One subject that strikes fear into the heart of most boat owners is the term "hull blisters" also knows as "boat pox". Whitby's have little or no history of such a problem but it pays to take precautions. Painting on a barrier coat before applying anti-fouling is one such option. The fact that the hull had been dried for such a long time made this an ideal opportunity to do this.
First the old anti-fouling had to come off. Wet sandblasting is a good way to do this as long as the operator know what he is doing and avoids damaging the underlying gel coat. It all worked extremely well.