The Kapitänleutnant had to serve an average of 5 years or longer before being promoted to Korvettenkapitän (Dönitz needed almost 8 years in the twenties). During the war this time also became shorter.

In 1942 'Teddy' Suhren got his promotion after only 8 months!

The Korvettenkapitän wear the plain braid shoulder-strap (see left), the Korvettenkapitän (Ing.) has a cog-wheel on the shoulder-strap.

They had a broader stripe on the shade of cap. On the arm they wear three broad stripes and the star (engineer officers also wore the cog-wheel).

Korvkptn. Karl-Friedrich Merten
Commander of U-68.