Commander of the Order of Orange-Nassau Expedition Cross with clasp for Timor 1942 War Commemorative Cross 1940-1945 Decoration for Order and Peace Legion of Merit Willem Jan Kruys (1906–1985) was a vice admiral in the Royal Netherlands Navy and later director-general of the Dutch National Aviation Authority (Dutch: Rijksluchtvaartdienst).

From 1935 to 1938, Willem Jan was artillery officer aboard HNLMS Johan Maurits van Nassau, first stationed at the island of Curaçao in the Dutch Caribbean, and later escorting convoys in the Strait of Gibraltar.

On 6 May 1942 he became captain of HNLMS Tjerk Hiddes, a British N-class destroyer launched on 25 June 1941 and transferred to the Royal Netherlands Navy in May 1942.

[6][7] With HNLMS Tjerk Hiddes, Willem Jan actively participated in the fight against the enemy, initially escorting military convoy ships in the Indian Ocean.

In September, the ship joined allied forces allocated to support landings in the Battle of Madagascar against the Vichy France government.

Several evacuation attempts had failed after HMAS Voyager ran aground at Betano Bay and was damaged beyond repair by Japanese bombers.

[9] On 9, 12 and 18 December 1942, the Tjerk Hiddes made three nightly voyages to Timor and evacuated over a thousand Australian Forces, Dutch troops and civilians to Darwin.

The troops were recalled from Egypt by Australian Prime Minister John Curtin, in response to the Japanese threat to Australia.

King George VI of the United Kingdom decorated Willem Jan with the Order of the British Empire (Officer Military Decision).

[15] On 18 November 1953 Willem Jan became the first captain of the new cruiser HNLMS De Ruyter, built at the Wilton-Fijenoord shipyard in Rotterdam.

[16] In his speech at the ceremony Willem Jan said:[17] "We now have the privilege of serving again on board a new cruiser, which has been named De Ruyter by Your Majesty.

(...) we will give our best efforts to this beautiful new ship, guided by one inspiring thought to make it, with God's blessing, the pride of your fleet.

Nevertheless, Cornelis Staf, Minister of War, was of the opinion that the comments were regrettable because they could be interpreted as a judgement of the government's policy, even though they were not intended as such.

[22][23] His Royal Netherlands Navy uniform (pattern 1959), including cap and vice admiral's monkey jacket, is part of the collection of the National Maritime Museum in Greenwich, London.

[24][25] Willem Jan retired from the Royal Netherlands Navy on 16 September 1960 and became deputy director-general of the National Aviation Authority (Dutch: Rijksluchtvaartdienst).

He contributed to the joint NATO project Atlantic anti-submarine aircraft and the Satco automated air traffic control system.