Steps in Building a SCAMP sailboat
Links to all my scamp building pages.
Making the Rudder Case
I've been working on the hull but needed a break from that, so I came back to the rudder. I also needed to commit the wood to the rudder parts, so I know what I can use for backing plates and other bits and bobs.
I had made The rudder. The foil still needs a bit of help but the top part that connects to the rudder case is mostly finalized, I'll need to smooth out some of the curves and fiberglass it but otherwise I'm ready to work on the case.
Figuring out the rudder and making definite plans
I went to the plan sheet but it's quite frustratingly vague in the details. A few dimensions but no exact lines. "Shape to suit" is a bit scary.
I made a paper trace of the rudder I built, and made a rough draft of the rudder case. This helped me start to visualize how they work together. It is also a really good way of figuring out what needs to be exact and what can be variable.
After a bit of fussing I drafted what I though would work and cut it out. This way I could check if the parts pivot correctly against each other and if it look "SCAMPY"
I also took the paper templates to the hull and checked the positioning of the rudder. No red flags but I realized that the channel for the up and down lines needed to be quite close to the bottom of the tiller to fit nicely in the transom opening.
I had to add bits and pieces and modify the lines a bit but I'm satisfied that the rudder will pivot with no problem.
It also helped me visualize where the lines need to be routed and where the tiller goes and how much it can move up and down.
I pulled out the pieces of plywood set aside for the rudder and started fitting the case pattern pieces on. If I don't ruin a piece I'll have enough.
When I made my puddle duck rudder, I made the blade too tight against the case. I had to sand and fuss to get it to swing up and down easily. So I also checked the thickness of the SCAMP rudder blade to make sure that the case would be large enough. I have to estimate some because I will be putting a few coats of epoxy on the case and blade, then a few coats of paint.
I cut the pieces and check that they fit.
I was able to mark all the parts on the plywood and rough cut it. I left at least an eight of an inch all around each of the pieces so I can tweak them if I have to.
I also rough cut the position of the up and down lines.
The reason I did not cut the pieces to size or almost, is that I am not 100% confident that I'm right in the plan and I want a bit of wiggle room to adjust if I have to. This means more work but a slight level of safety.
I put all the pieces together, using small temporary nails, and made my first accurate cut along the back. I had taped the pattern on the pieces to make sure everything would fit. I put a 1/2 blade on the band saw, adjusted it to within an inch of its life, took a break, looked at the fire, then steeled myself to cut. The cut went just fine. I also cut the very bottom of the case.
My next cut was the top curve all the way to the bottom. I had marked it with a dark pencil and just took my time. At this point the outside of the case is cut so I separated the outside pieces from the pile.
I was now confident I could cut the curve that runs along the rudder blade as it rotates. In this curve there is a channel to allow the down line room to come inside the case.
After putting the outside of the case back on the bottom of the case, I put a nail in the outside panel where I had marked the pivot point and put on the rudder. I was able to check the pivoting of the rudder against the case. I needed to make small adjustment to the rope channel and move the pivot point by an eight of an inch. Otherwise the fit was accurate enough for me. There is a bit of space which I expect will be filled by the glass of the blade when I put it on and the various finishing coats which are still to come.
I prepard a copper pipe to line the channel for the up and down rudder lines.
Back to the transom with my pieces to check if the marked position for the tiller channel would work allowing the tiller to go up and down somewhat and to swing freely in the opening. Everything looked fine, so I cut it on the inside pieces.
I have seen other Scamp builders put copper inside the rudder to make a smooth path for the up and down lines. I though I would try this. I don't think it is particularly necessary, I was just curious to see how well it works.
I flared the end of a 3/8 copper tube using a plumb level and a round steel rod with a curved end. There are nice little flaring tools available from plumbing supply but I don't have one. The hardest part was keeping the tube in place without damaging it. Finally I drilled a hole in a board and cut the piece in 2. The saw took just enough material off that I could clamp it and hammer lightly on the end.
I cleaned up the edges of the channel to the proper width, and used a chisel to deepen the slot so that the pipe fit. I used a round file at the ends to make a tidy round hole and tried the pipe in the channel. It took a bit of bending and pushing but eventually it fit in without protruding. I did the same for the other side.
I'll use thickened epoxy to bed down the tube and fill any space.
I line the pivot holes with Bronze Bushings
I dug up the bronze bushing pieces I had bought when I made the centreboard. These will be used to line the rudder pivot point. I already have a 3/8 bolt that fits the inside of the bushing.
I clamped the bushings and cut them. The metal is quite soft and it cuts easily. I have to be really careful to cut as straight as I can otherwise it's quite a job to sand/file it flat. I sanded and cleaned up the sharp edges.
I also cut a few grooves on the side to give the epoxy something to grab onto.
I have this very fabulous 5/8 forstner bit, it makes a lovely accurate hole and has minimal tear out. I could have used a spade bit. If they are sharp they work really well too. Better to make a pilot hole and finish the hole from the opposite side to avoid tear out though.
Hardest part was making sure the wood was aligned and clamped accurately on the drill press table. When I glue the bushings in place I will have to sand the inside of the hole just a bit to allow for the glue to get in. Epoxy does not like too tight a fit.
I put in the bolt and checked that everything still pivoted correctly and no red flags appeared. So far so good. I measured the slack and it's about 3 mm. I think I need a bit more because I plan to have a washers on the side of the blade as well as a space. I can adjust that spacing when I glue the inside parts of the case together.
I spent some times readying the blade for glassing, mostly sanding. I also laid out the parts for the copper channel pieces.
I prepared the glass ready to grab and apply.
