When we bought our Mariner 36, the surveyor made it pretty clear that our decks were wet and needed work. Lori and I were pretty bummed to hear this and were ready to walk away from the purchase, but after spending the cash to take a day off, driving to Seattle, hauling the boat and hiring a surveyor, the least we could do was take her for a sea trial (we have a little rule about turning down a nice sail on a sunny day). This, alas, was our undoing. One pass across Lake Union, and we were sold. She sailed like a dream. Deck, shmeck…we decided to reduce our offer and walk away happy. The seller didn’t hesitate. hmmm…
We happily ignored the wet deck for the next 6 years, sailing and growing on a boat that also needed pretty much everything else fixed too. The deck, while wet, didn’t really feel spongy, and aside from constantly resealing the chainplates to stop leaks, it was fairly easy to pretend that it was fine. And then Jeff ( a very good, but overly observant friend) said “feels like you have a soft spot here”. Damn.
There are a few schools of thought on fixing decks, but in my humble opinion, all but two are nonsense. These two schools both require the removal and replacement of all of the wet core material; one through the top skin, and one up through the bottom. Any suggestion that a satisfactory long term repair can be done without removing the core is wishful thinking. Any rot in the deck will spread, maybe slowly, but surely as long as there is there is water in the core.
We tackled our decks both ways. Our first effort was the foredeck, and this we did from below because of the easy access. The job was unpleasant, but not overly difficult. First we cleared the boat in anticipation of the fibreglass dust that we’d create, and did what we could to contain the mess with plastic. I then removed the headliner and cut the deck open with a 1/4″ straight bit in a trimmer (a small router) attached to a shop vac to minimize the dust. While much of the core came out as a black paste, I was surprised by the amount of structurally viable but wet core I had to remove around the void to find dry core. In the end, the hole I created was about twice the size that I’d anticipated.
Next I cleaned the area up with a sander and 80 grit paper. This is required to get a good clean surface to bond the new material too. I cut new core material to fit the irregularly shaped hole I’d created, and rigged up a clamping mechanism before breaking out the epoxy. I borrowed an idea from guitar making to do the actual clamping: I cut many thin sticks of maple just a little longer than the space between the v-berth and the underside of the deck. These were to act as legs holding up my work; the extra length meant they had to be bent. The result is a nice dependable spring that will accommodate irregularities in the surface such as deck camber.
I did the layup in two stages – first I bedded the core in a thickened epoxy paste and clamped it overnight. Then I laid up the bottom skin with rovings, biaxial cloth and unthickened epoxy. I thought that doing the glasswork overhead would be a huge hassle, but it wasn’t. I was well covered with protective gear, and as long as the pieces were not too large they were easy to put on by myself. The biggest benefit of this approach is that as long as there is a headliner, there is no reason to try and make anything look good – the finish can be terrible as long as the quality of the layup is adequate.
Our next deck project was much more difficult. Our side decks, particularly the starboard deck, were rotten in significant portions. Due to the location of the cabinetry and the chainplates, doing the work from below would’ve been possible but very difficult. The big advantage would be that the deck would remain fair and the nonskid would be fine; going in from the top would destroy the non-skid, but the interior could stay in place, the space to work in would be less awkward, and gravity is an assist. I thought about this for a long while, and finally decided to go in from above and use Kiwi Grip to replace the missing non-skid.
This work was accomplished in essentially the same manner as the foredeck. The two big differences were that the edge of the top skin needed to be beveled to create a strong joint to the new glass, and the whole thing needed to be fair. Both were accomplished with the judicious use of a belt sander and angle grinder. Thankfully, my experience in the wood shop really paid here as it is actually quite difficult to create a large fair surface with a small belt sander. The other major challenge was weather, and in this we were ridiculously lucky to start the work at the beginning of one of the driest springs in Vancouver’s history.
This job was an incredibly intense process, and I would not tackle it again unless I really had too. Certainly, sound decks were a prerequisite as we searched for our new boat. Between Lori and I, we estimate that there are close to 500 hours in the job, including stripping the deck hardware, doing the deck work, painting everything, and finally re-bedding all of the deck hardware. Given my background, much of these are at a professional’s pace. None of it was easy work, as it is all in an awkward place given the shape of a boat. We are very happy with the results – the deck is solid, straight, and free of the crazing normally found on an old boat’s gel coat. In addition, we raised all of the stanchion bases off of the deck with solid glass spacers and removed the core everywhere a fitting penetrates; the new deck should be far better than the original. The real irony is that we’re selling her after enjoying the new decks for only 2 years. Word on the street is that I like projects; I’ll pass on doing another deck thank you.