Member of Class
O 19
O 20
Sister Ships
O 19, O 20


O 20 surfacing
(Photo: © Collection G.D. Horneman).
O 20 surfacing (Photo: © Collection G.D. Horneman).

For additional photos and information please check the 'related pages list' at the bottom of this page.


15 June 1936: K XX is laid down at the Wilton-Fijenoord shipyard in Rotterdam.

While under construction the submarine is renamed into O 20 (exact day/year of the renaming is unknown).


31 Jan 1939: O 20 is launched

28 Aug 1939: O 20 is commissioned to the Royal Netherlands Navy.

28 Aug (2 Sep is not correct) 1939 - 9 Nov 1940: O 20 is under the command of Ltz. I  A.J. Bussemaker.

O 19 and O 20 were the first boats in the world equipped with the "getrimd diesel systeem" or "snort system". This system allows the submarine to run its diesels while being submerged in order to recharge the batteries, ventilate the boat and cover some useful miles under water.

2 or 3 Oct 1939: A squadron departs from the Netherlands and heads for the Netherlands West  Indies. For safety reasons (floating mines), and because the Netherlands are still neutral, it is decided to take a route around Scotland and England.

The squadron consists of: O 20, O 15 and van Kinsbergen.

9 Oct 1939: Matroos D. Termoshuizen from Rotterdam is washed overboard. Weather conditions are very bad and while throwing some human garbage overboard (the toilets could not be emptied the normal way) an extremely large wave washes the sailor overboard. She ships of the squadron start searching immediately, but D. Termoshuizen is not to be found. After several hours the squadron continues its journey.

Exact location of this incident is unknown. It is also unknown why this incident is not listed in any Submarine Service listings. 

The squadron arrives in Ponta Delgada (Portugese Azores). Only know it is possible to inspect O 20's deck for damage (inflicted by the severe weather conditions). It turns out that several 'hatches' below the top casing are gone and that several side plates of the top casing are damaged. The crew conducts the necessary repairs themselves and after a couple of days the journey is continued. During the next leg, to Curaçao, the squadron exercises with many other vessels.

29? Oct 1939: The squadron arrives in Curaçao. The O 15 will stay in Curaçao and O 20 (and possibly the van Kinsbergen as well) continue their journey to the Netherlands East Indies.

23? Dec 1939: O 20 arrives in the Netherlands East Indies, she has taken the route via the Panama Canal.


10 May 1940: Germany attacks the Netherlands.

9 Nov 1940 - 31 May 1941: O 20 is under the command of  F.J.A. Knoops.


16 Feb 1941 - 28 Apr 1941: The Cdt Submarine Flotilla, J.A. de Gelder, is stationed on board the O 20.

20 Sep 1941 - 19 Dec 1941: O 20 is under the command of  Ltz. I  P.G.J. Snippe.

7 Dec 1941: The USA declares war on Japan after Japanese forces attack Pearl Harbour. Approximately 7 hours after the attack the Netherlands also declares war on Japan.

7 Dec 1941: The CZM radios (#109 1207-2215) that "War with Japan has broken out".

8, 11 or 12 Dec 1941: O 20 is based at Singapore Submarine Base and is under British Eastern Fleet operational control.

12 Dec 1941: The CZM orders (Tel. #240) O 19 and O 20 to position 00°00'N-105°30'E. At this position the subs will be under the command of the CinCEF. The CinCEF orders both submarines to sail to Singapore.

O 20 has already reported (time and date of report unknown) the following defects to the CZM:

- Temporarily repaired vent pipe in tank III (often filled with fuel).
- Leaking screw shaft.
- Heavily corrode underwater exhaust pipe. 

13 Dec 1941 between 12:00 - 16:00 hrs: O 20 arrives at the Singapore Naval Base wher she loads 40 tons of fuel and some small defects are repaired.

14 Dec - 19 Dec 1941: O 20 patrols the South China Sea, one ship is attacked. O 20 will be lost during this patrol.

14 Dec 1941: C-in-C orders/reports (#340 0821/14Dec'41) that a force of 2 battle ships and 6 cruisers was reported in position 7º32'N-106º18'E at 0654z 14 December. O 19 and O 20 are to endeavour to gain on a position covering the advancing enemy, should they pass between position assigned to K XVII and the shore.

14 Dec 1941 between 12:00 - 16:00 hrs: O 19 and O 20 depart from the Singapore Naval Base. At 17:40 hrs the subs pass Horchlight and in the evening the O 19 and O 20 continue their transit separately.

16 Dec 1941: The CinCEF reports (Tel. 1001/16dec41) that 13 transports off Patani and 20 transports off Kota Baru have been spotted.

In the evening the O 20 is ordered to a new patrol area. The area is the a box (30' long and 20' wide) off Malacca's East coast. Kota Baru is approximately in the middle and on the West side of the patrol box. The area will be a 'sanctuary' for allied planes. The average water depth in this area is only 45 meters.

17 Dec 1941 in the morning: O 20 is in her patrol box and +/- 10' off Kota Baru. She continues patrolling at periscope depth.

