Upon viewing this pic again, I can't help but think, one catapult for launching kanmusu doesn't seem to be enough
Depends on how quickly it can be reloaded and how many it's expected to launch. If it can spit out one shipgirl a minute and isn't supposed to be used for more than six girls, it's fine. If it takes 5 or 10 minutes to reload, and/or you want to launch a fleet of 30+ girls, then, yeah, not really sufficient.