The Potomac began slapping at the raft from a dozen angles as soon as we whipped into the downstream flow.

The river was muddy, full from a week's rainfall and surging, as it does when the water is still rising. Angular currents rolled over one another, forming peaks and troughs that punched at the underside of the raft, tossing it in the air one minute, dropping it off the edge the next.

Our crew -- five customers and a guide -- cheered as we charged downriver toward the walled face of Rocky Island. I was loving it.

Now, that is an irony: a confirmed canoe paddler, with an inbred suspicion of rafts, luxuriating in the comfort and safety of one -- a river rat turned hedonist.

"Right. Now!" yelled the guide as we closed on Rocky Island. We paddled hard on the left side and the right reversed or braked and slowly the raft changed headings and slid around the island into Mather Gorge.

The Gorge compresses all the river's energy into a narrow, steep-sided channel. At the water level that day, whirlpools boiled along the edges. At lower water levels they disappear, the current slows down and the rafts will be able to tarry and explore the geological formations exposed in the rocks.

There was low water in the Gorge last fall, when my friends and I first saw the rafts from Potomac River Tours. I had been in a canoe then.

Two reactions hit me almost simultaneously: delight that more people could safely see the geological fantasyland in Mather Gorge and dread that the Potomac might someday be like the Youghiogheny, where rafts can be so thick you could step from one to another.

Rafts, canoes and kayaks share many rivers and often help one another, but it's an uneasy alliance. It's unnerving, after all, to find a bulky raft bearing down on you when you're in a canoe stuck in a hydraulic. It's probably just as unnerving for the rafters, but they're bigger.

Thanks to National Park Service policy, the Potomac below Great Falls had largely been the province of canoes and kayaks. We played in its feisty waters and renewed our spirit in its isolation and gradually came to consider it ours.

It would be a while before I realized that we had encountered, on a personal level, what may become the national dilemma of this half of the century -- use versus preservation. That would come much later, after hours of talking with boaters, rafters, the National Park Service and Bob Marshall, the Washington native who owns Potomac River Tours (PRT).

Bob Marshall is a river rat himself -- a kayaker -- with a deep and evident love for the river and a desire to share it with others. He began taking friends on raft trips in 1976. As more people asked to go along, he started thinking about a commercial raft service.

"I really enjoyed seeing people have fun," he explained. "I liked giving them an opportunity to explore nature on her terms, and -- "he paused -- "I just like being out there."

He started Potomac River Tours (PRT) as a part-time business in late 1980, getting permission from the park Service to launch from the Maryland shore. Later, he also got a license to use the Virginia shore, which lets him start the trip at the base of Great Falls.

The Park Service does not control the river below Great Falls, but it controls the land on both sides and, so, access to the river. It has strictly limited boat access because the river there is dangerous, and the policy has paid off with an excellent boat-safety record.

When the Park Service decided to grant Bob's application to use the Virginia park, it was because -- as river safety officer Bill Kirby put it -- "We felt it encumbent on us to provide an opportunity" for the public to enjoy "what is really the outstanding outdoor experience in the Washington area."

The license granted to PRT, which must be renewed each year, carries restrictions to assure safety, protect the historic sites in the park and the rights of other park users, and provide "a quality experience." Among the rules are minimum standards for rafts, life jackets and the other equipment.

So far, Kirby said, PRT's performance has been letter-perfect.

Just before the six rafts on our trip -- four with guides and two without -- started downriver, Bob gave a lecture on safety, and it set nerves tingling through the crowd.

Most of the trip is a scenic float, as described in the PRT brochure, but it begins with whitewater; and because of the water level that day -- 4 1/2 feet -- it was especially rambunctious.

Joan, Denise, Regis and Tom shared a raft with me and guide Gary Ratcliff. They were grand companions, cheerful and ventursome. Most of them had never been on a raft trip.

The biggest waves on the trip were waiting for us at the end of Rocky Island. The lead raft hit them just as one surged and exploded in foam-studded spray, tossing one rafter overboard. He was picked up right away.

We climbed the first wave and then dropped suddenly, like a plane hitting an air pocket. Water washed over us as we stumbled into the second, bigger wave, lurched upward and then hung, suspended, before diving wildly into the trough. No mechanical bull could match our rubberized Brahmin.

