RebelCat 5 Update October 28, 2009

Two New Rudders

The first rudder did okay for some time, but like the CB, water got inside the plywood and caused some swelling. But the plywood was better quality than the CB so it did not delaminate.

What it needed was more power on a turn in low wind - big expectations for a small rudder on a 21-foot cat. So I improvised with some aluminum siding bent over and screwed on, then the edge covered with duct tape, like so...

I was so pleased with the performance of this quick fix that I decided to design the new rudder and centerboards using this kind of wood-aluminum blade. I recently discovered another sailor using an almost identical rudder. And it starts with a piece of Oak.

So starting with an oak plank 3/4" thick by 5.5" wide, I begin shaping the edges with an alectric planer and sander.

This heavy-duty sander is great for taking wood off without splitting it or gouging it. Like the CBs, only the front-facing edge needs to be shaped. The back will be aluminum sheet.

This is what results from shaping and sanding: a rounded bottom corner, a sharp but not thin leading edge, and a flat back edge.

Another view of the shaped rudder.

Here, I've glued an oak disc on the top end to widen it for the rudderstock. The aluminum sheet is bent in the middle and folded over to form both sides. This is thinner than that used on the CBs, so it could be bent easily. I'm trying out the aluminum here in the exact place where it will be attached, but first...

The rudder must be sealed with epoxy before attaching the aluminum.

Holes are drilled and then countersunk to the screw heads sit below the surface a bit. Careful here - it's easy to go right through the thin aluminum.

Screw the aluminum down, but drip some epoxy in the holes first to make them waterproof.

Both rudders have been drilled for the pivot. The holes are larger than the pins that hold them. You'll soon see why...

With a keyhole saw, score the holes with notches. I experimented with two ways, more notches and less, both worked fine.

Mix some epoxy, add fibers from polyester cloth, masking tape the back of the holes, and fill with the mix.

Using a sharp or pointed object, poke into the notches until all air bubbles are gone and the mix has filled the holes.

The drilled out hole in the new rudder. The hole is the same size as the pin/bolt which passes through it. Neat, no?

The old rudder's hole is drilled. Both work perfectly and protect the wood from water.

New rudder (left) and old rudder refitted are done. Camping-mat foam was stuffed into the space in the aluminum to prevent water from swirling in it.

I use the new rudder exclusively; the renewed old one is a backup.

Check out the new centerboards.