Rudder

Skorpa's rudder hangs down into the water about 2 1/2 feet. The rudder needs to be able to swing up when the boat is in shallow water.

So I need to build a kick up rudder. The blade will have a foil shape much like the centerboard.

The rudder blade is in fact constructed in a similar manner to the big board.

Vertical grain cherry and walnut strips were glued up to form a blank and then worked into a foil shape.
My favorite shaping tools are in the photo. The tools seem to work in some situations and then sometimes not.Then I either sharpen the tool or try a different tool until something works.

The shaped blade has been sealed with unthickened epoxy and is waiting to be covered with glass cloth.

The extra glass around the edges will be trimmed when the epoxy has firmed up but before it gets rock hard.

In this photo you can see where I have made epoxy bushing around areas where there are holes into the blade.

You can see the pivot pin protruding from one bushing. The upper bushing is for the stopper knot on the uphaul line.

These are the rudder cheeks. They house the blade and hold the hardware( pintles and gungeons ) that attach the rudder to the boat.

The third and last time.

The bottom is glassed and painted. The keel strip is screwed and bolted in place. It is time to roll the boat back right side up.

 This getting to be a familiar routine. First step is to roll the boat into the driveway.

 Then invite some friends, neighbors, and relatives over.

There is a lot of weight on the relatively unsupported inwale.

I have temporary thwarts in place but the inwales will be much better supported when the deck is in place.

Here six of us are picking the boat up and moving it back onto the building frame.

Sanding and Painting the Hull

I applied the epoxy carefully but I still had some sanding to do after the epoxy had set good and hard.

I made an adapter so I could fasten a full sheet of sandpaper to my sander. The big sheet of sandpaper floated over the hull and did a good job of  smoothing the hull without making dips or gouges.

Once the hull was smooth and fair I applied two coats of epoxy primer. I could not get the primer to apply smoothly so my paint job was disappointedly rough. It looked like one of my better stucco jobs.
The paint I am using is a Devoe product intended for industrial application on things like bridges and water tanks. The paint is formulated so it can be sprayed. It took me awhile to learn that adding a little of a special reducer T-17 slows the drying down and makes applying with a roller much easier.

I did the painting outside under a tarp for maximum ventilation.

I did not get the near perfect finish I had been hoping for but after a bit of scrambling and a lot of sanding I was able to salvage a decent looking finish coat.

White is to minimize heat absorption  to and maximum visibility.


All white is just too plain so I am adding some contrasting color. You can see the masking in place for a dash of red.

Before the hull can be turned back over I need to attach a keel strip that is protected by a metal band.

I bought 18 feet of stainless steel 3/16 of an inch thick by 3/4 of an inch wide. The steel needed to be drilled and countersunk for screws every 6 inches.

Sally's brother David kindly let me use his heirloom drill press.

The 316 stainless is not easy to drill. Lots of cutting oil and a bit of smoke.

The screws fasten the steel band to the keel and the keel is epoxied to the hull.

The steel band is intended to prevent wear to the hull when beaching, running aground or loading on the trailer. I thought it could also serve as part of a system to ground the aluminum masts in case of a lightning strike.

So just below the main mast and just below the mizzen mast I have placed bolts that go through the hull.

Where ever a fastner penetrates the hull I drill an oversize hole and fill that with epoxy. After the epoxy hardens I drill the proper size hole for the fastner. This helps prevent any water that penetrates around the fastner from getting into the wood.

A straw and syringe allow me to fill the hole from the bottom up so there are no air pockets left in the hole.

While the boat was upside down I decided to paint a boot top. I painted a 3 inch stripe of gray centered more or less on the waterline and topped that with a 1 inch stripe of red.

Originally I was going to use bronze as a keel strip and bronze half oval at the bow. Bronze is a much better conducter of electricity than is stainless steel. I had a difficult time finding a source for the bronze. Bronze is also highly reactive with aluminum. So after a lot of hunting around for bronze I went back to the more commonly available stainless steel.

Getting a clean paint line when you are taping off one color from another is not easy.

Those little bits of red are called flags. That is where some of the red paint seeped under the tape.

