During the summer, many Americans head for the beach or a pool to beat the heat. Others like their water white - tumbling down a river over rocks and around boulders. A summertime trip in a whitewater raft offers a sense of adventure that swimming in a pool or an ocean just can't match.

The serene sounds of a river can be misleading. Not too far from this placid part of the Youghiogheny River in the eastern state of Maryland, the sounds of the water change dramatically.

The Yok, as it is called, is one of the top whitewater rafting rivers in the country. When its water is high, part of the Yok becomes a run of rowdy rapids. Boulders jut out above the water's surface.

Just as the soft river flow can sooth one's soul, the rushing whitewater can raise an adventurous spirit. It's exciting, exhilarating and potentially dangerous.

"The river bottom here and on most rivers is just a huge series of boulders, all different sizes and shapes, making numerous little nooks an crannies," said Roger Zabel, owner of Precision Rafting and a veteran whitewater guide. "If you were out there trying to walk on the river bottom, you stand a very good chance of entrapping a foot or ankle between two of those rocks and then the current continues to push you over face first, where it becomes very hard to breath and hard for us to rescue you."

That was Roger Zabel's way of warning us to float on our backs, feet out of the water, if we fell out of the raft.

Recently, my fiancée Sharon and I joined about 20 other rafters on a three and a half-hour adventure down the level 5 rapids of the upper portion of the Yok. The Precision Rafting crew was there to guide us down the river. That was a good thing. Level 5 rapids are the most treacherous. The water crashes around and over the perilous rocks with no sympathy. For most of us, including teenager Christian Bowman, falling out of the raft was a frightening possibility.

"My biggest concern is definitely myself or someone in my boat falling out," he said. "I've heard so pretty scary stories of people getting trapped under rocks and stuff."

I was preparing for my first experience in a whitewater raft. Following the words of welcome and warning from Roger Zabel, groups of four, three passengers and a guide, clambered into about a half dozen rafts. Despite the assumed risk, I felt just a bit of apprehension.

The water was very calm during the first half-hour on the river, the quiet before the storm. That's when our guide, Oliver Grossman, briefed us about proper raft procedure.

"Try and keep it real simple, forward and back strokes, and I'll talk about what those are and how I want you to do them, it's pretty simple," he said. "Biggest thing is paying close attention. We'll be doing a lot of maneuvering once we get down into the rapids, the river's character is going to change."

The change was subtle. The serene setting of a calm river bordered by large clusters of trees was soon disrupted by the crashing sound of the onrushing rapids. We were the initial group through the first set of rapids, known as Gap Falls. And the water quickly claimed its first victim of the day.

That somebody was my sister, the fourth member of our raft. Judy lives near the Yok, and knows the rapids pretty well, so her fall took us by surprise. Oliver pulled her back into the raft within a few seconds. The only harm done was to her pride. In fact, no one was injured, although there were plenty of spills. One boy battled the water for about 15 seconds after falling out of the raft. He bobbed up and down between the rocks. For a few seconds, we lost sight of him. He surfaced about six meters down river, stunned, but unhurt. Christian Bowman who was so concerned about going overboard - was also one of the day's casualities.

"Felt great, I did fall in, my fear was realized, but it was still awesome," he said. "It was more of a rush going over the big rapids. It's definitely a thrill seeing all that power and energy in the water."

About half way down the river, some of the teenagers took time to reflect on the adventure as we drank from a string of fresh water dripping through rocks high up a steep hill from the riverbank.

"Yeah but I was under for like 15 seconds. And I was like, man, no way, I'm not going to die now, that's a scary feeling," one teen said.

"I know, because you went under, and a guy came from a kayak right where you were," said another.

About half a dozen solo kayakers rode down the river with us as safety guides. Each raft battled every one of the dozen or so rapids, one at a time. No one would leave until all the rafts had passed through a rapid successfully. When we reached land about four kilometers and three and a half hours after our adventure began, we all knew we had challenged ourselves, and won.

After conquering the mighty Yok, I felt invigorated, and comfortably fatigued. It felt good, good enough to someday try again.