The South Korean Navy has additionally test-fired indigenous anti-submarine torpedoes, but found they weren’t suited for combat assignments after a success rate of only about 60 percent, a military source said Wednesday.

After the torpedo failed to hit its target in the initial test in July of last year, the Navy fired off eight more in a period of five months since last October. Five of them successfully passed the test, while three went missing.

The state-funded Agency for Defense Development created Hongsangeo, or Red Shark in English, over nine years from 2000 with a budget of 100 billion won ($92 million). Some of the destroyers were loaded with the 5.7-meter-long torpedoes in early 2012.

A precision guided weapon like Red Shark should demonstrate more than a 75 percent success rate to be suited for combat assignments.

“Investigations are currently underway. Faulty designs may have led to failures,” the source said, asking for anonymity as he was not authorized to speak to media.

The two-stage torpedo is launched vertically from a destroyer and flies for about 20 kilometers before submerging into the sea to track and destroy a target.

The Navy had planned to deploy the torpedoes in its newest destroyers if they passed the tests, but it is likely to be delayed as military officials and related agencies are currently looking into the cause of the low success rate. (Yonhap News)