Yesterday's attempt at fibre-glassing a new stiffening rib was unsuccessful due to a lack of adhesion so I removed it & installed the tip temporarily then drilled the required holes. I was then able to grind the original strengthening rib to a thickness of approximately 3mm using an angle grinder & abrasive flap disc, This left quite a bit of stiffness along the bottom edge so after cleaning up the shavings & touching up the interior primer I was able to cleco the rib in place ready for riveting.
