J.W. Westcott delivers mail to moving Great Lakes freighters by tugboat and bucket

In an NPR report (2016), Quinn Klinefelter of WDET rode with the J.W. Westcott Co., which has delivered mail and supplies by boat on the Detroit River since 1874. Freighters carrying coal or iron ore pass along one of the few shipping lanes there and slow only to a certain point, as Relief Captain Neil Schultheiss says: nowhere else are you alongside a ship of this size at these speeds.

The company began with a rowboat and now uses a tug, according to NPR the only one with its own ZIP code and, per a later clarification, the only U.S. boat that is a full-time post office. The operations center radios each freighter, then Captain Sam Buchanan steers toward it. Big tires line the tug, which brushes the hull of the ship, towering about five stories above the water. The crew lowers a bucket to the tug, which Buchanan's crew calls 'mail by the pail', and he salutes with his whistle.

Buchanan says he takes almost anything out to the freighters: packages, replacement sailors, even once a goat. The company makes two or three dozen deliveries a day between April and December. The mail boat was built in 1949 and sank to the bottom of the river in 2001; the crew chose to put it back together, and Buchanan predicts it will survive as long as ships sail the Lakes.

Freighters will not stop for the mail, so the service has to match their speed instead.

A bucket on a line needs no dock, no crane and no stop, so the hand-off works with equipment every ship already has.

Tires on the tug make a gentle 'controlled collision' with a hull five stories high a routine procedure.

Because sailors now order online, parcels still need physical delivery, which keeps demand alive.

If the customer can't leave their route, bring the service to the route. A cheap, repeatable hand-off beats redesigning the schedule.

The tug was raised after sinking in 2001 and was still in service at the time of the 2016 report, making two or three dozen deliveries a day between April and December. NPR later clarified that Point Baker, Alaska, has a post office on pontoons by a dock, but with limited hours; Westcott is the only full-time post office boat.