The blade is glassed. I'll need to touch up the edges of the trailing edge. I will also need to put a strip of of glass on the top of the blade.
I intend to glass the inside and outside of the case outside pieces. There will be some friction wear from the rudder and from the tiller.
The instructions say that the cheeks do not need to be glassed. I did anyway.
The copper pipe is glued in with the surrounding parts. I will do all the pieces separately to control the process better.
Temporary screws are in place holding the parts aligned. I'll go in later this evening and remove them to avoid the screws getting glued in and having to be extracted. I had to do that for a few in the floor of the scamp when the heads of the screws broke off.
Next morning I cleaned up the pieces and glued the 4 layers together for the inside pieces. This is the pieces with the copper channel and the top piece with the top outside curve on one side and the tiller channel on the other side.
All I have to do for the case now is clean up the glued up pieces, make sure the glass is filled on the cheeks and assemble everything together.
After the epoxy set, I did a rough clean of the glass and the copper pipe. I'll use the belt sander on the edges when everything is glued up.
I installed the bronze inserts in the rudder case cheeks. Sanded the hole then put some tape on the back to keep it flush. Some thickened epoxy went in and after cleaning up the squeezed out extra I let it set.
The weather has been quite cold and my epoxy started crystallizing. I put it in front of the stove to warm it up some and hopefully get rid of the crystal and liquefy everything. It seems to be working. I don't think it damages the epoxy at all. I've done this before with MAS resin and it worked very well.
I can't think of any reason to procrastinate putting the rudder case together any longer. The inside are glued together, the cheeks are epoxied and sanded. I've made pilot holes for screws to align and hold everything together.
It was a simple matter to spread thickened epoxy on the pieces and screw them in place. I also put some clamps to make doubly sure it was well clamped.
I spent some time removing any squeezed out epoxy from the interior spaces. Now it will be difficult to sand or access the inside spots.
Now all I have to do is make sure the sides are even. I had not cut the pieces to size so this needs to happen. I expect I'll use either the belt sander of random orbital sander for this. I have some good files which will help.
I wasn't too sure how to glass the edge of the rudder blade. I put a line of tape at a 1 inch distance from the edge, then, taped the glass behind this line. I turned the blade over and did the same thing on the other side. The resin went on without too much trouble and for the most part the glass is smooth. I have a couple of spots that seem to have bubbled but I'll fix that when it's set. A similar method had worked with the centerboard.
I will go this evening when the epoxy has set but is not hard yet and trim off the extra at the tape line.
I put a strip of glass on the top edge. I had creased the glass at the sharp angle and that worked.
I had also used a similar method when I glassed the edge of the Puddle Duck Racer (photo above). To stretch the glass I had used staples instead of tape but it had worked.
After supper I went and trimmed the still gummy epoxy and glass and burnished the edge so that the burr on the edge of the cut glass went down smoothly. The glass went down quite well. There are about 4 small bubbles that I pressed down. It was just sticky enough that it might be enough to get them to lay flat.
The top of the Scamp rudder is now glassed. I trimmed it while the epoxy was not quite set and polished the edge so there is not much glass sticking up. I don't think there is much stress on this part so glassing it is more for protecting the finish than for strength.
The blade now needs some holes for the up and down lines and a couple coats of epoxy to finish filling in the glass. The photos make the edge look milky, I think that's an effect of the flash because the edge glass is almost invisible. At this point some sanding, and finishing and I have a rudder blade.
The case after some sanding is shaped. There is not much more to do. I still need a hole for the tiller retaining clip, some filling of screw holes and some uneven spots, and general finishing.
I need to locate the clips and decide on pintles and gudgeons. There are practical Racelites ones from Duckworks but they are not particularly pretty. At the other end of the spectrum, there are gorgeous bronze ones from Davey & Co but very pricey by the time they are delivered.
I eventually decided to go with the Bronze ones. I'm getting them from Tendercraft. A small boat shop that caters to wooden boat builders. They are located just outside Toronto and regularly deal with Davey &: Co.
I've been working on the hull bottom but have some time because epoxy is too soft to sand. I decided to work on the rudder.
Using the drill press I made a pilot hole in the spot where I wanted the pin that holds the tiller in place. I'll be using a 3/8 inch bolt with a Nylock nut. That's what I had on my Tanzer and it worked well. I don't think I will put in a bronze bushing because there is really not much stress on the hole. Unlike the rudder pivot, this hole is just there to keep the tiller in place. If it starts wearing, I can put a bronze bushing later.
I made a pilot hole with a 1/8 bit, then positioned the tiller in place and re drilled the pilot hole to include the tiller. I then separated them and used a 3/8 bit to make the final holes. I had to enlarge them to allow for paint and epoxy but I did not have a suitable larger bit so I used files to make the holes larger.
The case is sanded I cut the grooves for the pintles and gudgeons.
FINALLY I got to paint something! I'm using Brightside from Interlux, polyurethane. I chose this for the colour more than for a brand loyalty. I looked at 2 part polyurethane but decided against it because I like having small amounts of leftover. If I mis-judged how much paint I needed with the 2 part I could easily end up wasting a lot. I've used this paint on my keelboat and on the tender and it has worn very well.
This blue covers much better than the white I used before and one coat left an almost flawless surface. (well almost flawless, except for the dust and the somewhat rough spots I left.)
The Pintles and Gudgeons have arrived and I fitted them onto the rudder case
I went on to finish the tiller.
This web site reflects my personal ideas and doesn't represent anyone else's point of view. I record the process I have followed and the result. I am not saying that it is the right or best way. I'm not a greatly experience builder. I just sort of bumble on and try to do as well as I can. Hopefully I get a boat at the end.