It does look good, but I have to agree, a few splashes would add even more Karl. Try putting it an upended box, mix up a batch of quite light coloured pigment and flick this, with the aid of a long bristled brush around the rear of the hull. When it's dry, go over it with some darker coloured pigment, but leave areas of the lighter colour showing through at the top. It should as if some of the 'highest' mud is beginning to dry.
Vinnie