Testimonials
Epoxy, built 1966
Sheer Strake
Wow! I did not even know where to start with this. One solution I was definitely thinking about was to just replace the whole rail. However, that would mean even more work and a bigger budget. Since the rot was isolated to this area, restoration was still the best answer. There are many different ways to repair this. Since I wanted to test the products and experiment with different application techniques, the following are the steps that I followed.
On your immediate right, Fig 2, is a view of the above picture but you are now looking down. When I purchased the boat I had no idea this was even a problem, It was hidden under a fresh coat of paint! A close examination of the paint revealed some suspicious bubbles. A screwdriver revealed that rot had taken hold here and the damage was very extensive. A previous repair consisted of using a longer screw with the hope that there must be some solid wood somewhere underneath the decking. By the time I found this problem there was nothing left to work with. The Plan was to saturate the area with Clear Penetrating Epoxy Sealer, and then fill the void with Layup and Laminating resin mixed with sawdust.
This is a close-up, Fig 3, of what the plywood looked like after heavy saturation with CPES. You can see the screw and how most of the wood it was holding is gone. This particular joint is where the top lap stake or sheer strake was screwed to the decking.
I would like to say that a lot of skill was involved in this part of the repair but it was pretty basic. I used a thick mixture of Layup and Laminating Epoxy Resin mixed with sawdust. The initial application was made very thick as I did not want it to flow for the beginning of this repair but just to stay put when pressure from clamps drew the rub rail to the decking. Figures 4 & 5 indicated there was very little material to glue or screw into. After this cured in a couple of days, and the rub rail was in the correct position, a thin mixture was poured and smeared into the area. My thoughts behind this was very simple, any voids would be filled with the epoxy thus returning strength and now I would have some material that could be screwed or glued. This was repeated several times till all the missing wood was replaced with epoxy resin and sawdust. I had to admit that it does not look good at this point and some of the guys at the boat yard let me know their thoughts about this repair. I was not concerned because the major problem had been eliminated, that being the rotting process itself. At this point it does look rough but it turns out just as I expected. I do realize that this is not the same as replacement with new wood but in the end you will agree that my solution was the next best thing considering it was a fraction of what wood replacement would be.
What we see in Figures 6 & 7 is the building up and sanding process that took place to make sure there were no voids in the resin mixture. A lot of experimentation took place as to mixing ratios of sawdust and resin. The different colours and materials seen in the right picture are old mixtures of fiberglass from previous repairs along with our two part Fill-It Epoxy filler. From the outside things seem to be taking shape. You can compare the Fig 6 to the previous Figures 4 & 5. I used a very thick mixture to replace the missing section of wood in the rub rail. What is it like on the inside? We will see this at a later date.
Fig 8: This is what the repair will look like till I am ready to fair and paint the whole hull. I have decided to strip all the paint from the hull down to bare wood and apply Clear Penetrating Epoxy Sealer to the whole hull. Too many sub-standard repairs have been discovered where the rot infestation was not halted. Rot has taken hold very well in some areas below old repairs and that only results in a temporary repair that gets worse over time. I did a quick calculation and I will be putting in almost eight hundred new fasteners due to minor rot between the lapstrake planks and about seven gallons of CPES.
After completing the rub rail repair, I became concerned about the condition of all the decking where it joins the rub rail. I began drilling 3/8 holes every few inches to evaluate it's condition. All in all things were not too bad. 70% was solid with 30% in fair to bad condition. I drilled the holes approx four inches apart and then inserted clear tubing. I filled these tubes up with CPES and let it slowly soaked into the wood. This was done for a couple of hours. Epoxy's main deck is constructed of Mahogany plywood with teak in-lay on the top to simulate decking. This is why rot takes hold in these places so easily. Plywood’s end grain is very susceptible to water absorption due to the nature of its construction.
View plywood prenetration tests here
After I saturated the wood with as much Clear Penetrating Epoxy Sealer as possible, it was now necessary to fill the holes and return some strength to the area as a lot of holes were drilled. Some areas were pretty rotten so this also validated the next step. 3/8 wooden dowels were saturated with Clear Penetrating Epoxy Sealer and then let dry for about 12 hours. This meant that most of the solvents had dissipated, however the resin was still curing. I then poured the mixture (sawdust and laminating resin) into the holes and drove the dowels home with a hammer.
When the mixture cures, it will all be bonded together and some structural strength will return. I will also have to saturate this area from the inside as well in order to prevent and to eliminate the rot from spreading. Fig 14 are the dowels soaking in the CPES and the lower picture is an area with the dowels installed. I received a lot of questions in the boat yard about this as it is definitely a different way to approach a repair of this nature. I also received a lot of criticism from traditionalist, however the repair is not yet complete so I will reserve judgement till it is finished completely.
Fig 15 is another photo of the rot in the rub rail. This extended about (5-8 cm) right through the rub rail into the decking. I used a screw driver to dig out as much of the rotten material as possible. I am discovering that this is a necessary step as indicated in the six steps to restoration. CPES cannot make rotten crud into solid wood. It is however extremely effective at halting minor rot (rotten crud must be removed so some mildly rotten wood is revealed). CPES will then penetrate through the rot into solid wood and bind the fibers back together. I used a rinse bottle (see accessories) as it was the perfect for spraying the CPES into tight corners and cavities that you cannot get to with a brush.
Figures 15 & 16 are before and after the repair. In Fig 15, the rotten crud is removed and in Fig 16, it is replaced with sawdust mixed with Layup and Laminating Epoxy Resin and sawdust. All that remains is to sand and apply Fill-It wood filler to contour the finish and match the existing line of the hull.
Fig 18: This is the completion of that repair. The next step will be the complete saturation of the wood on the inside with CPES. This will further stabilize the wood from expansion and contracting plus it will also prevent the spread of rot in areas that I could not access from outside.