O'Day Daysailer 17 Hull Repair | December 2006 - January 2007

Last winter, a tree fell on this boat when it was stored at the owner's camp.  The tree broke the mast that had been stored on the boat, but the force of the falling tree also forced the hull down onto the trailer bunks, which created a short fracture on the port side of the hull aft, and also a fracture inside the cockpit molding on the starboard side.

After the owner delivered the boat to the shop, I began with a careful inspection of the damage, as well as the surrounding hull.  I noted a series of stress cracks in the hull radiating from the trailer bunks, apparently a result of the same impact from the tree, but they didn't seem to overly compromise the hull's integrity.  Once I prepared a repair estimate and received the authorization to proceed, I moved the boat inside and prepared to get underway.

 


       

These photos show the cockpit (left) and hull (right) of the boat as she was when she arrived here.  The tree's impact shattered a portion of the deck/cockpit molding in the gutter on the starboard side, about 24" forward of the transom.  The hull crack was on the port side of the hull, about 12" from the centerline of the boat.
To begin, I first dewaxed and cleaned the two areas in question, and then ground back the hull on either side of the crack, tapering the sanded area back to gelcoat a few inches back. 

In the cockpit, I couldn't machine grind the area, as the gutter made the space too tight, so I hand-sanded the area as required.  I decided to simply span the entire shattered area with new fiberglass.
With the prep completed, I laminated new fiberglass in place, using epoxy resin and biaxial cloth.  On the hull, I installed two layers of biax, overlapping each other, to make up the required thickness of the repair; on the cockpit repair, I used only one layer, which was more than sufficient given the original construction.
When the fiberglass had cured overnight, I cleaned it and sanded to prepare for fairing.  Then, I troweled on a first coat of epoxy fairing compound.
After sanding the first coat, I troweled on a second coat of finer fairing material in the cockpit to fill some pinholes and low areas.  On the hull, a second coat turned out to be unncessary.  When this material cured, I sanded both areas smooth and fair with the surrounding hull and cockpit, adn then sealed the fairing compound with epoxy resin.
When the resin overcoat had cured, I sanded both areas smooth with 220 grit paper, and prepared to gelcoat both areas.  With proper mechanical preparation and technique, polyester gelcoat can be succcessfully used over epoxy-based repairs.  I followed the guidelines precisely, and sanded the repairs and a wider surrounding area with up to 320 grit paper.
I prepared a batch of color-matched gelcoat, refraining from mixing in the catalyst until I had mixed the color properly.  Since curing tends to change the color of gelcoat somewhat, I dabbed small bits of the mix on the repair area to allow the basic solvents in the uncatalyzed gelcoat to flash off, closely replicating its cured color.  From right to left in this photo can be seen the 5 stages of the color adjustment required, as I added only tiny amounts of coloration to the white base gelcoat with each addition.
Once I was satisfied with the color mix, I catalyzed the gelcoat, thinned it for spraying, and applied several coats to the repair using a small sprayer.  I started with the actual repaired area, and slowly widened the sprayed area with each coat, gradually tapering and blending the gelcoat with the surrounding areas.  When I had applied sufficient thickness, I oversprayed the repairs with PVA, since gelcoat won't fully cure in the presence of air.  The PVA forms a light film and isolates the surface beneath from air.
Once the repair was fully cured, I washed off the PVA with water, and then wetsanded the repairs with 320, 400, 600, 1000, and 2000 grit sandpaper, carefully blending the seam in with the surrounding original gelcoat and removing the orange peel from the spray application.  Then, I buffed out the repairs using a 3-stage process.  The newly repaired areas were virtually indistinguishable from the surrounding, aged gelcoat.