She needed to get out. Wide of beam, 43 feet long, and 11,000 pounds of lead in her keel, she'd been built with oceans in mind. Her name was Dolphin's Waltz, and she was sick of putzing around the shallows of Alabama's Mobile Bay, where she docked. Now, stately breakers rolled across her bow, muddy waters giving way to the gray-green Gulf of Mexico. She was on the hunt.

We passed within kissing distance of shrieking rigs, hunkered down and drilling away like mosquitoes; dodged a swarm of shrimping boats that looked like giant waterborne grasshoppers, their spars deployed as they searched for oil slicks; and then made for Dauphin Island Pass and the wide open. A Coast Guard chopper slashed overhead, and a blimp hung in the southern sky like an alternate moon. We were the only pleasure boat around. A west wind snapped the jib taut as dolphins hot-dogged across our bow wave, exploding into the air. For being smack in the middle of America's biggest environmental disaster, it was pretty fucking nice.

You might say July 2010 was an odd time for a pleasure cruise in the Gulf of Mexico, and maybe a sailboat—slow, bulky, with the upwind quarter of the world off-limits—is an odd way to do any sort of journalism. I won't argue. I wasn't going to scoop The Wall Street Journal, but that was the point. Perhaps, as the press hordes stampeded past us in their helicopters and vans, chasing the latest oil sighting, they were missing the real story.

So we'd take it slow, on the gulf's schedule. I'd challenged our skipper, Josh Deupree, to a wind-powered tour of a particularly stunning corner. I'd heard rumors of cleanup operations gone awry—workers pelting each other with eggs from Louisiana rookeries—so we'd head west to investigate the situation on Petit Bois Island, known as the most pristine wilderness island in the gulf and vital habitat for more than 250 species of birds. From Petit Bois we'd cross Mississippi Sound to see the marshes and seagrass meadows of the coast, taking in as many marine ecosystems as we could in three days.

A sort of nagging consumer guilt, and the desire for seafaring in its purest form, was the motivation to try it without fossil fuels—once out in the gulf, at least. Sailboats are docked in slips like parking spaces. Exiting had involved cranking up, making several right-angle turns, negotiating a narrow harbor, passing under a bridge, then following a dredged shipping channel across Mobile Bay and out into the gulf.

As soon as we'd cleared the bridge and caught the shipping channel, we killed the engine and raised the sails. Close-hauled to the wind, Dolphin's Waltz heeled over and shot straight out of the channel toward Dauphin Island Pass. The smell of diesel faded, replaced by the slow oscillation of wind and wave. She was free.

Not that we were making any kind of statement. Just getting to the boat, our crew had of course burned gobs of petroleum products. I flew from Vermont to Newark, where I looked down upon a grid of refineries and tanks, then to Houston, same damn thing, and then to Mobile. Oil was everywhere and in everything, not just the gulf.

LIKE SOMETHING OUT OF MORDOR, a refinery's orange methane flare blazed atop a black pillar on the shore of the bay. Fed by six rivers, Mobile Bay covers 413 square miles and spits out some 62,000 cubic feet of water every second, making it North America's fourth-largest estuary by flow. Its mouth was crawling with boats as we sailed out. Vessels of Opportunity—boats hired by BP to patrol for oil—darted across the channel. The program was the biggest gold rush on the coast. Even the smallest boats made $1,600 per day.