AT SEA.(The Talk of the Town)(Current Taxi, river boat service)

In theory, the Tide and Current Taxi was supposed to work like this: You'd call Marie Lorenz, the volunteer dispatch officer, ship's pilot, and all-around free spirit, and tell her where you wanted to go--not right away, because tides and currents aren't immediately obliging, but at some point in the near future. Lorenz would study the weather forecast and the tide charts, and then suggest a meeting place and time that fit her schedule and, ideally, didn't much conflict with yours. If you were an Upper East Sider commuting to Wall Street, you might like to meet her at the crumbling dock at Ninety-first Street on the East River, to catch the outgoing tide at 5:15 a.m. You'd climb aboard her homemade fourteen-foot plywood skiff--Lorenz is a sculptor--and float slowly down to South Street Seaport, paddling when necessary to insure that you made it on time for your eight-thirty conference call.

In practice, there were some complications. For instance, a great many large motorboats--barges, tugs, Circle Lines, pleasure cruisers--navigate the East River regularly, leaving perilous wakes for a small, flat-bottomed craft to negotiate, and generally making an east-to-west crossing resemble a game of Frogger. Also, there are surprisingly few places to dock, particularly on the Manhattan side. On Lorenz's maiden voyage, the boat was swamped by waves rebounding off the seawall at East Thirty-seventh Street, and eventually sank, leaving Lorenz and her fare to swim ashore at Roosevelt Island.

After rescuing the submerged boat, Lorenz made some repairs, adding several inches of coaming around the perimeter for extra wave protection, and replacing the Styrofoam coffee cup that she'd been using as a bailer with a proper milk jug. She also amended her terms of service: there would be no more Manhattan landings. Passengers would have to accept that they might end up nowhere near their specified destinations, if they launched or landed at all.

Midway through Lorenz's weeklong trial run, last month, a man with no particular place to go ...