The Chidori torpedo boats were not so much like American PT-boats but more like tiny destroyers. At the time of the incident, they were equipped with three 5-inch guns in fully enclosed turrets (1 single and 1 twin mount), as well as 4 torpedo tubes, with extra reloads (8 torpedoes in total).

That's 60% the firepower and 40% of the torpedo launchers (but 80% of the torpedoes themselves) that a Fletcher-class destroyer carries, at a quarter of the displacement. Destroyer-grade equipment indeed.