Originally Posted by Drip

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.

oooh I see

all right cool thanks man