Sanding the hull is a never ending operation, because you can always find such part of the skin wich you need to sand more times. In addition to the hull hides some other non expected fault on the surface. Like when the two layers of the radius skin didn’t lay perfectly to each other and because of it didn’t adhere with the glue resin. Some pictures:

pic #1
pic #1
pic #1
pic #2
laminating failure
laminating failure
correcting failure
correcting failure