Alan, there was indeed a vessel called "Horst Wessel" after the SA man.

"Horst Wessel" was build 1936 at Blohm & Voss in Hamburg as a school ship. There were a number of sister ships, including the present Bundeswehr sailing schoolship "Gorch Fock II". "Horst Wessel" was claimed by the USA after WW2 and now serves the Coast Guard for cadet training, renamed "Eagle".