More than 8km and a world of submarine violence separate the 1,500m race from the marathon swim.

The difference is so great that even the world's strongest swimmers seem unable to change lanes from one discipline to the other.

When Russia's Vladimir Dyatchin tried out for the 1,500m for the 2004 Athens Games, one year after winning the marathon (10km) world title in nearby Barcelona, he failed to qualify and packed away his togs for good. Or, so the world thought.

Australia's 1,500m specialist Grant Hackett also came a cropper when he attempted to earn his ticket to the Beijing Games at this month's Open Water World Championships in the 10 km endurance event, which is about to make its Olympic debut.

Hackett, a two-time Olympic gold medalist in the 1,500m, got sucked into the underwater scrimmage and was disqualified.

"Marathon swimming is not one lane, one swimmer, like Grant is used to," said Dyatchin, the 2007 world open water swimmer of the year.

"There are more swimmers, and every time there is fighting, so I think for him it was difficult, and after about 7km he got tired," he said, speaking to China Daily by phone from Seville, Spain, fresh after claiming another world title.

Hackett has qualified for three events in Beijing - the 400m and 1,500m freestyles and 4x200m relay - but he was sorely disappointed at losing the chance to add a marathon Olympic medal to the four he already owns.

Ky Hurst, a former Ironman who would have beaten Hackett to the Oceania qualifying slot in the marathon even without the disqualification, said his teammate was the victim of foul play.

"Unfortunately Grant, having been the ultimate distance swimmer in the world for so many years, he had a big target on his head and they did that, they swum all over him and he got swallowed," he told Sydney's Daily Telegraph.

While the rowing lane used in Seville was not very different from the Beijing Olympic venue at Shunyi, sea-swum marathons are a different kettle of fish.

Athletes have to contend with currents, tides and sometimes jellyfish on top of muscle cramps, hunger pains, tricky feeding pontoons - and of course each other.

"I like swimming in the sea," said Dyatchin. "It is better because the waves make it harder. I've been doing this for about eight years so I like it more difficult."

Even memories of crashing into a pod of blue blubbers at last year's Worlds in Melbourne have not put him off. They left horrific lacerations on either side of his chest, but did prevent him from winning the event.

"Yes, Australia has jellyfish," said the tough-as-nails Russian. "But, not a big problem for me."

"He is a great master of the mind," compatriot Denis Pankratov, gold medalist in both the 100m and 200m butterfly at the 1996 Atlanta Games, told China Daily from Seville. "He thinks only about 10km, and that's all. It's specialist. It's charisma. He is a man of one distance."

"When he heard that marathon swimming had made it to the Olympics, he came out of retirement and made two gold medals at the World Championships. Now we hope he will become Olympic champion," said Pankratov, now a sports commentator for Russian TV.

Dyatchin rates the two men he just beat in Spain, David Davies of Britain and Germany's Thomaz Lurz, as his biggest rivals. One year ago in Melbourne, defending champ Lurz was so close to the Russian that only 0.06 seconds separated them in a thrilling photo finish.

The reigning champ said he expects the Olympic competition to be a tougher nut to crack.

"I will need to acclimatize," he said. "There are more things to worry about. Same swimmers, but it's the Olympics. Everybody tries harder. This is the peak of our sporting careers."

It is also the reason he came out of retirement following an 18-month layoff spent studying engineering and mapping out a future working at his father's business in small-town Russia.

Yet, his experience, and his age, should hold the 25-year-old in good stead. So, too, should the fact that he won in Seville despite putting himself at 85 to 90 percent peak fitness.

"The marathon is not, I think, a young man's game," said Dyatchin, who also has a silver from the 2001 Worlds and a bronze medal from the shorter 5,000m event in 2003. "Thomas Lurz is now 28, for example. Older people have more power, and more experience of competitions."

Marathon swimming these days is attempting to cleanse itself of leg pulling, over swimming and other dirty tactics rather than the specter of performance-enhancing drugs.

"Yes, I think it has been (getting more aggressive)," said Dyatchin, who puts Vaseline on his ankles before racing to stop others from grabbing his legs. "But, no more because it is only 25 swimmers in the Olympics, compared to 55 for the World Championships."

He gets a two-week holiday after the Worlds. Then, it's on to training camps in Moscow, Cyprus and Slovakia. This means five or six hours hard work a day, including two days of running a week, three days of bodybuilding, and a swim session every morning and afternoon.

"Training very hard," he said. "But not hard for me."

A FINA-sanctioned Olympic qualifier for marathon swimming will be held at Beijing's Shunyi Olympic Rowing-Canoeing Park from May 31-June 1 as the final Good Luck Beijing test event.

At the Beijing Games, about 800 men and women will compete in 17 swimming events each from August 9-24, mostly at the National Aquatics Center. Marathon swimming will be staged at Shunyi from Aug. 20-21.

(China Daily 05/16/2008 page14)