CapeHorn Wind Vane Ericson 38

I'm working with the famous Yves of Cape-Horn Windvanes as I wish to install a Cape-Horn Vane on my Ericson 38 Synchronicity. The question has been possed- What is the area of the Rudder... Would anyone have the answer to this question. I have 1982 Ericson 38' with the 4' 11" draft. Does anyone know the area of the Spade rudder on this boat?

Math Challenged

I happen to have a rudder in the garage, but can't remember the formula for the area of a trapazoid. Probably can't spell it either, but the measurements turned out to be 29" across the top and 18" across the bottom. The leading edge is 48" and the trailing edge is 54".

Using a formula found with that trusty tool Google I come up with 1128 square inches, but it also told me that a trapazoid has two parallel sides which the rudder does not. That means the small triangular area at the top of the rudder is not included since I used the non-parallel top and bottom as the base figures and the verticle leading edge as the height. A calculated guess at the areea of the triangle being 87 square inches leaves an estimated rudder area of 1215 square inches.

That may be close enough for your purposes, but perhaps you should just give Yves the measurements. If anyone else out there has had a math class since 1962 you might tell Captainspicy and I how close I came.

Another Method

Drew-up a quicky in AutoCad using the above dimensions, and came up w/ 1182sq. in.
I think as long as the "legs" are the given dimension the area will be the same regardless of shape? It's not exactly "easy" "Gee-I'm-a-tree"!

sleather said:

I think as long as the "legs" are the given dimension the area will be the same regardless of shape?

Click to expand...

I think that's only true of a triangle. With a quadrilateral you would need to know the length of the sides, AND at least one angle.

One Right Angle

There is one right angle at the bottom of the leading edge. Actually that is not true, since there is a short flat at the top of the leading edge where the rudder post exits the rudder. I was ignoring that to keep this simple.

Gettin' Close!

I assumed(danger, danger) a right angle(bottom/trailing edge) so it's gotta be darn close.

Rudder in the garage

THANK You Burgner. I really appreciate the effort set forth to provide this information. Can you confirm with certainty that the RUdder in your garage is from an Ericson 38? What was the draft of the boat this rudder is from?, what year was it launched? Before committing to the Cape-horn wind vane I want to try to make sure we size it right. Yves indicated the rudder area and quadrant radius were the 2 most important determining factors.... THe rudder info you gave is valuable so long as the rudder you measured and calculated is the same rudder that I have on mine. Please tel me what make/model/year boat the rudder is from.

THANKS Again! Cap'tSPicy

Spare Rudder

When I purchased my 1984 E381 a few years ago this spare rudder came with it. I purchased the boat through a broker and the owner was working out of country so I did not have a chance to talk with the owner about the boat systems or spares. It looks like the one on the boat and I have no reason to beleive it is not what it was claimed to be.

I am sure there is a good story behind how the boat came to have a spare rudder. If only boats could talk, huh? It would sure make troubleshooting easier.

Cape Horn Self Steering

Hi, CaptSpicy-
Please keep us informed of your experience with the Cape Horn system. I talked to Yves and his nephew at the Annapolis sailboat show about getting their system for my E35-3. I looked at all the systems at the show and the Cape Horn sure looks like the simplest and least cumbersome both on the transom and in the cockpit- no tiller lines to the wheel. It's also the most economical. The Hydrovane does have the advantage of incorporating a spare rudder, which no other self steering system does, but it's twice the price.
Anyway, I'd love to learn from your experience with the Cape Horn since we plan to purchase and install a system prior to going off shore. Thanks.