Waiting for Scarfs to set,
I started on the Rudder and Daggerboard
I think time management while waiting for epoxy to set will determine how long it takes to make this boat. With big long parts cluttering up the living room, and short sticky parts setting in the workshop/basement, I don't have anywhere to work unless I can convince my Sweety to let me epoxy in his living room! Not much of a chance of that!
Cutting out the pieces require a tight layout.
In order to fit all the pieces on the available plywood quite a tight cutting diagram is given. I made cardboard patterns and fit them on to best use the grain of the wood.
In order to get the cardboard patterns I transferred the plans to cardboard using dressmakers carbon paper, which is really a coloured wax paper, and a small wheel with points. The result is a dotted line pattern that can easily be cut out. I could have transferred directly to wood but I wanted to check the best alignment of wood grain. I just traced around the cardboard with a pencil when I was satisfied with the placement. I cut out my Skerry rudder pieces with a jig saw. I'm not a perfect worker so my lines are not always cut perfectly. I find jig saws difficult to move perfectly smoothly.
A couple of coats of epoxy on inside parts of the rudder. The paler coloured plywood is Russian ply. It is heavier than Mokume plywood and that was good for the rudder.
After sanding the inside pieces that form the channel for the rope that pulls up the rudder blade, I put a couple of coats of epoxy on all the inside faces. When the assembly gets glued up it's very hard to get to the inside. I also made the hole for the bolt that holds the rudder blade, and coated that with a couple coats of epoxy. I'm hoping to paint the blade but keep the cheeks bright. I'll decide that later though.
I had not ordered a sheet of 1/2 inch mokume ply. Instead I had some Russian ply that I thought I could use. It has no hollow parts and is quite high quality birch ply. I boiled a sample for a couple of hours. The wood eventually went soft but the glue held up perfectly. It's not very pretty, but I intend to paint this part anyway. It is also heavier and might actually work better. I also made the centreboard out of Baltic ply. I'm hoping that the extra weight will also work in my favour. Since both the rudder blade and the centreboard can easily be replaced I'm not too worried.
I made the hole for the pivot bolt and the hole for the rope to lower the blade. I sanded the area that will be between the cheeks so it moves easily. The plans did not indicate a position for the lowering hole but I don't think it is critical. I can always fill it and move it if I have to. Making the profile for the leading and trailing edges was fast and easy because the plywood creates a convenient series of parallel lines. I used my plane and coarse sandpaper.
Rudder detail, Russian ply proved to be very good and I would use it again with no hesitations. I have since made another hole on the opposite side to install a pull up string. See Below for details.
When I assembled the rudder, I placed very tiny finishing nails from the inside to hold the parts that create the channel for the rope. I did not want these parts to shift when I tightened the rudder sandwich during gluing. Everything eventually was in the right place and I clamped the rudder parts. I had quite a lot of squeeze out because I was worried and put more rather than not enough. When the epoxy had set but not hardened I gradually removed the squeezed out stuff that was still soft. When the whole thing had set properly I checked that the blade still fit in.
Part of the instruction were to place a rope in the channel while it was being glued up and remove it to mop out the squeezed out glue from the inside channel once everything was clamped up but not set yet.
The mokume plywood I had received was slightly warped and I was worried that this would harm the fit of the blade. It had made the fit very tight and so I put a couple of pieces of wood to widen the gap. That's what the green plastic and the paint stirrer are doing. I kept a few clamps on so I would not open up my joint. Once clamps came off I sanded the assembly and glued on the outer cheeks and sanded again. Had some trouble removing the tape I had placed to mask out squeezed out epoxy.
Dry assembly of modified rudder. I filed a groove in the rudder and cut a notch to allow the rope to freely pass through. I will place a cleat possibly in the front if it looks appropriate, otherwise on the back. I think it will be easier to access.
I had to sand the rudder so it would move freely, plus I put a small wedge in the rudder cheeks to counter a slight warp in the plywood. I hope it is not too tight and I can add a washer or shim to fine tune the amount of friction. The outer cheeks have been added. The whole assembly is nicer than I expected which will allow me to leave it unpainted if I choose. The blade part will be painted though. It is not nice enough to leave bright.
The bottom left shows the notch I cut, which corresponds to a groove in the rudder, to allow the rope to come up higher and be more accessible, I hope.
The centerboard is a 1/2 inch piece with handles at the top. The handles are being glued on here. Since I'm not stellar at cutting I will have to shape the handle to smooth it out. I cut the handles against a machined edge of the plywood so at least these are nice and straight.
I marked the area that needs to be shaped on the centreboard. The leading edge gets a 1 inch bullet shape grind and the trailing edge has a longer sharper profile shaped into it. This I will do with my plane and sander. It will be the same process as with the rudder blade.
The most efficient centerboard shape is a sort of bullet profile at the leading edge and a longer slope at the trailing edge. I ground these profiles and shaped the handle. It's ready for 3 coats of epoxy resin with sanding in between of course. The Blade is made of Russian ply and is heavier and stays down better than Mokume would have.
After 3 coats of epoxy the centreboard is ready for a final sanding and paint. The handle will be varnished and the board itself will be painted whatever colour I am putting on the hull. At this point I wish I had invisible paint because the hull is pretty rough! All I can see in my future are clouds of dust.
Needs sanding and it's ready for its first coat of paint.
After sanding all the rudder pieces I glued the arm to the main rudder box. The jig is to keep the arm at right angle. Once this is done I will make a larger cleaner fillet and start varnishing and painting the whole rudder assembly.
After sanding the rudder assembly gets a coat of primer where it is going to be painted. The daggerboard also gets a coat. I expect I will have to prime and sand a few times. It's fabulous material and sands really well. Epiphane product.
After sanding and recoating with primer and sanding again, the rudder assembly and the centreboard get a coat of paint. I figure I immortalized bugs, pollen and sawdust.
The Red arrow points to where I made another hole this time for the uphaul line for the rudder. The second photo shows the line in place. The third photo shows the 2 lines coming out of the top of the rudder cheeks. Each line come from a different side of the rudder blade and when I pull on the blue and while line the blade goes down, when I pull on the white line the blade comes up. It's easy to cleat whichever is supposed to be holding. Eventually I will brings these lines to the top of the rudder assembly for even easier access.
Another Modification--The Rudder gets an Uphaul
Because the rudder is way at the end of the boat (!!!) and the blade is quite deep, it is tricky to reach the rudder to lift the blade if I'm beaching or bringing the boat in. Since Most of the places I launch from are hard I don't like the rudder blade to drag on the hard concrete bottom so I have added a pull up string beside my pull down string. It fits exactly as the pull down set up with a hole in the blade but on the opposite side. I just cleat whichever the up or the down is supposed to be holding the rudder blade.
It was simple to route the 2 lines in the channel that is inside the rudder cheeks. I just had to be careful they were not twisted. It works very well.
In the end I have not used the groove and hole I made to route the lines forward of the rudder. It takes a strong pull to drop or raise the rudder and an extra turn would just add more friction.
Read about other boat parts being constructed
This web site reflects my personal ideas and doesn't represent anyone else's point of view. If you want to build a boat be careful. Tools can be dangerous. Get help if you don't know how to do something.