Blue and White Ceramic Clock

This is a ceramic clock with blue and white painted decoration of boats and flowers. It's signed "Van Prenn" at the lower front corner, and appears to have the word "Delft" painted on lower back corner. There are some spots on pink tint here and there. I can't tell if they're the color of the ceramic showing through or if the color is in the glaze. The bottom is not covered in the same glaze as the rest of the body, and has indistinct markings incised.