Rockets on PT boats were considered because the navy wanted a weapon that dealt with shallow water
craft like the German F-Lighter in the Mediterrean Sea and the barages that the Japanese used in the Solomons Islands.In the Pacific in 1944 it was tried out with a primitive launcher, and then improved launcher was developed and installed on PT-489 and PT-491 in the phippines in March,1945.
These saw combat against 3 luggers,1 floating and 2 beached with 16 rockets against them. Sinking 1 luggers and badly damaging the other 2.This occured in the Tarakan and Borneo area.