Early February 1943
Intelligence services provided an extremely valuable nugget of information to Fleet Command in the early days of February. The call sign that hitherto been identified to the light carrier Zuiho had been located some350-450 miles to the North East of Midway Island. Needless to say this caused a minor panic at Pearl Harbour and immediate orders were given to all incoming convoys from the mainland, and there were a lot of them, to reroute immediately and to steer away from the North East approaches of Pearl and to seek new routes further to the West and South West. An LB-30 squadron was transferred from Adak Island into Pearl to use their long legs to scour the ocean while Catalinas at Midway revectored their search arcs and a 100% effort was asked for and given. 8 submarines, recently upgraded with the latest submarine radar units, enroute from Pearl to Midway, were also ordered to move into the waters the suspected enemy ships were moving into.
Two days later a call sign of a destroyer were also detected, this time much further to the East of the last detection. Something was definitely up, Several picket ships of older class destroyers and small range minesweepers were sent on an arc stretching from due West to NNE. Increased detection of enemy submarines in the approaches to Pearl also compounded the sense of alarm and paranoia gripping Hawaiian Command. The first visual sighting of an enemy ship, and confirmation that something was up came when an auxiliary cruiser opened fire on a two ship convoy that was the regular mail delivery from San Francisco to Pearl. This first engagement came to naught as several shots were exchanged at long range but no hits were recorded. The next day, however, using the ever increasing weather as cover, the Japanese vessel was able to sneak up closely and sink the John C.Calhoun . Attempts to intercept this raider with destroyers and planes were unsuccessful.
Final proof and confirmation came the next day when LB-30’s and submarines were able to triangulate radio traffic and establish a solid position. LB-30’s were tasked to focus their search on a small angle of ocean and one lucky craft, at the extreme limit of its range sighted the Japanese ships smack in the middle of the US backyard!
Several hours later Mayday signals were received from the Minesweeper Herald, claiming she was under heavy aerial attack. Likewise the Captain of the picket destroyer Allen reported that his ship was sinking after being attacked and heavily damaged by dive bombers at position 196,95.
Merchant convoys scattered to the four winds as the enemy threat revealed itself. One particular fortunate convoy was a fuel laden 4 tanker convoy heading to Pearl Harbour that was immediately recalled to San Francisco when the revealed Japanese ships were seen to be uncomfortably close to their position! A very daring move by the IJN and a combination of luck, bad weather and cryptic analyst brilliance saved the USN from a minor disaster.