Steps in Building a SCAMP sailboat
Links to all my scamp building pages.
Making and Installing the 2 Skegs on The Bottom
SCAMP has 2 skegs on the bottom. These act to keep the boat tracking straight and provide a strong support when the boat is beached. It also helps protect the hull in case of a grounding or launching on hard surfaces.
The Skegs also get a routed cavity that provides a hand-hold in case the boat tips over. If the boat is on it's port side the centreboard can be quite high and having something to hang on is useful.
Making the Skegs was harder than I expected
I went shopping for a nice clean board. I figured a 2x12 spruce board would be wide enough to cut the 2 skegs and would not break the bank. The manual suggest a softwood and spruce is readily available around here.
I found a nice board in one of the big box stores. I swear I looked at every board in the store. This one was available because it was a bit damaged on one edge but that made no difference to me since I would be cutting that part off.
I also tried to find a longer clearish board to make the spars but no such luck. I bought clear pine instead. Not so strong but nice lumber. I'll make the spars just a bit thicker.
I used a board to make the pattern. Since it was not quite deep enough I glued a small piece on the edge. I used a piece of wood with a pencil through a hole to reproduce the curve of the hull. It worked surprising well.
I cut the curve with the band saw and although it was a bit awkward it worked out.
When I checked the pattern against the hull I found that I needed a couple of thin spacers at the very end so I glued a cut up tongue depressor and this worked.
I then drafted the skeg on paper and used the pattern I had taken off the boat to mark the bottom curve. I then cut the paper pattern out. I actually cut 2 copies so it would be easier to fit them on the board. I marked the board and prepared to cut the skegs.
This is when my troubles started. The board was too long and too heavy to handle on the band-saw. I tried with my little roller thingie that I use with the table saw, but I just could not handle the wood smoothly, or for that matter have enough space around the saw to swing the wood around the curves.
I decided to use the jig saw instead. It would be slower but I'm not in a rush. Jig saws are marvelous at cutting thin plywood but 1 1/2 inch board is asking a lot and I found that any blade long enough to cut through tended to bend and wander a bit. I managed to cut my pieces but the cuts were not perfectly square to the surface.
I decided to leave it for the night, since I was tired by then. I figured the smaller, lighter wood could be squared up on the bandsaw since the cut skegs were not so heavy.
Next morning I came to the shop to find my not square skegs had warped just a little overnight. The job of squaring everything up was more than I wanted to face so I gave up and went on sanding the hull till I figured out a new plan.
Take 2, I try another way of making the skegs
I am desperately bored with sanding the hull so it's a good time to get back to the skegs.
For my next performance I will cut a sheet of plywood and make a couple of skegs out of it. I hope...
I went to the lumber yard and bought a sheet of exterior grade G1S (good one side) 3/4 inch or whatever metric equivalent. We live in a country that sells sheets of plywood where the thickness is measured in millimeters and the length and width in feet. One face is very nice and smooth, the other face has slight knot holes and a check or 2 but otherwise smooth. I can work with this. I could get good 2 sides but the knot holes are filled with a kind of putty so no good for sitting in water.
I don't think I need marine grade ply. The glue is the same but there will be a few voids. Since I'm planning to laminate 2 layers, and glass the skegs I don't think strength will be an issue.
I asked the shop to split the sheet lengthwise so I can fit it in the car.
I plan to cut one thickness of plywood using the jig saw, then after sanding and checking the first plywood piece, cutting 3 more thicknesses using the router and flush trim bit.
I put a nice record in the shop cd player (Vieu Diop, Mali singer.) Wonderfully mellow and pleasant music to work with.
Luckily for me I had my paper patterns and the bottom tracing so it was a simple matter to mark a skeg outline on the plywood, and to cut it out using the jig saw.
After a bit of cleaning up and smoothing of the edges I checked it against the hull. It fit better than the original pattern after a bit of sanding. I then used my "good" copy to mark 3 more skeg pieces on the plywood. I cut them out roughly outside the line with the jig saw, and set up the router with the flush trim bit.
I don't much like using routers. They are noisy and frighten me a bit, but they are very useful. Anyway, I got the next 3 pieces cut without any problem at all.
The 4 pieces were perfect copies. I had used screws to keep them together and used the same screw holes to put them together to check one last time before gluing the pieces together. Square! Accurate! My goodness, could my luck be changing.
Used thickened epoxy to fill a couple of small voids and glue the 2 skegs.
I clamped the 2 skegs together to sand. Not much to take off. I used the router to put a small radius on the edges. I also need to rout out the handhold that help give a grip if someone is trying to right a capsized boat. Sometimes it's easier to grab the skeg before reaching for the centreboard. Otherwise they are ready for glassing.
Before I install though I want to prepare the aluminium strips I got to line the bottom of the skeg. Link to fitting and installing the metal strips to the skeg
The plan suggests making hand holds along the skeg to make it easier to grab on to in case of a capsize. The SCAMP centreboard can be quite high out of the water if the boat is sitting on its port side. Being able to hang on to the skeg is useful.
Since I"m planning to rout out the hand hold, I made a pattern using plywood.
Once the pattern is clamped on the wood it's simple to just rout out the depression.
This is the router bit peeking out of the collar. The collar follows the pattern and makes an accurate reproduction of the pattern but smaller.
After doing the routing I checked to see if the depression was deep enough to be easy to grab. It seemed a bit shallow so I placed the pattern back on and routed a bit deeper.
I made 2 hand-holds on each side of the 2 skegs.
Glassing and installing the skegs.
I started glassing the bottom of the skegs. I cut the glass too narrow to properly overlap the other side. They were too stiff and just stuck out on both sides. I had to think quickly and decided to wrap the glass with plastic to keep it down until it sets. Next come the sides.
I glassed the 2 sides of the skegs. After the epoxy set I put on another filling coat of thickened epoxy.
Once set I was back to sanding. I sanded everything smooth. Actually I'm lying, the sides are smooth but the tops and bottoms are a bit rougher. The skegs are now ready to glue on the bottom of the boat.
Deciding where to put the skegs required some thought. I measured my trailer to make sure the skegs would fit on each side of the support beams that run the length of the trailer.
I had a centreline but could not see it. I must have sanded it off or covered it. I had to stretch a line and make a new mark. After lots of measuring, checking, measuring again, checking diagonals, I settled on a position for the skegs and marked it well. I extended the lines so I could see it when the epoxy covered it.
Since things tend to slide around while gluing I decided to do each skeg separately so that it would be easier to control and position each one. This worked well. The epoxy was just starting to thicken as I was finishing cleaning up the squeezed out glue.
I finally got the second skeg glued and checked for position. Photo is odd, it looks like the skegs are not even but they have nice regular lines.
I added a line of fillets on both, cleaned up as best as I could and once set I'll be able to sand and finish the bottom. Finally.
If you decide to build a boat be careful. These tools can be dangerous. If you don't know how to safely handle something find out. There are lots of forums out there.
This web site reflects my personal ideas and doesn't represent anyone else's point of view. I don't claim to be an expert in anything, just someone muddling along.