Intended for the deployment of large mechanical units such as the Bringer of Thunder, Whirlwind, and similar designs, large mechanical unit launch bays use a variety of systems to effectively prepare to launch, and launch, large mechanical units from a given ship or installation. Like typical launch bays, electromagnetic catapults are used for the purpose of propelling the machines from the launch bay, however, these catapults also include a sled in which a given machine is to stand or kneel upon during the launching procedure. These launch bays incorporate a series of magnetic servo and mechanical driven bay doors, and exterior and interior defenses which vary by application. Launch bay doors include forcefield systems to prevent atmosphere leakage in the event of bay door malfunction.