PORTLAND (AP) – After three years, a man who works at the Portsmouth Naval Shipyard has found a submarine sunk by the Navy during World War II for training purposes.

Joe Cushing – who lives in Strafford, N.H., – won’t disclose the sub’s exact location, but says it’s about 12 miles at sea from Portland, Maine.

Cushing says the sub – called “S-21” – was used by the Navy to train pilots and destroyer crews to detect enemy submarines.

He started his search in federal archives, and later learned that a salvager had found the sub in the 1960s but quit after one of his divers got killed.

Cushing got help from another technical diver and a sonar expert before hitting paydirt.