One of Marineville's main defences are her deadly underwater interceptors, which guard the base's ocean approach. The interceptors are powered by magno-dyn atomic engines, which achieve a water speed of more than 150 knots. Hostile craft within a range of 12 miles of Marineville stand little chance.
The underwater interceptors are launched from giant compressed-air-operated catapults. A jet of air sends the missile from the ocean floor to the top of the water where the boosted motors ignite and carry it on its journey. Conveyor tracks are used to carry the interceptors from the storage arsenal to the catapult.