EPOs: Should Drill Holes be Sealed

Last week I busted an EPO rudder when I was rushing to take the boat down in the pooring rain. I have a new white EPO2 polyester rudder that I am ready to drill holes into. Can anyone tell me if the foam core needs to be sealed where the holes are drilled? What do you use?

Nope. Never heard of an issue. The area the holes are drilled is also solid / thicker glass.