Answer:
I have a lot to say but can't be heard because I can't speak one single word. What am I?
Face with a tree skin like the sea. A great beast I am. Yet vermin frightens me.
Without a bridle or a saddle across a thing I ride a-straddle. And those I ride by help of me though almost blind are made to see.
If you drop me I'm sure to crack but give me a smile and I'll always smile back. What am I?
I am heavy forward but backward I'm not.
Black we are and much admired. Many seek us if they are tired. We tire the horse, and comfort man, and turn White when we've fulfilled your plan.