Japanese submarine Ro-33


The Japanese submarine Ro-33 was a Kaichū type submarine of the K5 sub-class built for the Imperial Japanese Navy during the 1930s.

Design and description

The submarines of the K5 sub-class were versions of the preceding KT sub-class with greater surface speed. They displaced surfaced and submerged. The submarines were long, had a beam of and a draft of. They had a diving depth of.
For surface running, the boats were powered by two diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a electric motor. They could reach on the surface and underwater. On the surface, the K5s had a range of at ; submerged, they had a range of at.
The boats were armed with four internal bow torpedo tubes and carried a total of ten torpedoes. They were also armed with a single 8 cm/40 3rd Year Type naval gun| L/40 anti-aircraft gun and one Type 93 anti-aircraft machinegun.

Construction and career

Commissioned on October 7, 1935 the submarine saw action for Imperial Japanese forces during the Pacific Campaign of World War II. On 7 August 1942, Ro-33 sank the Australian motor vessel Mamutu in the Gulf of Papua near Murray Island, Torres Strait, with the loss of 114 lives. After shelling Mamutu until she was sinking, Ro-33's commander, Shigeshi Kuriyama, then ordered his gunners to open fire on the survivors, men women and children, as they struggled in the water. Of the full complement of passengers and crew, there were only 28 survivors. The submarine was sunk near Port Moresby, Papua New Guinea with all hands by the Royal Australian Navy destroyer Arunta at on August 29, 1942.