HNLMS Kortenaer (Dutch: Hr.Ms. Kortenaer) was an Admiralen-class destroyer of the Royal Netherlands Navy, named after 17th century Dutch Admiral Egbert Bartholomeusz Kortenaer.

In the mid-1920s, the Netherlands placed orders for four new destroyers to be deployed to the East Indies. They were built in Dutch shipyards to a design by the British Yarrow Shipbuilders, which was based on the destroyer HMS Ambuscade, which Yarrow had designed and built for the British Royal Navy.

The ship's main gun armament was four 12 centimetres (4.7 in) guns built by the Swedish company Bofors, mounted two forward and two aft, with two 75 mm (3.0 in) anti-aircraft guns mounted amidships. Four 12.7 mm machine guns provided close-in anti-aircraft defence. The ship's torpedo armament comprised six 533 mm (21.0 in) torpedo tubes in two triple mounts, while 24 mines could also be carried. To aid search operations, the ship carried a Fokker C.VII-W floatplane on a platform over the aft torpedo tubes, which was lowered to the sea by a crane for flight operations.

Being a destroyer, Kortenaer was unarmored, and she was capable of 36 knots, and could traverse 5,900 km (3,666 miles) cruising at 15 knots.

The ship was laid down on 24 August 1925, at the Burgerhout's Scheepswerf en Machinefabriek, in Rotterdam, and launched on 30 June 1927. The ship was commissioned on 3 September 1928.

On 11 June 1929, a detachment of marines was sent on Kortenaer to Curaçao, after Venezuelan rebels, led by Rafael Simón Urbina, had raided Fort Amsterdam, in Willemstad, on 8 June.

In 1940, she and her sister Van Ghent guarded five German cargo ships. The ships were relieved by the cruiser Java on 26 April 1940.

She served mostly in the Netherlands East Indies, and when war broke out in 1941, she was at Surabaya.

She took part in Battle of Badung Strait on 18–20 February 1942, where she ran aground on one of the channel shores after temporarily losing rudder control. It was impossible for the Dutch ship to return to the formation, and they had to wait for the next morning tide to free the ship. Kortenaer was sent to Surabaya for repairs.

Main Article: Battle of the Java Sea

She was back in action in time for the Battle of the Java Sea on 27 February 1942, where she played a small role, firing on the Japanese fleet but to no use.

However, Kortenaer was then cemented in history as she was on the receiving end of the longest-ranged torpedo hit in history. At a distance of 22,000 yards (20,100 m), the Japanese heavy cruiser Haguro, which had just crippled the heavy cruiser HMS Exeter with gunfire, fired a spread of eight 61 cm (24 inch) Type 93 torpedoes, one of which hit Kortenaer. Haguro would later sink a fellow Dutch warship, the light cruiser HNLMS De Ruyter, with another torpedo hit during the engagement.

Alexander Sharp, the commanding officer, of the nearby United States Navy destroyer USS John D. Edwards, recorded that "Kortenaer, about 700 yards (640 m) bearing 80° relative, was struck on the starboard quarter by a torpedo, blew up, turned over, and sank at once leaving only a jackknifed bow and stern a few feet above the surface." The Royal Navy destroyer HMS Encounter rescued 113 men from the total of 153, including Lieutenant Commander A. Kroese, and took them to Surabaya.

Over 100 ships and submarines of various countries sank during the war in the seas around Indonesia, Singapore and Malaysia, and many are designated as war graves. There is known to have been illegal scavenging of the wrecks, often using explosives. The wreck of Kortenaer was discovered by specialist wreck divers in August 2004. The wrecks of HNLMS De Ruyter and HNLMS Java had been discovered by the same group in December 2002. In 2016, it was discovered that the wrecks of De Ruyter and Java, and much of Kortenaer had disappeared from the seabed, although their imprints on the ocean floor remained. The Netherlands Defence Ministry suggested that De Ruyter, Java, and Kortenaer may have been illegally salvaged. In February 2017, a report was issued confirming the location and condition of the three wrecks.

• Gardiner, Robert; Chesneau, Roger, eds. (1980). Conway's All The World's Fighting Ships 1922–1946. London: Conway Maritime Press. ISBN 0-85177-146-7.
• Whitley, M.J. Destroyers of World War Two: An International Encyclopedia. London: Cassell & Co, 2000. ISBN 1 85409 521 8.

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