A boat is provided with a steering arrangement comprising a main steering system and control-surface subsystem. The control-surface subsystem comprises a control-surface assembly attached to the stern of the boat and comprising a trim tab pivotally connected to the stern of the boat, and a skeg rotatably mounted by the trim tab. The control-surface assembly further comprises a trim-tab operating arrangement for pivoting the trim tab, and a skeg operating arrangement. The main steering system and the skeg operating arrangement can be selectively set to operate independently of each other, or in coordination with each other, in steering the boat.