User blog comment:Shinhwalee/Guide to Power Leveling Heavy Cruiser (CA) in World 3-2A/@comment-122.111.94.168-20150712144355/@comment-85.76.174.240-20150712164432

not really since your sub is there only to tank the hits, if you don't want your sub to take so much dmg then you can rotate it, but its not necessary