A little structgural fiberglass repair

Livia and Carol on s/v Estrellita have been poking around down in their bilge. 

We took a lot of time in San Francisco to work on boat projects because we were enjoying the town, had a lot of free places to stay, and resources through friends in the area. This is one of the projects we tackled.

We’re now certain that our gorgeous girl has been grounded hard at some point. There was the rudder shoe repair, the old bad keel repair that failed that we re-did and now we found a crack in the fiberglass in the stringer (I think technically called a “floor”) behind the mast step.

Our concern of course, was whether the crack was in the fiberglass or the underlying beam. We could tell the crack was old because of the mold (ew!). So we dug, and scraped, and ground, until we found dry, uncracked wood (phew!). Then we considered how best to deal with the big hole we had created.


West Systems has a great series of videos, articles, and use guides for using their epoxy resin to repair fiberglass. We used epoxy resin and glass cloth. This was our first experience actually doing our own fiberglass repair so we decided to tag team it “Team Giddyup” style. Carol ground and beveled and I applied the glass. We chose epoxy resin for its strength but an unintended side effect is that it smelled WAY better than the fiberglass resin that they guy who did the keel repair used. We are very thankful for that because we weren’t looking forward to getting a hotel while the stink cleared out.

So, while enjoying the hospitality at the Oakland Yacht Club, we applied about 10 layers of glass cloth with epoxy resin. Can you believe that this still did not build it up to the same thickness that the Wauquiez builders had left? It’s *crazy*. Part of that is because we had scraped some rotten wood from the surface and part because we underestimated how thick the layer would need to be in order to match the existing glass.

Of course, our boat was build back in the days when they had no idea how strong fiberglass was so they just kept adding more to make sure the boats would be strong enough.

We’ll watch the repair job and see how it does over time. Luckily, these stringers/floors simply stiffen the boat laterally and so, unless you ground the boat, don’t normally take a lot of fore-aft stress.

We also found old repair jobs in the corners of other stringers on the starboard side. Hopefully, those repair jobs, which were smaller, won’t fail like this one did.