The American cruisers carried SG and SK radar with Mark 34 fire control for the main guns and Mark 37 systems for the secondary batteries. At about 01:30, an American air attack lightly damaged Haguro, although the weapon remains uncertain between a bomb and a torpedo. Her reduced speed disrupted a formation whose groups did not all slow together. American radar contact at 02:27 allowed Merrill to send Burke against the northern screen and Austin against the southern screen, while the cruisers turned to use their six-inch guns at range. The first torpedo salvos missed on both sides. Uneven speeds and the attacks left the Japanese groups separated before American cruiser fire jammed Sendai's rudder.
Chapter · 1:50:45-1:58:48
Radar contact and the opening torpedo attacks
Merrill used radar contact to divide his destroyers against both Japanese flanks while keeping the Cleveland-class cruisers outside the expected torpedo envelope.