Some of the world's best surfers were up to the challenge in challenging conditions in the O'Neill World Cup of Surfing yesterday.

The second day of the four-day contest was run yesterday in big and unpredictable waves of 8 to 12 feet (based on traditional heights).

"It's like a big washing machine out there," said North Shore surfer Nathan Carroll. "Local knowledge still helps a little bit, but on a day like this, it's basically like survival."

Carroll was one of six Hawai'i surfers to advance through the fourth round. The others were Makua Rothman, Roy Powers, Kainoa McGee, Bruce Irons and Sean Moody.

"The guys who surf here the most are still going to have an advantage," McGee said. "But it's more or less about getting the right waves at the right time, and anybody had a chance to do that today because it was so hard to tell which waves were going to line up."

As proof, surfers from all over the world took turns winning heats yesterday.

Twenty-six surfers advanced through the fourth round yesterday. In addition to the six Hawai'i surfers advancing, there were eight from Australia, five from Brazil, three from California, and one each from Florida, Portugal, South Africa and New Zealand.

Maz Quinn of New Zealand received a near-perfect 9.83 for a barrel ride, and his two-wave total of 17.66 is the highest of the contest so far.

"There's nothing like this back in New Zealand," Quinn said of the conditions. "My game plan was to sit deep and wait for a good one, and I guess it worked out."

The top seeds in the contest received byes yesterday. Among the top seeds are three-time former world champion Andy Irons of Kaua'i, and defending Triple Crown champion Sunny Garcia.

The World Cup is the second of three events in the Vans Triple Crown of Surfing.

Pancho Sullivan, who won the first event last week, also drew a bye yesterday.

The contest could continue today, if conditions hold. For daily status, call 596-7873 or visit triplecrownofsurfing.com.

Reach Dayton Morinaga at dmorinaga@honoluluadvertiser.com.