Rudder rebuild - newbie questions

[dan-marques]

Hi all.

I have a '67 O'Day Mariner, which has a transom hung wood rudder. The rudder had been damaged (and then poorly repaired) by the previous owner, and now it is beginning to delaminate. The rudder is one solid block of wood, with two thin plywood(?) laminates on either side near the gudgeons (both are at the top end of the rudder).

I would like to repair or rebuild the rudder, but know absolutely nothing about boat building. (I have long wanted to build a boat, but have no space, a rudder being about the largest size project I can handle now).

I was wondering if anyone had some advice as to how I should go about doing this (do any of the books out there mention it).

For instance, how are the gudgeons connected to the rudder blade?
How do I do the lamination?

I ask these questions before taking it apart b/c I might decide just to patch it for the next few seasons rather than rebuild.

Thanks a lot.

Dan

[Mad McGee]

Hello there.

I am by no means an expert (some of the people on this forum know so much its sick) but here is my 2 cents worth.

Take a nice piece of hardwood (like mahogany). Strip it on your table saw. Then, edge glue it back together as board using epoxy. But...when you glue the strips flip each strip. This means that if any one strip tries to warp it will be fighting the adjacent strips (none of the grains are running the same way). Next run the board through a thickness planar. Finally cut the shape of the rudder out of the "board". I built a centerboard this way as a well as a rudder. it is astounding the strength in rudders/boards built this way. Also, although the strips are only held together on the edges by the epoxy, I have never had a joint fail...the wood always goes first.

A side benefit is that if you clear finish it the rudder will look very pretty.

ARM

[Peter Malcolm Jardine]

The gudgeons have two straps one on each side, and are probablly flush bolted through the main piece, with the two plywood pieces over them.

I would suggest that you carefully as possible take the rudder apart, and see how things are built. If you chew up the pieces taking them apart, you can make cardboard patterns of them to make a new one. You could use mahogany to replace it as suggested, or you could use marine grade plywood, and seal it well before painting it. Don't be to intimidated... if you have some basic woodworking skills this is a good project for you!! smile.gif

[ishmael]

It's a little hard to say from your description, but I'll bet you have a blade of solid mahogany, which is probably still sound, and some cheeks of ply that are where the problem is. Quite probably the mahogany is reusable. Are the cheeks glued or screwed? The latter would be much easier, they are probably both.

You'll have to unfasten, and/or pry and scrape off the plywood cheeks, fashion new ones and put them back. It ain't rocket science. The starter kit of epoxy from System Three would probably be enough glue.

Keep asking questions so as to give us a better picture.

[dan-marques]

Hi, and thanks for all the advice. Here is a more detailed description of the rudder's problems.

The rudder is a solid blade of mahogany (I assume), with two plywood cheeks. The cheeks are attached only by glue.

The rudder has two separate problems, actually. One is that the cheeks have begun to delaminate towards the bottom. They peel right off. Well, actually the outermost two plys peel right off the lowest ply, which seems firmly glued (aka hard to remove) from the blade.

The other problem stems from the fact that the previous owner of the boat repeatedly damaged the rudder by turning it into the spinning prop of the outboard. This caused two separate areas of damage. First, there is a 12in by 2in strip of the outer edge of the blade that is completely damaged, almost severed. The second is that (on the prop side) there is about a 2x4 inch "divot".

The previous owner attempted to fix those problem by using (what I guess is) wood filler, which was then covered with some red paint. He then coated the whole area with what looks like bondo (a gray material), maybe he damaged it again. Problem is, he either his material didn't dry (peeling it off, it still smelled like wet glue), or it still leaked, and all the wood is damaged under his repair.

I was wondering if I could just cut away the bad wood (cut a chunk out of the rudder), and replace it with a new piece of wood, edge epoxied to the existing blade.

Here are some questions. Would that be strong enough, or would I need to fiberglass it as well? If I don't need to fiberglass, should I coat the whole blade in epoxy? What kind of paint could I apply over the epoxy (I'm assuming I'll do the replacement with a different colored wood).

If that did not seem like a sound repair, I will build a new rudder, but I imagine a solid piece of wood like that would be expensive.

Any suggestions?

Thanks.

Dan

[ 03-06-2003, 01:36 PM: Message edited by: cfn ]

[Peter Malcolm Jardine]

Sounds like a new main rudder blade is in the offing..... The mahogany may not be as expensive as you think... and you could slice off the section that is damaged and expoxy a new one on... replace the plywood.. and seal the whole rudder before you paint or varnish it. I don't think I would glass it, but sealing it with epoxy wouldn't hurt. Sounds like you have a good handle on it.. ;) Use a sharp chisel to scrape off the final layer of plywood.. and don't replace a "chunk" replace a vertical slice, that way you get a nice long glue joint, and its easier to patch in. You could buy a piece of mahogany big enough to use for the cheeks and the repair, and I don't think it would cost too much.

[ 03-06-2003, 04:21 PM: Message edited by: Peter Malcolm Jardine ]