I learned a neat trick to prevent flags from occurring. It requires an extra step.

After you apply the tape. Paint a little of the base color, in this case white along the edge of the tape. Let that dry. If the paint finds a way under the tape it will leave a little white flag and seal the path so no red can follow.

Much cleaner edge using the two step process.

I have organized a boat rolling party for Sunday.

So while the paint is drying I am working on the rudder.

Glass Bottom Boat

Skorpa is primarily made of marine grade plywood. Fiberglass is used to reinforce areas of high stress and to protect areas from abrasion. The fiberglass I use is a woven cloth like material. Fiberglass can be made from synthetic materials, but what I use is related to the fiberglass that is used to insulate houses. Glass fibers are spun into thread and woven into cloth.

Here the hull is draped with 6 ounce cloth. I carefully laid the cloth out and worked to smooth out all the wrinkles. When I had the cloth fairly smooth I tacked it in place.

The epoxy is poured on and spread with a squeegee. As the epoxy soaks into the cloth the fibers become transparent.You have to put enough epoxy on to saturate the cloth but not so much you float the cloth off the hull or start runs of epoxy. You have to use enough pressure to move the epoxy but not so much you move the cloth. Is there any wonder I have trouble sleeping the night before?

The roller works best on vertical surfaces. I can get a thinner layer of epoxy. Building the epoxy up in several coats allows me to get the desired thickness without runs.

After I have the epoxy spread out evenly with the roller I go over the surface lightly with a foam brush to remove any air bubbles or roller marks. This leaves a pretty smooth surface so there should be less sanding to do.

Finding the centerboard trunk

Before I glued in the centerboard trunk I drilled a hole through the hull in the area covered by the inside of the trunk. This allowed me to know the location of the trunk now that the hull is inverted.

I made a jig to hold the router roughly perpendicular to the trunk and started the cut in the locating hole.

Similar to the way I cut out the seat tops. The router with a bearing tip did a good job of following the inside of the trunk.

After the slot was cut I could not resist temporarily installing the centerboard.

Here the board is retracted. The pin is installed. Seems like a nice fit. No extra wiggle room.

After I got the board back out of there I used the round over bit to (duh) round over the lip.

I used fairing compound to fill any small hole or imperfections at joints in the hull. Then a light sanding and the entire hull was sealed with unthickened epoxy.

I used a combination of squeegee and roller to spread the epoxy.

A foam brush is used to remove any bubbles or marks left by the roller.

Now the hull is ready for glass.

Move em out and roll em over

Sally and I rolled the boat out and a few neighbors came over to flip Skorpa back upside down so I can glass and paint the bottom. I cut the laminated stem flush and thought this made an interesting photo. You can see the inwales where they join the stem and the plywood hull panels meeting at the bow.

This is my second time flipping the boat so things were fairly relaxed.

Four of us were able to flip the boat with no problem.

When the four of us picked the inverted boat up to set it back on the frame we had the full weight which I think must be around 400 pounds.

A visit from the Designer

Graham Byrnes stopped by on the way between a boat show at Mystic and some boat building classes in Maine. He and Beth stayed a couple of nights with us. One of the reasons Graham stopped by was he wanted to see how I am coming along on my boat. No one else has built an EC 22. Graham has made several changes from the first EC 22, Southern Skimmer, so he has been following my build with interest. 

Graham said the boat was looking great.

He did notice a few places where stringers which stiffen the hull end abruptly at a bulkhead.

Graham referred to this as a pin joint.

Though the photos look much the same here the stringer continues right through the bulkhead.

This forms what is called a fixed joint. Much stronger. It is not always practical to continue the stringer through the bulkhead. You can taper the stringer and bring it to an end a few inches beyond the bulkhead.

Graham suggested that I place a fillet and some fiberglass around the area where the stringers end at a bulkhead. He thought that would distribute the stress and prevent any problems from developing.

If you look closely you can see a fillet and some fiberglass around the area of the stringer to bulkhead joint.

I was a little bummed when he told me about my pin joints but it did not take that long to patch them.

They look much better to me now.