It's wretched weather for putting out to sea: gusty winds, cloud banks brooding with rain and water spouts, temperatures a micro-notch above freezing and the waters of Tokyo Bay like wet elephant hide. Nonetheless, at the generous invitation of the Tokyo Metropolitan Government's Bureau of Port and Harbor, I've come to the Takeshiba Terminal to enjoy a free "minicruise" of the Port of Tokyo on board a 31-meter vessel, the Shin Tokyo Maru. As I slip over the ship's gangplank, I can't help but hum the theme song to "Gilligan's Island," the iconic TV sitcom that all began with the fateful trip of the tiny ship S.S. Minnow.

Luckily, the Shin Tokyo Maru is no such small fry. The gleaming white three-deck cruiser is immaculate, given that it was first launched in 1983, and, inside at least, appears set to receive the executive board of the United Nations. A vast conference table dominates the first deck, surrounded by 30 office chairs in lace antimacassars. The second deck, too, is appointed like a formal living room, with standing lamps, coffee tables and a box chandelier that tinkles with each shift of the boat's hull. Only the faint odor of marine fuel in the air and the revving of engines clue me in that the voyage has begun.

Pausing to admire photos of Emperor Akihito and Empress Michiko, who toured on board back in 1983, I head up to the third deck. Special members of the media are allowed up here, where the captain and his engineers work throttles to ease the craft from its dock. It seems unwise to crowd the crew, however, so I head to a door at the rear of the control deck, which leads outdoors.