Uploaded January 2026 | Updated September 2026, 2 weeks ago
During WWII the US seeded thousands of sea mines in Japanese ports harbors and waterways. Around 3,000 of these mines were the unsweepable pressure-magnetic triggered type. International law requires mine clean-up is the responsibility of the belligerent who seeded the mine. The US was responsible for mine cleanup. All of the pressure-magnetic triggered mines incorporated a sterilization feature which would render them inert 150 to 190 days after planting. To make sure they are harmless though, the US developed a fleet of 3 modified ships to act as Guinea pigs, sailing over mine fields to detonate the pressure-magnetic triggered mines. The ships completed 300 missions from November 1945 to May 1946. They only detonated a single pressure mine in Dec, 1945 during their missions.
During WWII the US seeded thousands of sea mines in Japanese ports harbors and waterways. Around 3,000 of these mines were the unsweepable pressure-magnetic triggered type. International law requires mine clean-up is the responsibility of the belligerent who seeded the mine. The US was responsible for mine cleanup. All of the pressure-magnetic triggered mines incorporated a sterilization feature which would render them inert 150 to 190 days after planting. To make sure they are harmless though, the US developed a fleet of 3 modified ships to act as Guinea pigs, sailing over mine fields to detonate the pressure-magnetic triggered mines. The ships completed 300 missions from November 1945 to May 1946. They only detonated a single pressure mine in Dec, 1945 during their missions.
