The first clue Curt Gordon had that something was wrong was a twinge in his calf muscle.

Splashing into Kona, Hawaii on Oct. 19 against a swelling tide at the end of the 2.4-mile swim that was the first leg of the Ironman triathlon world championship two weeks ago, the 45-year-old Gordon, a Clinton resident and first-time Kona competitor, was suddenly a little unsure about what he was doing. A veteran of two Ironman-distance races in other locales, he knew from experience that he could finish the swim, a 113-mile bike ride and a 26.4-mile run.

But the cramp in his leg so early in the race was something new.

Though he would go on to finish Ironman Kona — perhaps the most feared ultra-endurance athletic event in the world — Gordon was learning from the start that no one conquers this race: Kona and the island of Hawaii dictate who is fast, who is slow and, often, who is allowed to finish.

But as Gordon exited the water into a 75-degree drizzle behind the 1,200 other people who outswam him, a couple dozen of his fans, watching from the shore and over the Internet from Whidbey Island, knew he would make it.

“I knew he’d finish,” said Gordon’s friend and former high school cross country coach Carl Westling.

Westling and his wife, Pat — along with Gordon’s three daughters, his wife, mother and friend Dean Hatt — journeyed to the Big Island to watch the race and to see Gordon meet with a destiny set in motion 17 years ago.

In 1985, Gordon, joined by Westling, did his first triathlon. That race was short, with the total mileage being no greater than the Ironman run. Ironman was only an unattainable fantasy.

Two Saturdays ago, that was no longer the case. Though hampered by recurring cramps brought on by dehydration from a case of the flu two days earlier, Gordon pushed through downpours, coastal winds, and a bicycle collision with a large German cyclist to become South Whidbey’s first Ironman Kona finisher.

Back on Whidbey Island this week, Gordon said Kona was more “brutal” than the two qualifier Ironman races he did in Canada over the past three years. Finishing 820th out of 1,492 finishers in 11 hours 32 minutes, he was more than an hour slower in finishing than at Ironman Canada two months ago. Even so, his finish place ranked him ahead of all the 45-49 year olds he beat in Canada.

“And I felt like I was having a bad day,” he said.

A bad day, especially one that would force him to drop out of the race, was not acceptable. Three years ago, Gordon promised his wife, Susie, and his three daughters and their families that he would fly them to Hawaii at his expense if he qualified for the race. When he did that this summer, that is is exactly what happened.

Adding to the pressure to complete the race brought on by having family at the finish line was having over a dozen training buddies at home rooting for him for much of the day. His Ironman training partner, Brandon Henry, said he had to call Gordon a few times to keep his mind on the race. He reminded him that he had earned his shot at Kona.

“He was very definitely having a crisis of confidence,” he said.

Marti Reiss, another triathlete who trained with Gordon this year, was one of many of his friends glued to her computer waiting for live updates on the race’s Web site. She said watching on the monitor helped her feel like she was there to cheer on the one island athlete who had achieved her sport’s loftiest goal.

“Watching him was living vicariously,” she said. “It’s inspiring.”

Even those of his fans who don’t compete in the sport could see the effort it took as Gordon rode into Kona after the swim and bike to start his marathon-distance run. Dean Hatt, a former South Whidbey runner himself, said he was awed by the accomplishment.

“To train for an event like this and finish is incredible,” he said.

Only the competitor was hard on himself. After the swim and bike ride, he ran the first half of his marathon a about 8-minute per mile pace. Cramps later slowed him, but eventually, after taking several salt pills and drinking water, he was able to finish at a slower pace.

The run took so long, he came in after dark, something he did not want to do. So he ignored Hawaii’s early nightfall and refused to take one of the glow sticks handed out by race officials to light the way.

“I guess I would not accept that I would finish after dark,” he said.

After it was all over, though, there was no disappointment. Susie Gordon said she enjoyed going along for the ride, even though that ride required her husband to spend almost every free moment he had over the past year training. She said she was just happy to see him cross the finish line looking better than he did at his first Ironman race in 2000.

And though it was part of the couple’s deal for Gordon to back off training and perhaps not try for Kona again until he turns 50, Susie Gordon said she figures she will be back on the Big Island again sometime soon.

“You know what, I think he’ll do it again,” she said.