My first draft of this class quickly showed me the error of my ways, as the coordination of the multiple sub-sprites would be extremely difficult, due to scaling and flipping, for example. Especially scaling.
Unless.. the multiple subsprites were co-located - i.e. had the same position (which is a CENTRE position), even if this meant they had a lot of transparent content in them.
Once you do that, however, there's no longer any need for a composite class. You just mirror certain characteristics of the main sprite (position, scale etc.) on the subsprites, eliminating the need for a composite class.
Easier still, make the main sprite and the principal subsprite as a single sprite with all the necessary animations - say, the boat and its wake, and use a separate sub sprite for each of the other animations required.
So, long story short, no composite sprite class.