The Hanseatic city of Bremen at the mouth of the River Weser was one of Europe’s principal ports for many centuries, but its harbour could not accommodate vessels that drew more than 2 m, and in 1827 a treaty with Hanover provided for a 25 ha site down river to be developed as a port for transatlantic shipping that came to be called Bremerhaven. The Alte Hafen (old harbour) was completed in 1830, the Neue Hafen (new harbour) in 1847-51, and the Kaiserhafen (imperial harbours) were laid out between 1872 and 1909. The Kaiserschleuse of 1897 and the Norschleuse of 1931, two of the world’s largest sea locks, keep the harbours independent of tidal flow.
The maritime museum was established in 1972-75. Its collection includes four vessels that conserved on shore, including the only remaining Hanseatic cog, and ten which are moored in the old harbour, including the sailing barque Seute Deern (built in the United States in 1919 as the Elizabeth Bandi), he Greenland, a polar exploration ship of 1867, a fireboat, the Kossel Paul which has a concrete hull, a fireboat and several tugs. There are several cranes, the earliest worked by steam, the latest a portalhubstapler, built for handling containers in 1968. The museum has over 500 models and indoor displays that are focussed on the German merchant fleet of the 1920s and 30s, the role of Bremerhaven in emigration to the Americas, polar exploration, whaling and fishing and boat-building. There is a well-equipped wet wood laboratory for conserving ships and artefacts.