KanColle Kai talk:FAQ/@comment-114.121.157.173-20160327135614/@comment-201.215.125.139-20160329200145

I repelled a counter attack with 3 fleets, you need to have more than 2 fleets to use the 2nd and 4th slot.

I had my "firepower" fleet in the first and third slot (2BB,2CA,2CV) and a "torpedo" fleet in my second slot (2CA,1CL,3DD) and they act like a support attack for the main fleet, once my opening aerial attack ended, they attacked with torpedoes.

I'm not sure if you need a "torpedo" fleet as a secondary but I had the same "torpedo" fleet with my "firepower" fleet in another red hex and I couldn't set it in the second slot, only in the third.

So if you want to use the four slots you need four fleets in the same hex.