After what might have been too much forethought, research and opinion gathering we finally had the materials, tools, ideas and time to tackle the leaking port side deck core that has plagued our boat since about the time of hurricane Sandy.
While I have tinkered with West Systems epoxy since I was in my 20’s, this would be a rather large project for me to undertake. As a warm up for what was to come I decided to make up some backing plates for when the stanchion would be re-bolted through the deck. I made up a mold from scrap wood in Matt’s garage and used a few pieces of broken laminate from destroyed boats I had found after hurricane Sandy. I sprayed the flashing with a mold release agent and duck or duct tape helped seal the seams. The reddish tint of one of the backing plates resulted from using an old can of hardener while the clear one used hardener only from a new can.
These backing plates will come up again later.
The first step was to cut the upper skin of the deck and attempt to peel it back without breaking it.
The upper skin came up easily in some spots and not so easily in others. What we discovered once the outer skin was peeled up was that the Balsa core was unevenly rotted throughout the area: the worst rot occurred at the lowest spot of the deck near the toe rail but some sections were completely rotted to the edge of the dog house roof. The following picture shows where we found some stubborn bits of Balsa core.
To add to my misery the primitive tools we were using (hammer & chisels) helped to remove a few sections of the inner skin that was already compromised. The whitish section near the boat fender shows where the lower skin was removed and wax paper was propped up by plywood and dead men inside the cabin waiting for me to re-pour the inner skin.
Seeing all this rotted Balsa core I became more worried that the core near the chain plates was rotten so I extended the recore project just forward of the chain plates. I was somewhat relieved to find that either a solid piece of wood or ply was used for a core material in this area. It was not bone dry but it was pretty solid. This photo shows how far forward we went with cutting the outer skin.
Upon reflection I will say that we were missing one crucial tool that would have been quite useful: a router with a 1/2″ vertical cut with a bearing on the end. With a tool like this I could have removed the last stubborn bits of Balsa core which would have made putting in new core quite a bit easier. Since we were using the polypropylene honeycomb core material that my new friend Howard Crisp recommended we could use a sharp razor to cut out the more interesting shapes that were needed to fill the voids we had created. This picture shows the odd shapes of pieces of new core we added.
The polypropylene honeycomb core is great stuff and I highly recommend it as it costs about the same as a good plywood. Its only short coming that I can fathom is that, like Balsa, it should be drilled and filled with epoxy where any penetrations go through the deck. This would be the case where the offending stanchion base once stood. Instead of drilling and epoxy filling I decided to use one of my pre-made backing plates for core under the stanchion base. You can see me contemplating the idea in this photo.
By using a solid core in this area there was no need for drilling and filling prior to installing the stanchion base. The other backing plate was used inside the cabin to support the same stanchion base.
I wish I had more pictures of how it went gluing the old skin back on but it was already day 3 for me of working on this project and the sun was starting to get low towards the horizon in the west so I just worked instead of documented. I mixed up the biggest batch of epoxy I ever have in my life for putting the skin back on. It turned out to be a little shy of what I needed so I had to spend more time on day 4 of this project filling the seams with thickened epoxy to cover and seal the whole mess. Unfortunately day 4 happened about a week later and some rain had already found its way into the cracks. About an hours worth of judicious use of a heat gun seemed to dry things out enough for me to proceed.
As of this point I can say that it did not result in a picture perfect job and I still have a bunch of work still to do sanding fair and leveling some of the seams before I even get to repainting with non-skid paint. What I can tell you is that the deck now seems solid, does not leak and the boat still sails well with her clean bottom and propeller.