Steps in Building SCAMP
- What's a SCAMP and why am I building one?
- Drafting and Cutting the plywood
- I continue to lay out and cut the plywood pieces
- Making the SCAMP mast/cutting lots of strips
- Making the centreboard
- Centreboard pivot and details
- Making the SCAMP rudder
- Extra details on shaping the rudder
- Making the Rudder Case
- Making the support cradle/frame
- Bottom and centreboard case + bulkheads 4 - 7
- Turning SCAMP over
- Stem, bulkheads 1 - 3 and mast trunk
- Water tight (I hope) doors for the hatches
- Working on back and transom
- Installing the side planking
- Fore and side decks
- Installing the bow eye
- Side benches/ hatches
- Making the portholes/deadlights
- Under cockpit compartment and ballast tank
- Installing the 2 layers of the floor.
- Oar Socket Placement
- Making the tiller
I started the Scamp rudder.
I looked in the leftover plywood pile and cut out some blanks to glue up the Scamp Rudder blade. I put a couple of pieces through the thickness planer to slightly reduce the thickness so now I have a quite accurate pile of wood. A little epoxy precoat so the glue will not be absorbed. This new epoxy I'm using the East epoxy is thinner than the MAS so rolls on slightly more easily.
I used slotted spreader and used thickened epoxy, (silica and wood flour). I had little wooden spacers on the table so I could put my clamps on. Just enough squeeze out to reassure me that the panel has glued properly.
I had reserved one of the four pieces of ply and not glued it on. I will glue it on after filling the blade with weight.
Meanwhile, I put in temporary screws and drafted the rudder onto the board. I'll cut the blank and decide where to put the weight. It does not have a flat spot like the centreboard so I'll have to be accurate in routing so I don't cut into the cavity when I shape the rudder.
After cutting the shape of the rudder with the band saw I fine tuned it using the belt sander, files and finally my random orbital sander. I just picked up a package of 40 grit paper and it is quite aggressive and useful for shaping.
This was not my most accurate band saw performance so the shaping took a bit of time.
I copied the plan rudder template to a piece of card by taping them to the window and tracing the shape on the cardboard. I then used the bandsaw to cut out the shape. I'm not entirely sure how to shape the rudder even with the template though since it is not a rectangular shape.
I marked the centre of the blank on the edge with a felt pen. It makes it easier to have a good mark to check against when shaping the foil.
I put a few reference marks on the edge and took off the top piece of plywood and set it aside, I had not glued it on to make it easier to enclose the weights inside the Scamp rudder.
I used the drill press with a forstner bit to make a series of holes, using a stop to keep the depth even. It was faster than using the router for such a small cavity. The instructions ask for about a kilo of weight but my plywood is heavy and I'll put in less. My centreboard turned out heavier than I expected.
It took no time at all to clean up the holes with a chisel.
After sealing the hole with epoxy placing the bits of metal and sand in the cavity I epoxied the weights and left the assembly with a piece of flat plywood over a sheet of wax paper. I'm hoping the cavity will be flush and I can just glue on the top sheet of ply and be ready to start shaping the rudder.
The surface turned out to be flat and almost flawless. I filled a couple of small holes and put thickened epoxy over the whole rudder blank surface. It was a simple step to align the top piece of plywood because of the screw holes and the marks I had made on the side.
Here is my rudder blank a-bristle with clamps. There is just enough squeeze out to make me happy. I can start shaping tomorrow.
I'm using East Epoxy
I'm making this boat using East Epoxy. So far it has performed very well. It is a 1:5 mix by volume or 100:18 by weight. It has not blushed at all. I have a few sets of test boards sitting around and so far no blush on any of the pieces, nice surfaces, good glass adhesion.
The epoxy sets smoother than I'm used to and is sandable faster. Manufacturer claims that it is completely set in 7 days.
It is slightly stiffer after setting than MAS which I've used for years. It is runnier after mixing and is easier to brush / roll on, and soaks in the wood with no problems. It wet out the cloth easily.
I decided to use it because of the price, and Noah where I bought is a reputable dealer and they like it. The Canadian dollar is not very high right now against the US dollar and this epoxy is a bit over a third the price of others. I expected it to blush but so far not the slightest blush, a nice smooth clear finish and excellent flow and wetting. It sets quickly to a sandable surface. In my shop I can sand after setting overnight.
The wood-epoxy bond seems adequate and in the joints I tested, the wood failed before the epoxy.
I'll let some of my samples sit till fully cured and I'll soak them to check their water resistance.
Shaping the Scamp Rudder
I puzzled over how to shape the rudder. In the Centreboard shaping I had been able to use the router to shape the almost parallel sides but here the shape was much more rounded and needed to blend in the tip. There is not one profile that would work so no router shaping.
I took many more photos and more detailed description of the process of SHAPING THE SCAMP RUDDER and put them here. It may not be the best possible way but it worked for me and was relatively fool proof.
After a quick cleanup of the squeezed out epoxy the rudder blank is ready to be shaped.
I have markded the blank with depths and contour lines so I have a good idea of where I want to cut and how deep.
I wasn't quite sure how to shape the rudder so I used my template cut in 2 and shaped a short section in the leading edge until that had the proper profile.
I then extended this good profile to about 8 inches from the bottom
I then went on to the trailing edge and shaped a short section with the mostly correct profile. This I also extended to about 8 inches from the bottom stopped near the bottom.
I then blended the cut so that there would be a smooth transition in the bottom.
The layers of the plywood make it possible to fairly accurately shape the rudder by making smooth lines, however not all plywood is even and some will have flaws.
I then blended the cut so that there would be a smooth transition in the bottom.
This is NOT the finished shape, I will need to smooth out and fine tune some of the areas and work a bit more on the tip.
Once I have a side I'm relatively happy with I will take a photo and use that to match the second face of the rudder. This combined with the templates should help me get a fairly accurate duplication of the 2 faces.
I went back to the rudder and worked on the shape some more. It's a bit more regular and smooth. I can start on the assembly now that I have a mostly shaped rudder. I expect I will be fine tuning the top part when I see how it looks when it pivots in its case.
The rudder is formed and is almost the same on both sides. It took a lot more work to match the 2 sides than I expected. One problem was that I did not assemble the plywood blank symmetrically. This means that the plywood bands should not be identical on both sides! I also have a slightly thicker epoxy band on one joint than on the other. I used my templates more. Still a bit of final shaping but I'm almost ready for glassing.
In terms of time it would be well worth the money to purchase the already shaped foil kits that are available. I am hoping to build very economically so I chose to shape myself. Not much compromise in quality but it took a long time.
I made a stand to hold the epoxy resin and hardener. I mostly measure by weight so my scale and calculator have a spot. In the shelf I will add filler and thickeners as well as mixing tools. It will keep my precious counter space free and will keep the epoxy stuff in one place conveniently close to where I plan to assemble the Scamp.
On to: Building the Rudder Case
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.