JOHANNESBURG - An acclaimed outdoorsman who wrote movingly about testing himself against nature is presumed dead after a crocodile snatched him from his kayak while he led an American expedition from the source of the White Nile into the heart of Congo.

Two Americans being guided by South African Hendrik Coetzee, 35, on the grueling trip could only watch in horror. They paddled unharmed to safety after the Tuesday-morning attack on the Lukuga River in Congo.

The International Rescue Committee, which runs development projects in the Central African nation, helped evacuate the Americans to a nearby town, Ciaran Donnelly, the organization's regional director in Congo, said yesterday.

Coetzee's body has not been recovered. The stretch of river where the trio was traveling is notoriously dangerous because of its whitewater and the high density of crocodiles and hippos.

In a blog called The Great White Explorer that chronicled the trip sponsored by the Eddie Bauer clothing and outdoor-equipment company, Coetzee wrote about the thrill of taking to uncharted waters, including stretches that might soon disappear because of planned dams. He also described sometimes facing suspicion from military and other officials.

A friend, Celliers Kruger, who owns a South African kayaking company, called Coetzee a legend.

"He was the bravest guy I've ever known," Kruger said. "But he wasn't crazy. He was very calculated and set the bar high for future exploration in Africa."

Coetzee wasn't just interested in the adrenaline rush, said Hugh du Preez, a friend who kayaked with him.

"He also had a fantastic social conscience," he said, adding that Coetzee ran kayak trips for underprivileged kids in Sudan. "He was one of those people that would look after others not only in a physical sense but also nurture them spiritually and mentally."

Eddie Bauer said the trip was a first-of-its-kind kayaking expedition from the White Nile and Congo rivers into Congo. The three men, all experienced kayakers, were documenting unexplored whitewater and development projects in the region.

The two Americans - Ben Stookesberry and Chris Korbulic - are in Congo but expect to return to the United States shortly. Korbulic is from Rogue River, Ore., and Stookesberry, from Mount Shasta, Calif. Coetzee had been living in Uganda at the time of the expedition.

One of the Americans recounted on his blog how Coetzee has warned them about the dangers of the trip, including "three-ton hippos that will bite you in half."

"Stay off the banks because the crocs are having a bake and might fancy you for lunch. Basically, stay close behind me and follow my lead. Any questions?" the blog quoted Coetzee as saying.