Before we could climb off our knees and get our heads centered again over our shoulders, we slid over the ledge at Wet Bottom chute, and began slowing down, our adrenalin still pumping in waves.

At first no one said anything.

Then someone, maybe everyone, sighed.

"Are there any more like that?" Joan asked, hopefully.

"Not really," Gary replied, "but now you can see the Gorge. We were flying too fast before to even point out where the Potowmack Canal began." He pointed out chunks of quartz, fault lines, river-sculptured rock and the remnants of the canal. We spotted a single pink flower clinging to a minuscule ledge of rock 20 feet above our heads, but couldn't identify it.

The crew showed the same excitement and awe others have felt in the gorge, and Gary had an appreciative audience.

Just above Difficult Run, where Mather Gorge ends, Bob waved all the rafts to a stop, "so the boaters playing in the rapids ahead will know how many of us there are and when we've all gone by," he explained.

Below Difficult Run, the Potomac gets very much wider and is divided in places by islands and punctuated by three rapids, small compared to the one at the beginning, and shorter. Those rapids, with names like Offut, Yellow Falls and Stubblefield, can be technical and sometimes breathtaking in a canoe, but they seem mild in a raft compared to the bodacious stuff already run.

The islands and shore were thick and deep green with rain-fed vegetation that screened out the world. We could have been anywhere except 10 miles from downtown. The only break in our solitude was the occasional plop of carp. We did pass a group of canoeists.

We had seen few birds, which was curious since osprey, Great Blue Heron, gulls and nations of crows inhabit the area. Maybe they'd taken a week in Arizona to dry out from all the rain.

We stopped for lunch at Scott Falls in Dranesville Park. Usually, the falls is cold and clear and makes a natural air-conditioner. That day, like the river, it was running brown and full of sediment.

Most of the rafters postponed eating to try the rope swing over the river, or to watch somebody else try it. "Jump," the crowd yelled to hurry along any recalcitrants.

"Let go," they'd prompt when the rope reached its full arc over the deepest water.

When we packed to leave, I noticed Scott Falls was cleaner than when we'd arrived. Marshall and the guides had done a quiet litter pickup.

The last rapid is about a quarter of a mile below Scott Falls, and our crew decided to float it sideways. I thought of the times I'd wanted to do that in my canoe, but hadn't the nerve. Then, I'd done a lot of things that day I couldn't have done in the canoe, like seeing the river inside the Gorge at 4 1/2 feet.

Joan and Regis liked the whitewater and asked Gary about taking kayak lessons. Gary said later a lot of people are interested in learning more about canoeing and kayaking after rafting the river. He had started kayaking because of a raft trip. It reminded me that I started canoeing after a raft trip, in 1973 in Wyoming.

Gary went on to say that most of the rafters are from Washington, but have not really seen the river before, and they're just amazed. They get really exicted. He sees the raft trips as a way to sensitize people so "they will understand what it is we could lose."

However, he shared the fear all knowledgeable boaters have, that people will go out on the river on their own without the skill or knowledge to handle it, a point accentuated by the recent spate of drownings.

Civilization intruded again at the Cabin John bridge, where some secret spirit lives that infects all river-runners with silliness. We finished the trip with water fights, bumper rafts and spin-the-rafts-in-a-barrel, which launched a few folks into the river. When we reached Lock 10, still wet and laughing, I was sorry to see the trip end.I knew I would recommend it to others, especially non-paddling friends who had heard me talk so much about Mather Gorge.

The dilemma stays with me, though I have come to some reassuring conclusions:

First, the PRT Tours are professionally run with a high standard of safety and environmental concern.

The trip is a good rafting sampler with some short bursts of whitewater interspersed with peaceful floats through semi-wilderness, giving a lot of people a chance to enjoy the beauties of a free-flowing river.

The Potomac is not likely ever to be another Youghiogheny -- it doesn't have the miles of heavy whitewater that attracts thrill-seekers and it does have the Park Service as a guardian.

For now, the Park Service seems to have struck a rational balance between protecting the river and letting the public use it on a restricted basis.

As for the future, in the long run, it tends to be what people want it to be. The challenge for those of us who want it to be balanced may be, as Gary Ratcliff put it, to help people "understand what it is we could lose."

One way to do that is to provide an opportunity to enjoy "what is really the outstanding outdoor experience in the Washington area."