HNLMS O 20

O 20
Career
Laid down:	June 15, 1936
Launched:	January 31, 1939
Commissioned:	August 28, 1939
Fate:	Sunk on December 19, 1941
General characteristics
Displacement:	Standard: 982 tons Surf: 1109 tons Submerged: 1491 tons
Length:	264 ft 9 in (80.70 m)
Beam:	24 ft 4 in (7.42 m)
Draft:	12 ft 8 in (3.86 m)
Propulsion:	Two 7-cylinder Sulzer diesel engines, 2-stroke & two 2650 hp motors driving two shafts
Speed:	Surf: 19.5 knots (36.1 km/h) Submerged: 9 knots (17 km/h)
Range:	Surf: 10,000 nmi (20,000 km) at 12 knots (22 km/h) Submerged: 27 nm at 8.5 knots (15.7 km/h)
Complement:	40
Armament:	14 torpedoes, incl. 6 reloads, and 40 mines, 40 mm machine gun

The O 20 was a Dutch O 19-class submarine in the Royal Netherlands Navy that saw service during World War II. O 20 along with her sister ship O 19 were the first boats in the world to be equipped with a "getrimd diesel systeem" or "snort system" that allowed the submarine to run its diesel engines while submerged.

O 20 was laid down June 15, 1936 as the K XX. After which at some point she was renamed O 20. She was launched on January 31, 1939, and on August 28 of the same year she was commissioned and assigned to the command of Ltz. I A.J. Bussemaker.

Pre-WWII

She was put into a squadron that consisted of two submarines: O 20 and sloop Van Kinsbergen. This squadron departed the Netherlands for the Netherlands West Indies on either October 2 or 3rd 1939.

By December 23, 1939 O 20 reached the Netherlands West Indies via the Panama Canal.

World War II

• On May 10, 1940 Germany attacked the Netherlands

• On May 31, 1941 the O 20 was put in the command of F.J.A. Knoops followed by Ltz. I P.G.J. Snippe on September 20, 1941.

• December 7, 1941, the Japanese attack Pearl Harbor, brought the US into the war. The Netherlands followed suit hours later.

• By early December 1941, O 20 has been stationed at Singapore Submarine Base and is under the command of the British Eastern Fleet.

The sinking of O 20

On December 14, 1941 O 20 was under orders to patrol the South China Sea. On the 14th, two battleships and six cruisers were sighted, O 20 and O 19 were given orders to gain position on the enemy ships. The two subs would split paths en route to the target when 13 transports were spotted off Patani, Thailand and another 20 off Kota Bharu, Malaysia.

Given a new patrol route, O 20 spotted Japanese destroyers off and on from December 17 to 19th. On the 19th at 7:00, she spied two Japanese transports being escorted by two destroyers. In a few hours a third destroyer joined them. These destroyers were the Ayanami, the Uranami, and the Yugiri.

Spotted

At 11:00, O 20 was spotted by enemy planes which dropped two bombs on the submarine and alerted the destroyers to her presence. The submarine dove and was able to avoid the bombs, but the destroyers began to drop depth charges which soon destroyed the sub's listening device and caused other minor damage.

The destroyers scanned the bay for O 20, dropping eight depth charges every half hour. Some of these detonated directly above the submarine, but were set to detonate too shallow to badly damage it. (It turned out that the next deepest setting would have buried the charges in the mud)

Retreat

In order to escape, the commander ordered full speed ahead with all planes set to rise, but O 20 had become mired in the mud. An air tank was blown in an attempt to loose the submarine from the seabed, but also ended up alerting the destroyers to O 20's position by releasing bubbles.

That night, the commander attempted to surface to escape at full speed, but was detected by a new Japanese sonar. Two more tanks were blown and the sub surfaced at a 25° angle and engines were set to full speed. Because of some pre-existing defects O 20 began to take on water at the screw shafts.

The hatch was opened and with no enemy ships in sight, the machine guns were not manned or prepared. The commander decided to dump a fuel tank in order to escape even faster, which rose the sub even higher in the water exposing the diesel exhaust pipes. Due to more pre-existing damage coupled with damage from the depth charges, the pipes began to spark, giving away the O 20's position to anyone who looked in her direction. The commander decided to do nothing.

Showdown

After 20 minutes of running in this manner, one of the destroyers (the Uranami) closed in, spotted the O 20 with her searchlight and opened fire. The shot missed. The commander now ordered the machine guns manned, and the ship turned about to fire the torpedoes. She couldn't get in position until after the fourth volley, which struck the Conn Tower and main hull. O 20 returned fire with the 40 mm machine gun. The port side torpedo was ordered to be fired, but because of extreme vibrations due to the speed, both sides fired. Both torpedoes missed.

Defeat

The sub badly damaged, the commander decided then that there was no hope for escape, and ordered all hands on deck. He then ordered the sub be scuttled by flooding all the main ballast tanks. The sub descended under the water, still running at full speed, as the crew floated above. Uranami, apparently not noticing that the crew had abandoned ship, followed the sub, cutting through the crew at 20 knots (37 km/h), and dropped depth charges on the now abandoned sub.

After daylight, Uranami rescued the 32 survivors, having dropped depth charges throughout the remainder of the night to keep sharks away. Seven men, including the commander were found to be missing. The commander was known to not have been wearing his life vest, which may have also been the cause of the other six deaths. An alternative suggestion is that since the six men all worked in the engine room, they may have not been warned in time to evacuate the ship before it was scuttled.

The shipwreck

On June 12, 2002 a group of 7 Dutch divers associated with the International Association for Handicapped Divers participated in a dive expedition to locate the O 20. The dive, led by IAHD CEO Klaas Brouwer, Dive Leader Michael Lim, and Mr H Besançon, also included three physically disabled members.

The wreck is located approximately 35 nautical miles (65 km) NE of Kota Baru, Malaysia at a depth of about 144 ft (44 m). The divers report that the masts are no longer visible, the snort is gone, and that the bridge was shelled so badly it could be seen through easily. The divers retrieved a deck phone from the sub in order to positively identify it, but left the wreck alone, as it was likely the gravesite of six seamen.

References

• Dutch Submarines: The submarine O 20
• Dutch Submarines: The O 19 submarine class