Qualla: Japanese Submarine Ro-103

Japanese Submarine Ro-103: Introduction

Thu, 16 Apr 2026 00:00:00 GMT

On 28 July 1943, Ro-103 transmitted a brief sighting report from somewhere north of New Georgia. Then nothing. She had been at sea sixteen days. She carried forty-three men. No survivors were ever found, no wreckage identified, no enemy claim convincingly matched her last known track. Eighty years later, the circumstances of her loss remain unresolved - one of dozens of Japanese submarines that simply ceased to transmit during the savage Solomons campaign and joined a long undersea roster of the missing.

Japanese Submarine Ro-103: A Small Boat for a Small War

Thu, 16 Apr 2026 00:00:00 GMT

Ro-103 was not one of the long-range hunters that harried the American coast. She was a coastal submarine of the Ro-100 class, derived from the earlier Kaichu type, built for island warfare rather than oceanic patrol. Sixty meters long, six meters in the beam, displacing just 601...

Japanese Submarine Ro-103: Laid Down Before Pearl Harbor

Thu, 16 Apr 2026 00:00:00 GMT

Her keel was laid on 30 June 1941 at the Kure Naval Arsenal, still months before Japan's war became the world's war. She went into the water as Ro-103 on 6 December 1941 - the day before the attack on Pearl Harbor, though her builders had no way of knowing it. Commissioning came ...

Japanese Submarine Ro-103: Aground in the Trobriands

Thu, 16 Apr 2026 00:00:00 GMT

Her war began badly. The first patrol east of Port Moresby turned up nothing. Then came the disaster of the Bismarck Sea, where Allied aircraft and PT boats annihilated a Japanese convoy carrying the 51st Division toward Lae, sinking all eight transports and half their destroyer ...

Japanese Submarine Ro-103: The Attacks That Counted

Thu, 16 Apr 2026 00:00:00 GMT

Over the next three months, Ro-103 made routine patrols near Guadalcanal and east of the Solomons, all of them uneventful. Then on 23 June 1943, fifty nautical miles south of San Cristobal, she finally found what she had been built to kill. A convoy of three transports with three...

Japanese Submarine Ro-103: A Signal, Then Silence

Thu, 16 Apr 2026 00:00:00 GMT

After a week in port, she sailed on her fifth patrol. Orders shifted mid-voyage from Rendova to Vanga Bay off Vangunu. Between 15 and 24 July she sighted Allied forces three times, never closing to firing position. On 28 July 1943 she transmitted a sighting report from north of N...