One of the reasons I enjoy swimming is the exquisite embrace of total immersion. That’s why I don’t wear a wetsuit. That’s also why step one in my Alcatraz quest was simply seeing if I could endure the notoriously cold water of San Francisco Bay. In 2006, when I was back in the Bay Area, a new friend, Kate, invited me to join her at Aquatic Park, a public swimming area on the San Francisco waterfront. On an overcast fall morning, I went for my inaugural swim, wearing only a Speedo and a cap.

Public pools are typically kept between 80 and 85 degrees, while lap pools range from 75 to 80. The water here was 57 degrees, with patches even chillier. Had I lingered a few seconds where the water was shin-deep, my ankles would have gone numb. So I kept walking. The cold advanced up my legs, over my knees, convincing me that an all-at-once shock would be better than prolonging my entry any longer. I dove headfirst. My chest tightened, my temples ached, I gasped for breath. It seemed as if my entire body was about to shut down. Then raw instinct took over. I swam a couple of strokes, reversed direction, swam back, left the water, and ran back in, repeating the process several times until the cold lost some of its sting. When I was ready, I turned to my much more experienced partner: “Okay, Kate. Let’s go.” We plunged in together. And this time I kept going.

Remember this day, I said to myself. Hold on to it. I was cold, yes, but also electrically alive. We swam parallel to shore, and after a few minutes I passed over the threshold that all sea swimmers come to know, and trust, when the warmth one generates internally becomes the equal of the surrounding water, or so it seems, and seeming so is enough.

As Kate and I warmed up in the saunas at the Dolphin Club, which shares a building with the South End Rowing Club at Aquatic Park, I could scarcely contain my joy. It was as if I’d discovered a new country, one I was eager to explore. With my skin still tingling, I decided: I would attempt a crossing. I was 56 years old, in fairly good condition, though surely no gonzo athlete, and surely not without doubt. But I had to try it. I would make the attempt during the next Alcatraz Invitational, a swimming event that South End holds every year in the raw, dark waters of San Francisco Bay.

During the two weeks before I returned to Montana, I continued to swim at Aquatic Park. And during each workout, I paused in the outlet separating the relatively calm lagoon from aqua incognita beyond. There, alone in the water, I gazed at Alcatraz. The crossing would be 1.25 to 1.5 miles, depending on the currents, but the island and its notorious federal penitentiary seemed much farther away. I shuddered, then worked my arms and legs faster to fight off the encroaching chill. It was easy to imagine being paralyzed and disoriented by the icy water and daunting currents. The inmates were told that the bay swarms with man-eating sharks, a lie that discouraged everyone but the most daring from attempting escape. The cold and the danger occupied my thoughts as I studied Alcatraz. *How strong will the currents be on the day of the race? What about the chop? Will I be tossed about like a cork? Okay, the sharks are harmless bottom feeders, but who really knows what will be eyeing me from below?*

Even without the lore, Alcatraz remains forbidding, by virtue of its physical presence alone—a cluster of brooding buildings anchored to a platform of solid rock. Sometimes enshrouded in fog, other times lit up by the sun, the island shifts mood from hour to hour. It can look like a majestic ship plowing across the bay, a castle floating eerily above the water, or a deserted, ominous outpost of wrecked ambition.

The feeling in the tips of my fingers was ebbing away, telling me that I needed to resume swimming. I turned away from Alcatraz and swam back toward shore, arm over arm, pulling harder as I went, now more appreciative than ever of the challenge that would await me upon my return, a year later, on September 15, 2007.