Home-built swing rudder

[ulferlingsson]

Since my new Sailing Yacht came with a non-fitting, non-folding, messed-up rudder in poor shape, I decided to build a new one, and this is it. From these pieces of SS 316 I welded the rudder stock:



Some pieces of plywood formed the core of the rudder blade:



After 5 layers of glass fiber, and gelcoat, has been added this is what it looked like:



This is some additional SS 316 hardware for mounting the blade to the stock, and a custom-made pin for the gudgeons (not visible is a bushing that is epoxied into the rudder blade):



The bushing around the bolt goes from washer to washer and fits tightly in the holes of the stainless plates. The bushing in the rudder blade meets the stainless plates on the inside, but the gelcoat does not. Thus, the rudder blade is rotating somewhat freely. So how to keep it in place? Using an elastic chord, as follows. The line is attached to the rudder blade in this device:



...and comes out in the top under the tiller here:



By the way, the tiller is made of anodized aluminium. Lighter than wood

Yesterday was the maiden voyage, and it worked as planned. We had an unfortunate chance to test the function; in the canal we apparently hit a manatee We did go slowly (it's an idle speed zone) and the swing keel was not locked so it swung up, and so did the rudder. It all worked and hopefully the manatee did not get seriously hurt. Pulling in the shock chord brought it back down.



If I decide that I need to be able to pull it up manually, I will add a chord on the rear side of it. It can attach to the back side of the stock.

[scottyt]

where did you get the rudder profile from? why did you use ply instead of foam? lets hope the glass work is sealed well

[ulferlingsson]

The rudder profile is NACA 0012, I took it from their original report which is somewhere here in cyberspace. For lack of proper foam I used plywood. This blade was meant for testing and temporary use. My intention is to make a blade in stainless steel for permanent use, and with wind rudder functionality. So I wanted to check the size, the profile, and so with this first.

[sailingdog]

Why would you want to make a rudder out of stainless steel???

[ulferlingsson]

I have been thinking about that question for over a year now. Well, the thing is that to get wind-rudder functionality with the mechanism I have in mind, it has to be made of sheet metal, and then stainless is a good choice. Aluminium would also work, though. Built like an air plane wing.