The dull gray band about the width of the key is evidence this shaft has been lapped to its propeller.
A propeller shaft has a tapered end that should exactly match the taper in the propeller bore. Any time you get a new shaft or propeller, you need the “lap” the two to get a tight fit between them. This fit is essential to minimize vibration and ensure the best transfer of power from the engine to the prop. Lapping is accomplished with lapping compound (Of course it is, right?). Lapping compound is just a finely regulated gritty substance that machinists use to make metal joints fit–like intake and exhaust valves in engines, or propellers on shafts. There’s no magic to it. Just slather the stuff on the taper of the shaft, and then rotate the prop around the shaft in a back and forth motion. Do this until you get a good, evenly dulled surface all around the shaft and inside the prop bore. If you’re unsure where the high spots are, you can paint a blue chemical dye called DYKEM on the shaft. Then scrub the prop back and forth and see where the dye transfers. Continue reading “Lapping the Prop to the Shaft”
The evil staple rot again! We’ve got to fix this before our new upholstery staples will hold in the edge of the dashboard.
We’ve referred to the evils of steel staples and the rot they produce in wood over time in a previous post here. Well, that staple rot exists in the top of the dashboard too, since the crash pad was stapled to it as well. We can either rebuild the dashboard, or restore it. In this case, cutting out the offending strip, and gluing in a “Dutchman” will fit the bill. Continue reading “Fixing the Dash”
How to make a large hole larger? Don’t run for your rasp or round file.
The engine compartment ventilation holes needed enlarging. For whatever reason, they were seriously undersized according to the plans, and my calculations of what is necessary for that size space.
So, if you already have a hole in the boat, how do you make it bigger? How do you get your hole saw, or your drill bit to center itself on the hole, when there’s nothing there for the pilot bit to bite into? Continue reading “How Do You Enlarge a Hole?”
New ceiling planks have to be fitted, then taken back out of the boat for staining and finishing.
Boat vocabulary can be crazy and frustrating. For example, what do you call the planks that line the inside of the cockpit, and give it that beautiful, rich look? Why the ceiling planks, of course. And you thought that word meant an overhead surface, didn’t you?
New ceiling, port and starboard.
Oh well, I didn’t really like the look of the old ceiling planks I took out. And it was a simple matter to use the old ones as patterns and make new. Actually it was easier to make new than to strip and refinish the old ones. Not to mention the risk that one of the old, brittle planks might break when putting them back in.
How to hold the pieces in place while you fit them requires some creative solutions.
The challenge was how to clamp the new planks in when fitting them. That is often the case. Boatbuilders as a group are some of the most creative clampers I know.
With the major project of fixing the staple rot out of the way (see earlier post here), it’s time to start re-assembling the interior of the boat. Some of the old parts could be re-used, but many had to be made anew. New fuel tank saddles, engine beds, seat supports, etc., etc. If there was a doubt about whether new part would last another 60 years, it was re-made. The picture above is just a fraction of the parts that had to be made, painted and assembled to get this baby back in the water.
The steel staples used to hold the upholstery around the edge of the cockpit have rotted the planking around the perimeter.
Anytime you have ferrous metal and water, you’re going to get oxidation. This oxidation causes rot in wood. In our case, the ferrous metal is the staples used to hold the upholstered “crash pad” around the perimeter of the cockpit. In the picture above you can see that the planking around the edge of the cockpit has turned black and is crumbling.
You can see the upholstered crash pad in this early post before I disassembled the boat.
Closeup of the evil staple rot
There’s no way that it would hold new staples for the new upholstery we’ll order soon. Take a look at the detail picture here. So how do you go about fixing something like this? Cut out the bad and put back new! It’s really that simple. But it’s a rather involved process. I decided to make a template of the cockpit opening, and using a template guide for my trim router, I was able to cut away the rotten wood so that I had good wood to glue new pieces to. Continue reading “Fixing Cockpit Staple Rot”
Fiberglass cloth draped over the bottom before initial trimming.
A layer of fiberglass on the bottom serves two purposes. First, it provides a tough protective layer for rough treatment on a trailer or accidental grounding. Second, it holds a nice, thick epoxy layer that makes the bottom more water proof. Nothing is really water PROOF. But epoxy is pretty close. It takes a long time for water to migrate through unbroken epoxy.
It only takes a few days to add this beneficial protective layer, and now is the time!