Some time between 08:00 and 12:00 hrs O 20 spots a Japanese destroyer and some time between 12:00 and 16:00 hrs she has to dive because of a spotted Japanese float plane.

18 Dec 1941: During the night the sub surfaces and reloads her batteries.

In the morning, as well as in the afternoon, the O 20 spots a Japanese destroyer.

19 Dec 1941: During the night the O 20 surfaces and reloads her batteries. At 03:00 (MJT) the sub is back in her patrol box. The O 20 is now +/- 25 miles off Kota Baru, she submerges and 'hugs the bottom' at +/- 40 meters. This in order to give the crew the opportunity to rest.

At 05:00 hrs: High speed screw noises are heard but the commander decides not to respond because it is still dark and because the enemy ship is not nearby.

At 05:45 hrs: the submarines surfaces, but no ships are spotted.

At 07:00 hrs: At a distance of 6 miles the O 20 spots 2 Japanese transports, escorted by 2 destroyers, sailing in the direction of Kota Baru. The commander tries to get within 'launching distance' but he does not succeed.

O 20 keeps patrolling the same area and she spots two destroyers at the Southern horizon. Between 05:00 and 12:00 hrs a third destroyer joins the other 2. The three destroyers are the Japanese Ayanami, Yugiri and Uranami.

At 11:00 hrs: Although the O 20 is sailing at periscope depth she is spotted by enemy planes. The planes drop two bombs and O 20 goes deep without being damaged. After half an hour the sub returns to periscope depth and takes a look around. They spot two destroyers zig-zagging 400 meters aft of the sub. O 20 submerges immediately and 'hugs the bottom' at 42 meters. But during the dive depth charges are already exploding. These explosions damage the listening device, but fortunately the device can be repaired. The sub rigs for silence and additional oxygen is released in the boat.

Some sources (including some first hand accounts) state that the decision to recon the bay and attacked during day light was a bad decision of the commander.

The destroyers drop depth charges at regular intervals (approximately 8 depth charges every half hour). One of the runs results in 9 explosions right above the submarine. But as far as the crew knows the submarine is not damaged. (After the war it came out that the Japanese set their depth charges at 30 meters because the next setting would have resulted the depth charges ending up on the bottom).

In order to get away from this 'hot spot' the commander orders full ahead and all planes are set to 'rise'. But with out blowing tank III inboard, the sub can not get loose from the sucking mud on the seabed. The sub sneaks to a spot 800 meters away. In order to maintain depth tank III has to be vented outboard, which results in an air bubble rising to the surface.

This 'sneaking away' is repeated for several times (probably 6). As far as the commander can  tell the attacks are always at the subs former position. Therefore he and the Hoofd Machinekamer (Head Engineer) conclude that the sub must be leaking fuel which is spotted by the destroyers. (See also the list of reported defects).

Around dusk the depth charge attacks stop and at 17:30 hrs screws are heard at bearing N285°E.

The commander wants to surface after dark in order to try to get away with the diesels running at full speed. He does not want to submerge when being spotted by the enemy because the batteries are almost empty (only 500Ah of 6000 Ah is left).

At 20:45: A strange sound is heard. It sounds like heavy rain on a metal plate. (This sound is actually the noise of a new Japanese detection device, but at the time this is unknown to the crew).

Tank II and III are blown and the submarine surfaces at quit an angle (25°) while the motors are at full speed. Because of the leaking screw shaft there is a considerable amount of water in the engine room. (See also the list of reported defects). The bilge pumps are switched on and aft tank (Y) is blown. 

Because of the over pressure in the boat (300mm) the boat has to be vented before it is possible to open the conning tower hatch. As soon as the hatch is open the diesels are started and some time later (after the order is given) the hydraulic clutch is kicked in. During blowing of the main ballast tanks the diesels are already running at max. speed (+/- 19 knots). The submarine hurries away from the area on a N45°E course.

After opening the conning tower hatch and the aft battery compartment hatch the gun crew prepares the deck gun, but no enemy vessels are spotted. (The commander does not order the crew to man the 40mm machine guns prepare the aft tubes or install the 'night aiming device' of the deck gun).

The commander decides to empty tank IV (filled with fuel), in order to go even faster, but this also results in the boat sitting higher in the water. Now the exhaust pipes of the SB diesel are not submerged anymore. These pipes where already damaged (See also the list of reported defects) and the depth charge attacks did not do them any good as well. This combination of sitting high in the water and the damaged exhaust pipes results in a 'rain' of sparks shooting in the air. The commander decides not to switch the diesel off.

All tubes are prepared. After 20 minutes of running at max. speed the O 20 is spotted and 'caught' by a large searchlight. The SB diesel is switched of and both aft tubes are fired. But because of the fact that the boat is still turning both torpedoes miss their target. In the meantime the destroyer opens fire with a double gun. Fortunately the shots miss the submarine.

According to some sources only the port side torpedo was ordered to be fired, the starboard torpedo launched itself due to vibrations caused by running at this high speed.

