Gerard Butler in the Surfing Movie "Chasing Mavericks" John P. Johnson/20th Century Fox Gerard Butler, left, and Johnny Weston in "Chasing Mavericks," which celebrates Jay Moriarity, a famed surfer of Mavericks, a treacherous zone in California. Early on the morning of Dec. 19, 1994, a surfer named Jeff Clark stood alongside a few friends on a high bluff just outside Pillar Point Harbor in Half Moon Bay, Calif., watching 40-foot waves crash onto the reef at the big-wave surf spot known as Mavericks. The offshore winds were dangerously gusty, and Mr. Clark, 37, who had been surfing there for two decades, felt it prudent to wait for them to abate. Several of his friends were already in the water. Among them was Jay Moriarity, 16, who had only surfed Mavericks a few times and was the youngest person Mr. Clark had ever seen challenge the spot. When the biggest wave of the morning swept in, Moriarity paddled hard. But as he rose to his feet, the wind lifted his surfboard into the air like a kite. He fell the equivalent of five stories and was driven 40 feet underwater. On a boat at the edge of the surf zone, the photographer Bob Barbour watched in horror. "I thought I was going to have to call his mother and tell her that her son had died," he said in a phone interview. After a tense half-minute Moriarity kicked off the sea floor, swam to the boat to grab a replacement for his broken surfboard and paddled back out. An astonished Mr. Barbour would capture what is generally considered the greatest wipeout in the sport's history, not only placing Moriarity on the cover of Surfer magazine but also more recently on billboards promoting the new film "Chasing Mavericks." It is an account of the life of Moriarity, who died at 22 in a diving accident, and his relationships with his girlfriend and eventual wife, Kim, and his mentor, Rick Hesson, called Frosty. Moriarity's fearless surfing and warm personality made him a hero and a favorite son in Half Moon Bay, and his hometown, Santa Cruz. Mr. Hesson, Mr. Clark, Mr. Barbour and others say that the film's directors, Curtis Hanson and Michael Apted, and two of the producers, Brandon Hooper and Jim Meenaghan (who both happen to be surfers), have achieved something as rare as Moriarity's wipeout: an accurate Hollywood portrayal of surfers and surfing. Mr. Hooper said he saw universal appeal in the alternately uplifting and tragic tale of Moriarity's friendship with Mr. Hesson, but was acutely aware of the longstanding trap of inauthentic Hollywood takes on surfing. There was Mickey Muñoz's bikini-clad stunt doubling in the 1959 "Gidget"; laughable projected backdrops in "Ride the Wild Surf" from 1964; surfers who inexplicably reverse their board stances in "Point Break" (1991); and the computer graphics that enhanced Kate Bosworth in "Blue Crush" (2002). "We said, "We've got to capture big-wave surfers with big-wave surfers," " Mr. Hooper recalled in a phone interview. "I mean, we've seen "Blue Crush," where the girl's surfing and all the sudden it's clearly a guy in a bikini." The filmmakers went ahead and cast the nonsurfers Gerard Butler as Frosty and the newcomer Johnny Weston as Jay, yet they also employed the San Francisco film editor and Mavericks surfer Grant Washburn to assist the water-photography director Philip Boston in coordinating a collection of renowned ocean stuntmen and safety experts. Mr. Washburn, who produced his own PBS documentary on Mavericks in 1998, was later asked to aid in the editing of the film's water scenes. When it came time to cast Mr. Hesson's contemporaries, a group Mr. Hooper called the Magnificent Three, Mavericks regulars read for the parts, which went to three of the best in the big-wave world: Zach Wormhoudt, Greg Long and Peter Mel. When Mr. Mel auditioned, he wanted the filmmakers to understand the situation. "I said, "Excuse me, before I read a couple of lines, can I say a few things?" " he recalled telling them. " "This is very important to me, and it's very close to me. This is the town I've grown up in for 40 years. This surf spot that has created my career, and Jay's story, are very, very close to me. Please pay attention to every detail, and please make sure you listen to the people in this community." " Mr. Hooper said he was initially intimidated by the surfers. "These guys, they're animals," he said. They drop into 50-foot waves. But he added that in person: "They were so polite, concise, helpful and professional. There weren't egos at play. It was all for Jay and getting it right. Mr. Washburn, who essentially moved to Los Angeles to help with months of postproduction, said in Half Moon Bay that the surfers involved in the film were impressed by the crew and actors, particularly Mr. Butler and Mr. Weston, who endured grueling workouts and scenes in the perilous waters around Mavericks. Mr. Butler narrowly survived a smothering hold-down by four successive waves, an incident Mr. Mel called "the real deal." Several of the film's surfers said that they hoped "Chasing Mavericks" comes close to the surf movie they admire most: John Milius's 1978 drama "Big Wednesday," which followed three Malibu friends from the 1960s through the Vietnam War. A box office dud, it finally resonated a decade later (when it reached VHS) with nostalgia-hungry surfers. Despite some noticeable discontinuities in the surf scenes, Mr. Milius's own life as a surfer and the real surf experience of the stars, Jan-Michael Vincent, William Katt and Gary Busey, gave the film its authenticity. Still, not everyone is convinced that "Chasing Mavericks" will reach a benchmark. Sam George, a writer of the surf documentary "Riding Giants," recently completed another documentary whose title says it all: "Hollywood Don't Surf!" In the film, he said in a phone interview, "we quoted Steven Spielberg as saying that he felt that "Big Wednesday" was going to be John Milius's "American Graffiti," and it wasn't because Milius let his eccentric love of surfing get in the way of essential Hollywood structure and storytelling." Mr. George said that part of the problem was that nearly every surf feature, even the animated "Surf's Up," perhaps the most successful surf film at the box office, features three male leads in "the exact same plotline - the crux that one of the surfers is going to get that last big ride." Frosty Hesson said he hoped that surfers and other filmgoers wouldn't be quick to judge. Despite jaw-dropping big wave footage, "it was never intended to be a surfing film," he said. Like "Field of Dreams" with baseball or "The Blind Side" with football, he said, "Chasing Mavericks" uses surfing to look at relationships."The sport was a medium, but that's not what the story is about, and that's not what made those films compelling."