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Email This Page to a FriendPreview: Wooden Boat Repair — Refastening Part 1 — Scoping Out the Job
April 19, 2012
Every wooden boat owner knows that refastening is in their future; but where do you begin? John O’Donovan and Patrick Dole walk us through assessing the state of the fastenings of Bill Mayher’s Concordia 31 that’s five decades old. We learned a lot.
– We all know as wooden boat owners, refastening is in our future. This boat’s 47 years old, and I knew that was coming down the line, and of course I thought, first of all, about doing it myself. My nightmare was getting stuck half way in the thing, and getting a whole lot of screws that weren’t coming out anywhere near as easily enough, and getting into some sort of endless nightmare. So then the question was, if I’m not gonna do it, who’s gonna do it. And I guess I talked to a lot of people who knew, and they said that refastening is simple repetitive work that has to be done by very talented, experienced people, or you get problems.
– Bill came in the shop,
– And said, “I’ve got a Concordia 31 that I’m interested “in having refastened.” And one of my first questions to him, well there’s a number of different ways that you can refasten a boat. You can do what Bill was mentioning before, which is stick a screw right between the other two, and you can go that route. You can go the route of trying to stagger screws, one on each side of the existing ones at an angle into the frames. Both those methods, as Bill mentioned, kinda makes Swiss cheese out of the plank.
– And make it like a perforated line, so you know, the best method is to either pull the old screws and go one step up, or pull the old screws and put a rivet through if that’s something that’s feasible with the boat, and the interior and things like that.
– So, I kinda posed those questions to Bill, and he being knowledgeable and already had the answer. He already knew what he wanted to be doing.
– Well Bill had pulled some screws himself, which was good, so we were able to take a look at a screw in the shop, which gives us a really good idea of what we’re in for. We wanted to come down and look at just random locations and locations that Patrick and I know tend to be more problem areas. Places like the stem, and the rabbet, where the garboard meets the rabbet. Because you tend to get more moisture back there, places where the screws are gonna deteriorate a little faster.
– [John] If you’re pulling a few screws just to sort of get an idea of what state you’re screws and fastenings are in, it’s a good thing to make sure that you take some screws out in different places, because the life of a boat, people will go ahead and replace a few screws, but not replace all the screws. One of the good places to start is here at the stem, because you will run into some problems up here sometimes. And so it’s good to see what the state of the screw is. This is an example of a screw which the shank’s in pretty good shape, but the threads you can see, they’re starting to go right here, we’re starting to lose some of that grip there. And the heads in good shape, but it’s a good example of a fastener that probably, this is a good time to replace it. We come farther aft, we did pull a screw down here in the garboard, right at this rabbet seem, which is another important place. This is an area where a lot of times you’ll see people will replace a screw or two because they fell like things are getting a little soft down here. And as we did, we pulled this one and this is obvious to me that it’s a screw that’s gone up in size, as far as the fasteners in this boat go. It may originally been a little larger, sometimes you’ll see rabbet fasteners and plank to floor fasteners at a larger diameter. But this is a new screw. There isn’t a lot of deterioration on this screw, the head’s in perfect shape, and the threads are really nice. So this is something you might run into, if you just pulled or two, as you’d pull this screw out and say, wow, the boat looks fantastic, I don’t need to refasten, but it is important to take a few samples from some different areas. Top side screws are usually better than the bottom screws if they were all replaced at the same time. But getting around the boat a little bit and checking at the water line, checking the rabbet, and then a few random spots along the hull, it doesn’t take much longer than pulling one screw and it’ll make you feel much more confident in the job you’re getting into. So we just looked at a screw on the port side of the boat, and now we’ve come over to the starboard side. We’re in the same exact location, pretty much. And this is the screw that we pulled out over here. You can see that this screw needs replacement. The head has started to deteriorate, and the shank itself is starting to go. And the threads are pretty much gone. Someone has gone and replaced the screws in some locations, but not in all locations.
– So as you might be able to see here, there’s a ice-sheeting that they’ve put on at the water line, to protect this boat, cause it was gonna stay in the water over winter, and so the ice can obviously cut and chafe the hull, the plank right at the water line, so they put 1/8 inch polyethylene on the hull to protect it. One of the decisions that Bill had to make was whether we were gonna remove this, and refasten beneath it or not. And he decided to leave this on, and so that’s what you’re looking at when you see this area at the water line.
– So we have gone ahead and pulled a sample of screws. On Bill’s boat we’ve pulled about 25 screws out total, from different places along the bottom. And this is a good sample of what the screws looked like. So the majority of the boat we found the fasteners still had threads remaining in some fashion, and the heads still had slots that were fairly usable. And it was a perfect time to refasten, because that made these fasteners come out relatively quickly. And then we had probably 10% of the boat where the fasteners were deteriorated even further, and then a small section of the rabbet where the fasteners were pretty much completely gone. What we then did is we took a look at how many screws total, and what we thought were the percentages, and put a time for how long is it gonna take to get this screw out, how long is it gonna take to get this screw out, and that’s how we based our estimate. There’s no guarantee, you can take 25 and end up with a good majority looking like this, but if you do a good sampling you can get a good idea of what a screw’s gonna look like up near the water line, and what a screws gonna look like down in the rabbet.
– The other thing that factors into that time is putting the new ones in, and then bunging the holes, and then chipping the bungs, and you’ve go to think about all the way to the primer, and the bottom paint. What we didn’t have to do on this boat, cause Bill had already done it, was to scrape the bottom paint, and that takes some time too, so all those things need to be factored into a good estimate for refastening a bottom.
– And as far as figuring out what to multiply that time by, we basically will just count the number of frames, and how many screws per frame, and multiply that by two per side. Some boats, and different planks, you’ll have different numbers per plank. Some will have two fasteners, some will have three fasteners, and usually you can get a pretty good estimate because of course there’s different lengths, for each frame as you go up and down the boat, so we get pretty much a ball park figure on how many fasteners we’ll need, and get an estimated cost on what those fasteners are gonna go for.
– They came up with an estimate for the job. I think we all felt comfortable with that, that that was a real number we could go to work with that understanding in mind. They were pulling screws and going over the differences and the potential problems. I was not only studying the screws, but I was studying these guys and what they were bringing to the project, in terms of competence and confidence. They had ways, they had techniques. This thing was gonna work, and so for the first time, the nightmare of refastening looked like I could put that away forever with a reasonable cost, and a good ending.