Because the destroyer is in the blind spot of O 20's deck gun the submarine can not return fire immediately. Now the commander orders the crew to man the 40mm guns as well. Only after the fourth enemy shell, of which some pieces hit the tower and the casing, the submarine is able to return fire with her deck gun. The distance is now +/- 1500 meters. 

According to some sources several people where wounded/killed by this fourth shell. But according to some first hand accounts (including some officers) this is not true.

Only one shot can be fired because the commander decides there is no way to escape and orders all hands (complete with their Draeger vests) on deck  He wants to scuttle the submarine and with an interval of 2-3 seconds main ballast tanks 1 through 6 are flooded. With the diesels still at full speed the submarine disappears below the surface.

According to some sources the deck gun crew (that only had time to fire one shell) is washed off the deck. The same sources (including some officers) and some newspaper articles state that the loss of the O 20 was possibly unnecessary and maybe only the result of bad calls of O 20's commanding officer.

The Japanese destroyer sails with a speed of 20 kts through the middle of the group of swimming submariners and drops several depth charges nearby. She must have thought the sub was doing a crash-dive.

Estimated position is 25 miles east of Kota Bharu (east coast of Malaya).

At 23:00 hrs: After a head count it turns out that seven men, including the commander (who was not wearing a Draeger vest), are missing. Officially it is unknown how these men are lost. Maybe they have been hit by the destroyer sailing through the group of men or maybe their Draeger vests malfunctioned. Since the commander was not wearing a Draeger vest it is very likely that this is the reason why he was lost.

According to some first hand accounts (including some officers) there was quite some panic during the scuttling 'operation'. Because of this panic the crew forgot to warn 6 people in the engine room. These people where Sergeant torpedomaker J.H. van Bastelaar, Sergeant machinist M. Tilro, Korporaal machinist G.J.H. van Uden, Stoker olieman H. Lammers, militie olieman A.J.J. Bechtold and Matroos 1e klasse J.P.S Drevijn.

The Uranami does not start to rescue the survivors right away. This is probably because she is afraid to get torpedoed and wants to wait for daylight. The destroyer does drop a depth charge every now and then to keep the sharks away.

20 Dec 1941 at 07:30 hrs: The Japanese destroyer Uranami rescues 32 survivors. 

When the O 20 went down and the survivors were made POW's, the officers were moved to a jail in Hong-Kong while the lower echelons were put to work in a camp on Kyushu. Of the total of 32 POW's as POW's.  Two of the officers, Hordijk and Idema escaped on the 28th of January 1942 from their prison through the sewer system, finally crawling out at the beach of Hong-Kong. Thanks to their knowledge of weaponry they survived. They fell into the hands of the resistance which had arms it was unfamiliar with, and the two Dutch officers could explain how to use these arms in exchange for transport to the mainland. They walked from Hong-Kong to ?Peking? where they contacted the Dutch chargé d'affaires who arranged for them a transport to Colombo (Ceylon) where both reported on the 18th of April 1942 and found themselves again on a Dutch submarine a couple of months after their escape.

The names of the lost crew members are listed on the Lost Dutch Submarine Service Personnel page.


12 June 2002: Dutch divers locate the wreck of the O 20.

A group of 7 divers, all associated with the IAHD, participated in a dive expedition in June 2002 to look for and identify a Dutch submarine that sank after being attacked by the Japanese on December 19 1941.

Research was done by mr H Besançon, son of the commander of the Hr.Ms. K XVII, one of the other submarines lost by the Dutch navy during WW2. The expedition leader was Klaas Brouwer, CEO of the IAHD. Dive leader was Michael Lim from Singapore who also is the owner of the chartered vessel Mata Ikan. Three of the participating divers have a physical handicap. Nevertheless they participated in the search, only limited by seasickness.

In order to identify the wreck the team has made photo and video shots of the wreck. The team also removed a 'deck phone' from the submarine. The Dutch Navy has positively identified this wreck as the O 20.

O 20's deck phone, June 2002. (Photo: © IAHD Foundation). O 20's deck phone, June 2002. (Photo: © IAHD Foundation).

The wreck is located approximately 35 miles North-East of Kota Bharu (Malaysia) at a depth of 44 meters. The divers report that the masts are not visible and that the snort is gone, the bridge is damaged so heavily by shells that one can easily look through it, the bridge hatch is open and that the hatch just in front of the bridge is also open.

Surf to diving the O 20 wreck for more photos of this expedition

Early July 2002: The Dutch Press Agency ANP releases the following message: "....Dutch divers have found the wreckage of the Dutch submarine Her Majesty's O20 off the East coast of Malaysia. The Dutch submarine was lost during a battle with Japanese submarine hunters. In the fight on December 19, 1941, seven crew members lost their lives.  Out of respect for the dead crew members and their relatives, the seamen's grave will not be disturbed...."




 O 20 related pages
O 19 class specifications
O 20 boat history
O 19 and O 20 under construction
Diving O 20
The story of Submarine O 20
O 20 related books







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