The Oberleutnant zur See usually needed 3 to 4 years to be promoted to this rank, but is was also possible to reach this rank in 2 years, depending on position and obtained successes.

The Kapitänleutnant wear the plain shoulder-strap with two stars, the Kapitänleutnant (Ing.) had a cog-wheel on the shoulder-strap (see left).

They had one stripe on the shade of cap. On the arm they wear two broad strips, in the middle one narrow and over it the star (engineer officers also wore the cog-wheel).

Usual abbreviations were 'Kaleunt' or 'Kaleu'.

Kapitänleutnant Günther Prien	Kptlt. Otto Kretschmer after patrol
Kptlt. Helmut Rosenbaum Commander of U-73	Kptlt. Herbert Sohler Commander of the 7th Flotilla