Shaping a Rudder from Solid Teak

trewheeler · #1 (**permalink**) 11-12-2009

Hello, Just joined this forum today. Last week I picked up a 1976 Catalina 22 (hull# 6350) and brought her home to Tallahassee, FL where I will be getting her ready for the water. She is my first boat. I have crewed years ago in the past and have worked on a couple of boats as well. I am originally from the coastal village of Brightlingsea in England where sailing abounds, so it's about time I learned how to do it!

She's a swing-keel version and is a few jobs away from getting wet. I have a new keel winch and cable to install. Two large pieces of teak to join together and shape into a rudder and a new stainless mast seat. Other than some general cleaning and scraping - that's about it.

My first question, and if anyone can guide me because I've not found much yet, is a good link for planing your own rudder and what airfoils people recommend for solid teak (it's about 2" thick). It's not going to be a kick-rudder and is currently close to 6ft in length!

The other question is how do I inspect the pivot at the bow end of the keel? Do I have to raise the boat and lower the keel, or is there another way to take a look? It seems that this is rather a lynch-pin of the whole boat and I would like to see it / replace it before I get her on the water.

Many thanks and I look forward to hearing from you,

Tim

deniseO30 · #2 (**permalink**) 11-12-2009

Teak??? Gawd it's gotta be cheaper to buy a foam replacment! but if you insist the way to "fair" it is to make the shape on card board and use it on edge to see how the work goes as you plane it with an electric hand plane. the leading edge should be fat and like an airplane wing to the trailing edge. And all that $$ will wind up as chips on the floor! the complete rudder assembly: Catalina Direct: C-22 Kick-Up Uni-Foil Rudder w/Pintles & Tiller
and just the replacement:Catalina Direct: C-22 Standard Rudder Only HDPE

Cant' help you on the swing keel even though I had a hunter with one. the pin I think is sealed over.

deniseO30 · #3 (**permalink**) 11-12-2009

oh.. to really copy a rudder from the original would be easy. you would need to make edge templates out of cardboard about every 6" Unless you have lofting abilities which is a way of developing the shape every few inches kind of like if you sliced the rudder like you would a banana. boats are built the same way. .. there is a home use version of a CNC router available.. for $$$$$ ;(

Faster · #4 (**permalink**) 11-12-2009

I'd save the teak for more decorative work...Laminate a keel with less expensive woods and glass it over. There are many slightly different foil forms available, Catalina may well tell you which to use.

trewheeler · #5 (**permalink**) 11-12-2009

Thanks for the reply. Well the two lengths of teak were part of the deal, he even threw in an electric planer! It was just another job too many for him - his loss - my gain?

I really don't have a template or anything to go by. I have seen some NACA airfoils on-line that I could copy and just wing it. Or, I could copy the designs for replacement rudders in the Catalina catalog.

How perfect does it have to be?

deniseO30 · #6 (**permalink**) 11-12-2009

I can't imagine useing teak for that when so many other things it could be used for. Teak has silica in it and will wear down the edges of any sharp tool very quick. You do realize your going to waste close to third of the stock? Also the teak will be very heavy! You will need BIG pintels to hold it to the transom! You could also contact some of the FLA boat salvage places that have parts. or even look on ebay.

trewheeler · #7 (**permalink**) 11-12-2009

True Denise, but imagine what a glorious (and heavy) rudder I would have! I'll make some calls though! Also, I'll post some pics of it tomorrow because it is already partially shaped (outline, not airfoil). Tim

deniseO30 · #8 (**permalink**) 11-12-2009

well if you insist.... find a wood shop with a large band saw (resaw) and slice some the waste off. you will at least have some teak left over. Still you will have weight of a small outboard + the weight of real outboard. on the back of the boat. Front edge should be shaped like a rounded Vee, the very shallow curve should start declining almost straight back to about a 3/8" edge. the hard part is to get both sides looking the same. you NEED templates.

trewheeler · #9 (**permalink**) 11-12-2009

Boat Mechanical Systems Handbook ... - Google Books

Page 171 looks like it has some good templates. Figure 10.6

hellosailor · #10 (**permalink**) 11-12-2009

Check the web, there used to be some free software available online to generate NACA airfoil templates to user-set parameters. Once you print those out, the rest is just patient sanding and scraping, isn't it?

I can't help thinking that an HDPE board or something similar would be easier to shape, lighter on the boat (weight at the ends is bad), and perhaps even more durable than teak.