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Trigger’s Rewarding


The USS Trigger’s assignment for her third war patrol was to conduct reconnaissance of shipping along the twenty-fathom curve off Inubo Saki, on Honshu’s eastern coast. She was also assigned the job of planting nineteen Mark 12 mines in that area. Following completion of her reconnaissance objective, her captain, Roy S. Benson, decided to lay the mines at night while submerged. A northern field would be laid first and then a southern field, each to be perpendicular to the courses on which the ships observed passing Inubo Saki were headed. Shortly after they started to lay the second minefield, a freighter was sighted approaching from the southward heading directly for Trigger. Benson gave the order to curtail laying the mines until the freighter had passed. As it came nearer Benson could see it was a large freighter with a small escort vessel inshore from it. He noted that its position could have been perfect for a torpedo attack with the stern tubes were it not for completion of the mine plant as his immediate objective. About five minutes after the freighter passed astern there was a violent explosion. The periscope showed the freighter lying in the trough of the seas and rolling in the heavy swells violently while the escort vessel circled it. Its back had been broken and amidships the deck was awash. About ten feet of the stern was above water and the bow was high out of the water. It sank quickly. Clearly it had struck one of the mines in the northern field. The escort vessel appeared to be a motor torpedo boat. Benson reckoned there would soon be more antisubmarine vessels in the area so he ordered retirement into deep water. Soon another violent explosion was heard. Benson speculated that the motor torpedo boat or perhaps another vessel had struck another mine. A huge cloud of smoke was observed rising above the minefields. It would be senseless to try to complete the second plant. The enemy knew there was a submarine in the area even if they did not suspect there was a minefield. Thus Benson’s decision to hold his torpedo fire against the large freighter was rewarded with the unusual experience of watching the vessel blow up in the minefield he had just planted. John D. Alden identified the freighter observed by Benson as the 3,893-ton cargo ship Mitsuki Maru.

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