THE NEXT MORNING, at Lewis Meadow, we prepare for our two-day float to sea. I inflate my life vest, and Roo improvises a second one by stuffing my sleeping pad inside his drysuit top. The Michelin Man and I don ball caps for helmets and eddy out into the glacier milk flowing by in large, deceptively inviting riffles. We pass herds of elk and all sorts of birds in the wide, wild valley. Warm sun sifts through maple trees draped in witch's hair moss.

If there were an award for high-performance butt-boats, the Alpackas would take top honors. They spin and ferry like champs, and by the morning of our second day on the water, we're ducking river-wide limbo bars, scraping over half-submerged logs, and tempting huge root balls that look like entrances to other dimensions. It's serious combat-boating, and we capsize and lose packs overboard, but otherwise navigate the Idiot Sieve in good style.

Ever vigilant, Roo warns me to keep an eye out for a horizon line near the ocean. "It's the top of a 500-foot waterfall."

"Sorry, Roo," I reply. "According to the map, there's no way we have 500 vertical feet before the ocean."

"That's what makes the falls so dangerous," he says, continuing the ruse.

An hour later, the air has grown softer and a notch in the forest opens onto an expanse of blue. Paddles wheeling like that of a Mississippi steamer, we race through a tidal estuary to the windswept sand beach of the Pacific Ocean, at the Hoh Indian Reservation.

We holler and high-five and strike gallant poses atop gnarled driftwood logs. I can't help but reflect on the Navy diver's comment. To wit: Who's stupid now?! I'm about to share my deep insight with Roo when we see a gray Suzuki SUV bouncing down the beach toward us. It's our ride home—the heroes' dads, with ham sandwiches.