as a youngster not only survived being molested by her coach (Eric T. Miller) but overcame the trauma to become a star of marathon swimming; and her skill in self-promotion was no less remarkable.

But she’s not the only strong woman in this story.  As played by Foster, Stoll is as self-effacing and supportive as Nyad is arrogant and demanding, but every bit as important in her friend’s ultimate triumph, taking charge when even Nyad seems ready to give up.  And the fact that the film boasts two impressive lead performances gives it the impetus it needs.

That’s because in the reality the plot is very simple, and quite repetitive.  As she reaches a milestone birthday Nyad, agitated by the fact that her life has become so sedate (playing Scrabble with Stoll a highlight of the week), decides to try something long thought impossible and begins solitary training.  When she reveals her plan to Stoll, her friend simply wants no part of it.  Naturally she relents, though reluctantly.

Once they agree, they have to assemble a team for the attempt.  The most important member is John Bartlett (Rhys Ifans), an old salt whose knowledge of currents and weather will prove invaluable, if they can convince him to join the venture.  Fortunately he does, and he’ll remain an integral part of the team to the end, though there will be rough patches, including a health issue toward the close.  Other team members will include Dee Brady (Karly Rothenberg), Angel Yanagihara (Jeena Yi), Nico (Ethan Jones Romero) and Luke Tipple (Luke Cosgrove); they’ll be active in adaptations made over the multi-year course of the project, like methods of warding off shark attacks and jellyfish assaults.  All of the actors bring energy and understandable concern to their characters, though none come into the sharp focus given to Bening, Foster and Ifans.

Julia Cox’s screenplay follows Nyad’s memoir closely in detailing each of the four attempts, so that viewers can share the team’s moments of exultation, danger, disappointment and ultimate celebration.  There are, of necessity, prolonged episodes of Nyad—or either Bening or (perhaps) a double—doing strokes in rough waters.  And there are bursts of bad weather, of course.  All of this is handled well not only by the cast but by the technical crew—in particular production designer Kara Lindstrom, cinematographer Claudio Miranda.  But while Vasarhelyi and Chin, as well as editor Christopher Tellefsen, is obviously dedicated to telling the story in a straightforward, dedicated fashion, they can’t entirely overcome a feeling of going over the same plot beats repeatedly.  Still, Alexandre Desplat’s score (along with some interpolations of contemporary pop) helps by to keep things moving over the longueurs.

The film ends, predictably, on a note of complete triumph, without noting that, because of a variety of factors, neither the World Open Water Swimming Association nor any other “official” group has recognized Nyad’s swim in their ledgers of record accomplishments.  Still, there’s no sign that the omission has dampened the enthusiasm of Nyad and her supporters, at least if the archival clips predictably added to the final credits are any indication.