Filling small holes in hollow grp rudder. Advice please.

[Poignard]

I drilled a few 6mm holes into a hollow grp rudder to allow some water to drain out.

These holes now have to be filled in [I intend to use thickened epoxy for this] but, as there is only access from outside, how should I support the thickened epoxy while it sets?

 

[savageseadog]

Just tape over I'd say

 

[PuffTheMagicDragon]

I have always pushed in a short wooden dowel and then smoothed over with epoxy putty. This makes it easier to pull them out and reopen the holes when, a few years later, the rudder needs to be drained once again.

 

[Danny Jo]

I would do it in too stages. Start with epoxy thickened with colloidal silica so that it stands in points like a pert meringue, pushed in with a spatula so that it is below the finished surface. Four hours or so later finish with epoxy thickened with a light fairing filler.

 

[Poignard]

Thanks for the advice above.

I wish I knew how it was getting in. I drained about 1/2 pint out of it but the seam between the 2 mouldings looks perfect and there are no cracks. It's a transom hung rudder and there is no steel tube through it. There are 3 pintles but the only one below the waterline is the one at the heel and there's no sign of any leakage there.