Actually, the Oka rocket bomb while a suicide weapon, was extremely effective once launched. in the few cases where the Japanese were able to position the carrier aircraft and launch these they devastated the ships they attacked. For their time they were essentially the equivalent of a human guided SSM. The USN really had no means to stop them after launch. Their speed was too great for fire control resolutions by existing equipment, their size was small and, they were quite fast. They also had a large enough warhead that against virtually any target they were going to do crippling or near crippling damage to it.