Hamburg is not on the coast. Why is shipping so developed?

Although Hamburg, Germany is not a typical coastal city, the famous Elbe River in Germany flows through Hamburg. It can be said that the mouth of the Elbe River is Hamburg, which flows into the North Sea through the Elbe River in Hamburg. The Elbe River is long and flows through many developed cities. The river runoff is stable all the year round and the shipping value is high, which leads to a very developed shipping industry in Hamburg.