Love the moody sky and the feeling of mixed waters/textures on the sea. Can't really make much sense of the pencil lines on the sea, but I suppose they were intended initially and later decided best ignored, which is OK as well.
I do also like small sketchbooks. They are handy for carrying when traveling and being smaller allow for quicker finishing off a sketch (which is essential during a hurried sightseeing with more people). I have a few Talens Art Creation pocket ones that work acceptably well for watercolor.
Any way, love the result.