Well, I’ve been on the North Sea from Norway and sailed from the huge German seaport of Bremerhaven to the USA and back a couple of times.
Landlocked is landlocked. Germany is far from landlocked.
Their access to the Atlantic proper (from two separate routes) made the German navy a huge factor in WWII.
I had other issues with the article.
The German Navy wasn’t much of a threat after 1941. Not the surface navy anyway. Hitler admitted to being a ‘’coward’’ at sea. The German U-boat fleet was another matter. U-boats almost point Britain to the point of starvation.