Nauticurso JW Westcott II 1:35

JW Westcott II is a boat known for delivery of its mail to ships while they are underway. It operates out of Detroit, Michigan, and is the only floating zip code in the United States. 

The Westcott company was established in 1874 by Captain John Ward Westcott, who ferried supplies (and by 1895 the mail) to passing ships via rowboat. By 1949, the company commissioned Paasch Marine Service of Erie, Pennsylvania to build J.W. Westcott II, named in honor of the Westcott company's founder. The ship is 45 feet (14 m) in length and has a beam of 13 feet (4.0 m). A single screw is powered by a 305 horsepower (227 kW) marine diesel engine. The boat's speed is rated at 15 knots. 

Any mail addressed to members of ships' crews on vessels transiting the Detroit River can be delivered to them via J. W. Westcott II by being addressed "Vessel Name, Marine Post Office, Detroit, Michigan, 48222." The US postal zip code 48222 is exclusive to the floating post office and its ship addressees; as of 2016, the boat has a contract with the US Postal Service through 2021. The mail is delivered to the appropriate ships (mainly lake freighters) as they transit the Detroit River, utilizing ropes and buckets. 

On 23 October 2001, J. W. Westcott II sank in the deep water under the Ambassador Bridge while caught in the wake of Norwegian oil tanker MT Sidsel Knutsen. The captain and one other crew member were killed; the two passengers, both pilots, were rescued. J. W. Westcott II was later salvaged, refurbished and returned to service.