All previous sealant was removed and chock area was thoroughly cleaned. The holes have been taped and are ready to be filled with Six10 thickened epoxy
Careful readers with good memories might remember that we had a leaking rail chock after our passage to Hawaii. We made two attempts to stop the leaks. First we pulled the screws and sealed them from the top. When that didn’t work, we removed the entire stainless fitting, added sealant to the bottomside of the fitting and the screw tops, and reinstalled.
Filling the holes with epoxy
Well, it turns out our second effort didn’t really work any better than the first. We still had a small amount of saltwater oozing into the boat from the fitting. Even though this leak only happened when the boat is heeled over far enough to submerge the rail, or when the boat is punching its way through waves in a good imitation of being under water, it’s still something that we need to fix since the leak is conveniently positioned above most of the electronics that help to run the boat.
The left side shows the new epoxy lined hole and right side is epoxy-filled and ready to be drilled
We’ve rebedded enough fittings over the years to have at least fair confidence in our sealing technique. So, after two failed attempts, we figured that the water must be finding its way in through some path besides the top of the screw holes.
Drilling a new epoxy lined screw hole
After pulling the chock out of the toerail again, out came the dental picks. A few minutes of poking and prodding later, we found some failed sealant between the bottom of the teak toerail and the top of the hull-deck joint. It seems likely that water was forcing its way past that failed sealant, running down the hull-deck joint, and then trickling down the chock screw. Since the sealant we added is on top of the toerail and on top of the chock, it had no effect on the leak.
Beveling the edges of the holes after drilling through the epoxy
It was clear that we needed a new approach – in addition to cleaning and reapplying the failed sealant, we also had to find some way to cut off the path for water that might make it past the sealant in the future. We decided to bond in new epoxy screw hole liners.
To do this, we drilled out the 3/8″ screw holes to 1/2″ diameter (the largest drill size we had). We then carefully cleaned and dried the holes and filled them with Six10 thickened epoxy, being careful to do lots of stirring to promote good adhesion to the fiberglass hull-deck joint and the wood toerail as well as to eliminate any air bubbles or voids in the epoxy.
Taping the chock prior to sealant application
After letting the epoxy cure, we carefully redrilled 3/8″ holes back through the 1/2″ diameter cylinders we just made. This left 1/16″ walls of thickened epoxy around each hole. In theory this should prevent any water that finds its way under the toerail from leaking into the screw holes in the future.
5 diapers taped to the underside of the chock in case the third time is not a charm…
The final step was to thoroughly clean and remove any trace of old sealant from the toerail area and the chock, and then rebed the entire chock. We used a tube of Dow Corning 795 silicone adhesive left over from our port frame project, and fingers crossed that the third time’s a charm!
