User blog comment:Shinhwalee/Guide to Power Leveling Heavy Cruiser (CA) in World 3-2A/@comment-84.90.161.45-20150712213842

You only need to rotate the SS when it gets taiha'd, to avoid it sinking in the next run.

I find that Goya, Iku and Hacchan are not so good for rotation, due to their higher HP and consequent longer repair time. A lvl 10 Goya with 1 HP can take up to 15 minutes of dock time to fully repair. Imuya and Maruyu are better options (Maruyu is the best tank). My lvl 22 Maruyus only take 8 minutes of dock time to fully repair.