Christian Nissen aka Hein Mück (1893 – after 1955) was a German sailor and yachtsman, who served with Nazi Germany's Abwehr and its special forces, the Brandenburgers in World War II.
Experienced yachtsmen trained by his special forces, the Brandenburgers, sailed the northern and southern Atlantic in World War II.
In June 1940 Nissen had been called to the Sabotage School at Brandenburg an der Havel to prepare for Operation Lobster I and asked to find a boat suitable for transporting three agents to Ireland.
Nissen's orders were to transport an NCO from the Brandenburgers, Helmut Clissmann, and one Abwehr I radio operator to the southern coast of Ireland to carry out their mission.
"Leutnant zur See" (or "Ensign"), Christian Nissen, also known as Hein Mück a traditional popular figure in Bremen, brought, together with Arndt Georg "Age" Nissen, Paul Temme and three other "Ghost sailors" (German: Geistersegler), the South African boxer Robey Leibbrandt with a confiscated French sailboat, Kyloe from St. Malo, France, down to South Africa and dropped him with a rubber dinghy at the coast northwest of Cape Town.