Before the Japanese invasion of the Dutch East Indies, he was the flag officer in command of the important naval base at Soerabaja.

He realised the invasion of Java was just a matter of time, and started to prepare the evacuation of naval personnel to Ceylon or Australia.

From 6 October 1945 to 21 January 1946, Koenraad continued his task as the Acting Commander of the Navy in the Dutch East Indies, with its headquarters in Batavia.

[4][5] Although Koenraad was not a particularly powerful military figure, in March 1942, during the evacuation of the navy from the Dutch East Indies, he acted independently and responsively, so that he and his naval staff were able to evade capture by the Japanese.

The lack of communication with the Commander of the Dutch East Indies Armed Forces, Vice-admiral Helfrich in Colombo (Ceylon) did not facilitate his task.