We used 6 oz. 0-90 bi-axial woven roving. Let’s break this down. Six ounce means the fiberglass cloth weighs 6 ounces per square yard. 0-90 bi-axial means the threads in the cloth intersect at a 90 degree angle. Woven roving means the fabric has a simple over-and under weave to it. This cloth drapes well and will conform to the shape of our bottom.
Rough-cut fiberglass cloth is wet-out with epoxy.
When you apply fiberglass to anything, it’s held there with some form of resin. In our case, we use epoxy. If you do a good job, the resin fills the weave and displaces the air, making the cloth essentially invisible. It’s really cool how this works.
Trim the edges with a sharp knife while the epoxy is still green.
While the epoxy is still “green” (partially, but not fully, cured), it’s time to trim the edges of the cloth with a sharp knife.
Fiberglass applied.
After the first coat of epoxy cures, we can 2-3 more coats to fill the weave and the cloth will disappear completely.
Famowood putty is used below the paint line. Wood bungs are used above the paint line.
We still have over 1000 screw holes in the bottom that need to be filled somehow. We’ll use two methods, depending on whether the screw hole will eventually be under paint or varnish.
Over 1000 screw holes to fill and sand smooth. Good thing our putty is quick-drying!
I use a wood filler called Famowood for any screw holes that will be under paint. It’s pretty waterproof, dries quickly, sands easily, and won’t shrink. It’s been around for years and is superior to most other wood filler putties you can get at the big box stores.
For those screw holes that will be under varnish, the traditional approach is to fill the hole with a bung cut of the same wood, glued in with varnish or some other fairly un-tenacious glue so that the bung and screw can be removed later if repairs are necessary. Boats do run into things occasionally, and it’s best to be kind to the poor person who may have to replace a plank later on.
Epoxy looks like varnish, but it’s a lot tougher and more waterproof.
After all holes are filled and sanded smooth, we’ll add a coat of clear epoxy as a sealer and to provide something for our fairing filler to adhere to. Then we trowel on the WEST System 410 fairing filler to the low spots. Let it cure and sand it smooth.
Fairing filler is used to fill low spots. It’s unsightly, but it’s going to be under paint.
At the risk of getting ahead of myself in terms of blog entries, we flipped the boat this past Saturday. This entry is a little out of sequence, but I’m too excited to wait and post it in order. I’ll catch up on the other steps for finishing the bottom later.
Once the bottom is finished, barrier coated, and painted, it’s time to flip the boat over and continue with it in the upright position. You can see in the picture above the apparatus we use to flip a boat. It’s a 1-1/2 inch pipe suspended above the boat in a couple of purpose-built bearings. I use 4 inch load straps over the pipe, which turns in the bearings, and allows us to roll the boat.
Click on the link below to see a short video of the flipping of the boat.
You can see where the planks alongside the keel have been ground down smooth with the keel.
Now that all the planks are glued on to the bottom, it’s time to go boating, right? Not quite. There’s still a lot of work to do. We have to “fair” the bottom. That is to say, we need to make it smooth, with no abrupt dips or rises. It needs to be “sea-kindly” so that the surface addresses the water with as little resistance and turbulence as possible. We’ve just glued a set of flat planks onto a curved bottom. It stands to reason there’s going to be some sculpting to get them to follow the curves of the bottom smoothly.
This is best accomplished by the judicious use of a 6″ Festool DA (dual action) rotary sander/grinder with a soft pad. This tool will move some material. So take it slow. Don’t be afraid to stop and feel often. You can see what is fair after you’ve trained you’re eye. But your fingers can feel “fair” with no training at all. Trust them and take it slow.
In addition to grinding down some of the sharp edges, we can also fill low spots with epoxy fairing filler. We’ll apply the filler a little later, but it helps to bear in mind that filling is an option, in addition to grinding down. I use WEST System 410 fairing filler for this job. It’s easy to apply to the low spots, and it sands easily once it has cured.
The outer chine is glued on just a little bit proud of the bottom so it can be trimmed flush later.
Then, it’s a pretty straightforward job to glue the outer chine on. We’ve already defined our line and fit the outer chine, so it’s time to put it in place permanently. Just make sure there’s plenty of glue so you get good squeeze-out. This is definitely a place where you don’t want voids that can trap water and promote rot.
Plenty of glue ensures we won’t have voids that can trap water in the joint.
Trimming the outer chine flush to the bottom with a low-angle block plane
Then we have to trim the top of the outer chine (actually the bottom, but since we’re upside down, I’ll call it the top) flush with the bottom planking. This is easily accomplished with a low angle block plane held to the face of the bottom planking.
