Exposing the Stern Damage

In my second work session on the Probe 12 canoe, I removed the knee pads and the stern deck and ground a lot of the Kevlar/epoxy patching from the sterns interior and exterior.

After doing a bit more grinding and examining the extensive cracks in the hull bottom between the knee pads, and noticing its thinness, I determined that I'd have to place a fairly large sheet of kevlar over the area to beef it up. In order to make room for that, I removed the knee pads, using a heat gun and putty knife. They came up without much trouble, then I ground the surface fairly clean and smooth.

Next, I removed the stern deck. This was attached with three stainless bolts and nuts (front/center, and both ends) and a bunch of aluminum pop rivets, which I drilled out. This gave me access to the inside stern. I used a small angle grinder to remove virtually all the kevlar, which was laid into the hull poorly, with many bubbles and gaps. It may have provided structural strength in the stern, but it was doing nothing to keep the water out. It came out easily, but it exposed some large cracks in the Royalex. 

Another view of the stern, after the kevlar was removed.

Then I went to work grinding down the kevlar on the outside of the stern. This was more problematic. Large areas were poorly-adhered, while others were epoxied solidly to the Royalex. I ground out everything that was at all loose. This exposed the black-and-yellow striated area where plastic welding had been done at some time in the past. 

The other (port) side of the stern after grinding. The striations had not been filled with filled epoxy, so the kevlar just sat on top of the striations and was not well-adhered. Everything that was loose was ground off, while some of the surrounding kevlar, although lumpy, was well-adhered. Removing it in order to create a smoother surface would probably create more damage than it would remove, so I smoothed out some of the bigger bumps but did not attempted to remove it. I also ground off most of the bigger epoxy drips.

Close-up of the stern, with a light shining from underneath, shows the extensive cracking and the extreme thinness of the remaining Royalex. This will be the most difficult part of the repair, requiring a lot of filling and fairing to make watertight, strong and smooth.