In 1941, the Dutch fleet in the Dutch East Indies faced what seemed like certain destruction against the Japanese advance. But one man refused to accept defeat: Conrad Helfrich. Instead of a desperate defense, he chose constant, hard-hitting counterattacks at sea, making submarines his primary weapon. Some called his plan brilliant; others called it reckless.
What followed became one of the most underestimated naval campaigns of World War II in Asia. Helfrich was born in 1886 in Semarang, Dutch East Indies. He trained as a naval officer, specializing as a torpedo officer, and held key positions in both the Netherlands and the Indies. By the 1930s, he had become a major figure in the naval leadership, serving as chief of staff and later commander of naval forces.
He pushed for a powerful fleet built around large artillery ships and battlecruisers to defend the archipelago. In 1939, he became commander of naval forces in the Dutch East Indies. When the war broke out, Germany had already conquered the Netherlands, so the planned construction of battlecruisers could not happen. Helfrich pivoted to a more flexible strategy: rapid, short attacks designed to achieve local superiority before withdrawing.
It was guerrilla warfare at sea. Submarines played the central role. Cooperation with Allied navies was difficult, partly because large-scale exercises were politically sensitive—the Allies didn’t want to provoke Japan. That changed in December 1941, when Japan attacked Pearl Harbor, the Philippines, and Malaya.
The Allies declared war, but they had seriously underestimated Japanese military capabilities. Naval bases in the Philippines, Malaya, Singapore, and the Dutch East Indies became vulnerable. With outdated submarines and limited reserves, the Dutch tried to slow the Japanese advance as long as possible before the Allies were forced to retreat to Western Australia. The Americans operated 29 submarines near Manila, but after the base fell, they retreated to Surabaya on Java and Darwin on Australia’s northern coast.
The Dutch had been operating submarines from Surabaya since World War I. By early 1942, 15 Dutch submarines were deployed to defend their own bases and British Singapore. The Japanese advance continued relentlessly. Singapore fell on February 15, 1942.
On the night of February 19, an Allied fleet attacked a Japanese invasion force near Bali in the Battle of the Badung Strait. The same day, Japanese aircraft launched a massive attack on Darwin’s harbor and airfields to prevent the Allies from using those bases against the planned invasions of Timor and Java. On February 27, Japanese amphibious forces assembled for the attack on Java. The main ABDA fleet, under Rear Admiral Karel Doorman, departed Surabaya to intercept them.
That led to the Battle of the Java Sea. Doorman’s combined strike force repeatedly tried to attack the Japanese fleet, but every attempt was repelled. The Japanese inflicted such severe losses that Allied naval operations in Asia were virtually crippled. Doorman himself was killed in the battle.
Japanese ground forces then invaded Java. Dutch troops, supported by remaining British units, fought for another week, but Japanese superiority proved decisive. On March 9, 1942, the ABDA forces surrendered. The Americans and Dutch withdrew with the intention of using Darwin as a new base.
But upon arrival, American submarine commanders discovered that Darwin was unsuitable—the harbor was vulnerable to air raids and the town lacked infrastructure. They moved to Exmouth Gulf, which was also unsuitable, and finally relocated to Fremantle in Western Australia, where they continued the fight. At the start of the war, the Royal Netherlands Navy operated 30 submarines. Some were in Europe, others in the Dutch East Indies.
After the German invasion of the Netherlands, the fleet was dispersed across British bases. Submarines that could no longer be used were scuttled, while operational boats were placed under British command. Seven Dutch submarines operated in the Gulf of Siam under British control; three others operated near Borneo under Dutch command. The Dutch had built special K-class submarines for tropical and colonial waters, along with more modern O-class boats that could operate in both cold and warm seas.
When war broke out with Japan, 12 K-class and three O-class submarines operated from Surabaya. Only eight were relatively modern. The others were outdated and required extensive maintenance. Several decommissioned submarines were even brought back into service.
Under Helfrich, Dutch submarines achieved remarkable successes. Between 1941 and 1942, they sank an estimated 20 to 30 Japanese ships—mainly transports, supply vessels, and several warships. Most of these successes came in the first months of the war. This earned Helfrich the nickname “Ship-a-Day Helfrich.
” The nickname was partly propaganda, of course—a Japanese ship wasn’t literally sunk every single day. But compared to other Allied navies in Southeast Asia, the Dutch submarines were strikingly effective. One of his commanders was Anton Bussemaker, captain of the submarine O 16. During the night of December 11–12, 1941, Bussemaker launched a daring attack in Patani Bay, Malaya.
With exceptional navigation, he torpedoed four Japanese troop transports. But the losses were severe. Several Dutch submarines were lost in combat in the South China Sea and during air raids on Surabaya. Bussemaker’s O 16 was also lost shortly after the attack, striking a naval mine near Malaya.
As the Allies retreated to Surabaya and Cilacap on Java, the situation became increasingly hopeless. Constant Japanese air attacks and the lack of reinforcements made it impossible to hold their position. During the retreat, the Dutch destroyed as many installations as possible to keep them out of Japanese hands. Some Dutch submarines escaped to Colombo, Ceylon—present-day Sri Lanka—while others sailed to Fremantle, Australia, where they operated under American command.
On March 2, 1942, Helfrich was ordered by the Governor-General to leave for Ceylon. He spent the rest of the war in Colombo, serving as Dutch commander of the armed forces in the East. The position was largely administrative and gave him little satisfaction. Tensions arose with the civilian authorities of the Dutch East Indies, especially Minister van Mook, and with elements of the Royal Netherlands East Indies Army that had formerly fallen under his command.
The disputes concerned plans by the colonial government to create “authority troops” and an oil battalion to restart the Indonesian oil industry quickly after the Japanese occupation ended. The government also wanted to train large numbers of administrative officials, partly by drawing personnel from the armed forces. Helfrich cooperated, but reluctantly, because he believed these plans conflicted with Allied warfare demands and weakened the Dutch position. The Dutch submarine service remained active after the fall of the Dutch East Indies between 1942 and 1945, though on a smaller scale and mostly under Allied command.
Submarines like the Zwaardvis operated from Fremantle and participated in broader Allied operations in the Indian and Pacific Oceans. For Helfrich, this period was frustrating. He no longer had an active operational command and could only observe military operations from a distance. On September 2, 1945, Helfrich signed the Japanese surrender on behalf of the Netherlands aboard the USS Missouri in Tokyo Bay.
Shortly afterward, on October 1, he arrived in Batavia. Until January 1946, he remained commander of Dutch armed forces in Indonesia. He strongly supported restoring Dutch authority and rejected any cooperation with Sukarno and the Indonesian nationalists. After the Linggadjati Agreement, he issued an official protest to the Dutch government.
He and others feared the unity of the kingdom would be undermined and warned they might no longer be able to serve in good conscience. They discussed their concerns with Queen Wilhelmina, but this led to few concrete changes. Meanwhile, Helfrich had been appointed commander of naval forces in August 1945, a role he formally assumed in the Netherlands in 1946. Until his retirement in 1948, he helped direct the reconstruction of the Royal Netherlands Navy, focusing on fleet planning and naval bases.
After retiring, he remained politically active in organizations advocating continued ties between the Netherlands and Indonesia. In the end, this proved unsuccessful—the Dutch government recognized Indonesian sovereignty in 1949. Helfrich would have preferred Indonesia to remain part of the Kingdom of the Netherlands. But was that ever possible?
Could the Dutch have won the Indonesian War of Independence?
