This RS200 had a run in with another 200 and came of the worse. Another boat T-boned the side with the spinnaker pole and punctured through the top sides leaving a ragged hole. The hole had ragged edges with a large crack extending outwards. The first step was to remove loose and damaged material. The crack was cut down the centre with a hacksaw blade to make the two halves sit flat with each other. The surrounding glass is sanded around an inch out to leave a chamfered edge to allow a scarf joint to be make in the outer skin of glass.
Once a clean flat hole had been produced, the process of repairing it could begin. To rebuild the sandwich, the inside skin had to be reconstructed. The inside of the hull was not accessible at this location, so to rebuild the inner skin some method is needed to hold a patch on the inside while the resin cures. The technique I used in this situation involves making a card template that coverers the hole and has an overlap of approximately 20mm around the hole. Next a small batten is made with a hole in the centre which allows a string to be connected. This batten is placed behind the card to pull it into position on the inside of the hull. I used old sail batten to do this. Once this is setup, the glass patch is laminated onto the card and a small amount of filler is spread around the edge. This helps the glass to bond to uneven surfaces. This is now inserted into the hull and then pulled tight onto the inside of the hull with the rope pull.
The next stage is to replace the foam core. On a curved surface a vacuum is necessary to hold the foam down while it sticks, however in this case on a flat panel just pushing the foam on will suffice. Once set, the foam is sanded flush with the surrounding foam, this leaves room for the outer glass layer later. Any gaps around the edge are filled with resin, glass bubble and silica mix.
The outer glass layer is applied next. This is best blended into the surround glass using a scarf joint. Onto this a glass patch is applied. This is now carefully sanded to a level just below the surrounding gel coat. To check this, use a straight edge placed across the repair to highlight high spots. The gel coat is repaired by spreading a new layer on, then sanding and polishing to a mirror finish.