the apache 24 is pretty small, right?

What about a gear drive? I've heard that they are more efficient, but i'm not sure that one would fit in the apache.

I have two gp3300 6 cell sideXside packs that i would like to use in the boat to gain more speed, but i don't think they would fit.
Is there any way they could fit in the sponsons. Also, what esc should i use?