All dedicated athletes have obstacles to overcome while training.

But not many have to deal with a bike ride that could be interrupted by a large wave or having the swim portion of a half-triathlon in a pool because there are sharks in the lagoon.

Such are the challenges that have faced Jeremy Pederson, a chief gunner’s mate in the U.S. Navy, and serious triathlete. Much of his training has been done aboard ship, most recently the Pearl Harbor-based frigate USS Crommelin.

"Training is always an adventure when you’re deployed," said Pederson, who is entered in his third Bikefactory North Shore Triathlon on Saturday. "My wife (Thinzar) got me a bike trainer that plugs into my laptop. I can sit and pedal all these (virtual) courses. The training simulates hills by putting pressure on the back tire.

"A frigate is a small ship. We rock too much to lift weights. And trying to run on a treadmill is like you’re running (snow) moguls. The guys would see the cord coming out of my computer and ask, ‘Where are you going today?’ "

One day, the answer would be France. Another day, it would be Germany. All while the Crommelin was somewhere in the Pacific Ocean.

In four-plus months, Pederson toured most of Europe virtually and pedaled 1,000 very real miles.

The 36-year-old was a swimmer growing up in Wisconsin. He didn’t get into endurance sports until entering a mini-triathlon while on Diego Garcia, a small atoll in the Indian Ocean.

"That was kind of funky," he said. "We couldn’t swim in the ocean or lagoon because of the sharks, so we did 300 meters in the pool. The bike ride was like 12 miles and it was a 5K run. It was a lot of going in circles."

Getting orders to Hawaii changed everything. He did his first Olympic-distance triathlon in 2007 and "that was pretty big for me," Pederson said.

In other words, he was hooked.

"But the bad thing about sea duty is … you’re at sea," Pederson said. "We were deployed for the entire triathlon season in ’09. In 2010, I was gone for most of it. I think I raced 25 events in 2008 and just one the next two years. It was a 5K when we were in port in Singapore. We weren’t in shape, but at least it was a run."

Pederson hasn’t met a race he didn’t want to enter. Days after completing the 2008 Ironman Western Australia, he was back in Hawaii … just in time to enter the Honolulu Marathon. He finished his first 26.2-mile race in 4 hours, 15 minutes.

His goal is the Ironman World Championships in Kailua-Kona. Pederson hasn’t qualified through the lottery yet and his time at the June 13 Honu Triathlon on the Big Island — which is a half-Ironman — wasn’t good enough to qualify.

"I want to suffer with everyone else on Queen K," Pederson said of Queen Kaahumanu Highway, part of the Ironman marathon and bike courses.

It likely will happen, given that Pederson’s final military tour is a short one not far from his home in Aiea. And, following that three-year tour, he plans to retire here after 20 years in the Navy.

"I’m looking forward to being home and actually being able to train consistently," he said.