Step 9:
The speeds of these hulls are increasing

That's why I decided to laminate the complete hull. My experience is that in time the thin plywood will otherwise crack.
After I laminated all surfaces with glass cloth, I applied another layer of epoxy on the hull with a filt roller. It works great! The epoxy fills the glass cloth structure and makes the hull skin nice and smooth again.
I suspended the hull on the transom, so I can epoxy the complete hull at once.
Finally I wet sanded the hull. I am happy with the result, the glass cloth cannot be seen anymore.
I am now working on the strakes. After that I can apply the paint on the hull. Only the temperature should rise, because it's still freezing cold here!