What is the purpose of the peel ply?

chris asked me to blog on that topic. we nomally use the peel ply when glassing so i have been thinking about the reasons. First of all, we will be less sading after peel it off unless there is peel ply wrinkle. The other reason why we use the peel ply is that it's holding the shape of the hull because once it's laminating, it would be very tight. Third, it will protect laminted parts from dirt,dusty and any other things because they might be exposed many days, also there are red lines so we can see that it's peel ply which means we can look after laminated parts.