The ROKN and Coalition Naval Operations in the Korean War

The Republic of Korea Navy (ROKN) played a vital role during the Korean War as part of US-led coalition naval operations. It was able to contribute significantly to the allied war effort due to its inshore capabilities, local knowledge, and morale. At the same time, however, the ROKN faced major challenges as a newly developed navy, particularly with regard to its equipment, training, communications, and command and control.

When the Korean War broke out in 1950, the ROKN was still in its early stages. It had evolved out of the Joseon Maritime Association, established in 1945, and the Korean Coast Guard, founded in 1946. It included 6,624 sailors and 35 vessels, mostly small US and Japanese minesweepers with a few recently-purchased US submarine chasers. As the war progressed, this small fleet expanded dramatically; by the signing of the armistice it included over 14,000 men and 57 vessels which included new US patrol frigates, torpedo boats, and landing craft. Throughout the conflict, it operated under the authority of the US Commander Naval Forces, Far East and was organized as a task group under the United Nations Blockade and Escort Force.

The ROKN played an important role throughout the conflict as part of the US-led United Nations coalition. In particular, it was a key part of coalition efforts to enforce a blockade against the Democratic People’s Republic of Korea (DPRK). Later in the war, it was also integrated into UN minesweeping effort along the coast. Finally, it also participated in guerilla raids, efforts to control island outposts along the Korean coast, and even occasional coastal bombardment.

In these roles, the ROKN offered a number of important advantages to the coalition. First, ROKN forces filled an important niche, providing small vessels capable of inshore operations. Korea’s coastlines are often rugged and shallow, making it challenging for larger US Navy vessels to operate close to shore. The bulk of ROKN craft were light with fairly shallow drafts, however, especially when compared with the larger surface combatants employed by the US. This meant that the ROKN could often reach where other coalition forces could not. This maneuverability was useful in several ways. It allowed ROKN craft to intercept enemy vessels that were hugging the coast, better enforcing the UN blockade. Furthermore, ROKN vessels could get closer to the shore to better identify targets for allied bombardment. Finally, the ROKN could play a key role in escorting, landing, supplying, or evacuating friendly guerilla forces along the coast or offshore islands. Overall, the ROKN’s ability to operate close to shore in challenging waters contributed to the success of the coalition’s naval effort.   

Second, the ROKN provided the coalition with useful local knowledge. With its intimate familiarity with the local terrain, weather, and population, the ROKN was invaluable for intelligence gathering throughout the conflict. For example, ROKN personnel worked closely with US forces to secure the intelligence needed for MacArthur’s amphibious assault on Incheon. They were also frequently stationed aboard allied vessels where they could interview refugees and interrogate prisoners for intelligence.

Third, the ROKN’s personnel quickly earned a reputation for bravery and ingenuity despite their relative inexperience. US naval officers frequently reported that ROKN personnel were exceptionally proud, spirited, and adaptable with good morale despite their limited experience and equipment. Famously, on the second day of the war, the ROKS Baekdusan intercepted a DPRK transport headed toward Busan with six hundred troops on board. When she struggled to hit the transport amidst rough seas, the Baekdusan boldly pushed closer to the enemy despite the increased risk posed by the enemy vessel’s machine guns. When the Baekdusan’s three-inch gun malfunctioned, she maneuvered closer still to better engage the enemy with her other weapons. Ultimately, the Baekdusan took considerable damage but succeeded due to her bravery, sinking the DPRK transport and securing Busan.

Despite its important strengths and critical contributions to the war effort, the ROKN also had to cope many significant challenges. First, the ROKN often made due with limited, outdated, or poorly-maintained equipment. Most of the ROKN fleet were old US and Japanese vessels that were in poor condition and missing important communication and navigation equipment, sensors, refrigerated storage, and other vital gear. ROKN vessels experienced frequent mechanical failures which often left them unable to contribute to allied operations and required other coalition members to provide costly repairs. Lack of radar and fire control equipment also rendered ROKN forces less combat-effective in surface engagements. Finally, a lack of minesweeping gear and degaussing meant that the ROK could only provide limited support for allied minesweeping operations.

Second, ROKN personnel lacked extensive training and experience when the war broke out. Initially, ROKN midshipmen were taught only briefly for two years at the ROK’s new Naval Academy. Enlisted recruits, meanwhile, were instructed in the basics of following orders and maintaining discipline but little else. Most personnel lacked any combat experience at sea. Ultimately, this meant that the ROKN struggled with tactical and technical missteps throughout the conflict. In one fairly egregious example, during the coalition evacuation of Heungnam port in December of 1950, a ROKN transport loaded with thousands of Korean refugees ran onto a line and was damaged. The vessel was freed and repaired. It then almost immediately fouled its shafts again and was unable to depart. The many refugees onboard desperately needed water and food at this point; several died as they waited for resupply.

Third, communication between the ROKN and coalition forces often proved challenging. Perhaps most problematically, the partners had to confront significant language barriers. Few ROKN officers could speak English and few US Navy officers could speak Korean. Identification and recognition of ROKN vessels also at times proved problematic for allied navies. On several occasions, miscommunication ended in fratricide. Only a few days into the war, on June 29, 1950, the USS Juneau detected a ROKN vessel operating near Samcheok. The Juneau had been told that all ROKN vessels had moved south of the 37th parallel and the ROKN vessel was not flying the ROK flag. As a result, the Juneau opened fire on the ship, destroying it and killing eight Korean sailors.

Finally, the ROKN encountered challenges with respect to command and control over the course of the war. Although the ROKN was placed under the authority of the United Nations command, this command structure did not always function as planned. In particular, problems emerged when Japanese fishermen began to violate ROK President Rhee’s newly-declared ROK-Japan maritime border. Despite having turned over the command of Korea’s armed forces to the United Nations Command, Rhee repeatedly circumvented CTF 95 to order the seizure of Japanese fishermen, prompting several serious diplomatic incidents with Japan which the US had to defuse.

We can look to the ROKN’s experience for examples of the types of strengths and weaknesses which a small, developing navy may exhibit as part of coalition operations. On the one hand, it was able to leverage useful inshore capabilities, local knowledge, and a fierce fighting spirit to great effect. On the other hand, it faced serious deficiencies in terms of training and experience, equipment, communications, and command and control.

The historical experience of the Republic of Korea Navy (ROKN) during the Korean War highlights the need for a multifaceted approach to contemporary ROK-US naval cooperation. First, it is crucial to invest in extensive joint training programs to ensure seamless interoperability and effective communication between the two navies. Language barriers and operational missteps that plagued past operations can be mitigated through regular joint exercises, exchange programs, and the integration of language and cultural training into the curriculum for both ROKN and US Navy personnel. These efforts will build mutual trust and understanding, enabling both forces to operate more cohesively in high-stress situations.

Second, modernization and maintenance of naval equipment should be prioritized to ensure fleet readiness and combat effectiveness. Given the historical challenges faced by the ROKN with outdated and poorly maintained vessels, contemporary cooperation must include support for technological upgrades and the provision of state-of-the-art equipment. Additionally, establishing robust and clear command structures is essential to prevent operational ambiguities and diplomatic conflicts, as seen during the Korean War. Unified command protocols will facilitate coordinated responses and strategic alignment, particularly in sensitive or high-stakes scenarios. By addressing these areas, contemporary ROK-US naval cooperation can leverage the lessons of the past to build a more resilient and capable maritime alliance capable of addressing present and future security challenges.