Originally Posted by HungryHunter

Am I playing da wrong game

Nutaku I did do whale ship but it didn't restrict me ti slice gurls

It's not a restriction, it's an option. If more than half of the girls on your ship are of a specific type, then the ship becomes of that type, and effectively gets a 50% ATK bonus against bosses who are weak against that type.

So if half your crew is slash type girls, then the ship deals more damage against the bosses who are weak against slash.