The RBU-1200 (Russian: Реактивно-Бомбовая Установка, Reaktivno-Bombovaja Ustanovka; reaction engine-bomb installation & Смерч; waterspout) is a anti-submarine rocket launcher.
The weapon system is remotely similar to the British Hedgehog anti submarine mortar launcher from the Second World War.
The launcher cannot be swiveled horizontally, but rather has to be aimed by turning the entire warship, which is a serious disadvantage of the weapon system and limits its flexibility.
The projectile is propelled by a solid rocket fuel motor initially, and for the rest of the flight it follows a ballistic arc.
K-3 / K-3M fuze detonates the warhead if a target is hit directly or if the projectile sinks to the bottom.