rudder discussions

[Jon]

Jerry,

I have spent some time on the rudder board, but there are a lot of discussions out there and it's easy to get off the subject and on to another. Having said that, I'll go through it again and see what I can find.

I think that I've seen a rudder that has been braced like this one time and I'll state upfront that I don't know anything about it, but it would seem to me that when you get to this point it's time start thinking about a replacement and that's what I'm inclined to want to do anyway. The shoe and the bronze couplings that hold the rudder in line seem to be a pretty fair shape and the fitting is snug. Although I haven't sailed this boat yet, the rudder doesn't seem to have any play or looseness from the tiller.

You mention a company that will build a new one from fiberglass. Out of curiosity, what do they want to charge and have you any idea of the turn around time?

[Commander 147]

Jon

When I spoke to Bob at Foss Foam I was willing to provide the silicon bronze shaft (because I wanted to make sure I got the alloy I wanted) and I was told it would cost between $2,000.00 and $2,500.00 plus another $1,200.00 for the mold which he verified he did not have to match what I needed. That is when I decided to build my own. But I have been a woodworker all my life so for me that is not a problem.

I'm guessing in the current lousy economy we have here in Florida (which is also where Foss Foam is located) they could turn it around in a couple three weeks.

[Miro]

Hello Jerre!
I recently became owner of an Ariel. I just fell in love with this old beauty and I want to restore her to her former self. I want to do as much original nice quality wood and finishes as I can while rebuilding her. I need to replace the rudder, but I'm not sure where to start. Can you tell me what's important to know about the 6/4 quartersawn mahogany. I'm not even sure where to find this wood. Please let me know some hints about finding and working with this wood.
Thank you,
Miro.

[c_amos]

Thank you Bill for merging this thread into the other one...

WRT the rudder in post #329. These rudders are misunderstood. The assumption (as I might have made) was that the planks seeming to separate indicates failure. The fact is that you can go out and buy the most beautiful new components and assemble your rudder... and if you build it out of wood it is going to wind up looking just like the one you remove.

The mahogany planks are drilled through, and a 'sintered' bronze rod has been placed lengthwise through the socket. This is a pretty sound construction method. Now, after the boat has been in the water and water has gotten into the grain of the wood it starts to do what it did when it was in the woods and surrounded by it's friends.... it absorbs water and swells into a wonderful solid unit.

The problem comes when we haul the boat, and the rudder starts to dry. The planks get gaps in them which we long to fill (I know, I did). Some construct elaborate systems of straps or fiberglass coatings to ensure the planks will stay together.....

They (mostly) stay together on their own anyway.

Wow, I am getting long winded here.

You can make your own out of fiberglass. Make sure not to put too fine of a trailing edge on it. First it is not necessarily as hydrodynamic, but second the fine edge produces a turbulence that WILL make your rudder / tiller hum and vibrate.

Keith did an absolutely masterful job with the rudder on Ariel Spirit (Hull #3) (I believe you will find it mentioned earlier in this thread). When my wife and I delivered her from MD to NC we found that the rudder would hum and lightly vibrate near 5 knots.... not a terrible issue, but I would not have chosen this... especially given the miles we have sailed our little ship.

Yes, in this long and rambling post I need to get to my point.

On Faith's last haul out (pre-cruise) we removed the sealant from between the planks, we fared some of the trailing edge with epoxy, then we filled the gaps back in with a bead of 3M 5200 that was then scraped so as to produce a thin 'link' between the boards.

THis is tough to describe, but basically we wanted to fill and secure the planks but also allow them to swell when the hull was splashed. I wish I had taken some close up pictures, but picture filling in the gaps and then removing and smoothing the sealant with 'valleys' between the planks. That way the sealant was adhering to the edges, but not completely filing the void.



I can type more on this if it is helpful... I suspect I may have typed too much already.

I will say that I did dive and scrub (caress?) the rudder often since.. and have not found any weakness. I will likely do a haul out after the oil spill clears and will update things then.

[Commander 147]

As you can see our hard working forum administrator has merged this thread with the main one on the topic. And because of it there is probably a lot more information here now than you will be able to read in even a couple of sittings.

But to answer the specific questions you asked me, and since I don't know how much you already know or not I will go into detail. I'm sorry if I am wasting your time telling you things you already know.

I decided to use quartersawn mahogany because it is much more stable than flat sawn mahogany. Most people know that wood shrinks and expands as it takes on and gives off moisture. What many people do not know is that the amount of movement varies based on the orientation to the growth rings. For example, for all practical purposes wood will not shrink or expand in its length. While not 100% true the amount of change is so small it usually is not worth considering.

Take a look at the drawing below. If you were looking at the end of a log that was being cut into lumber you can see the boards I have labeled as flat sawn have a different orientation to the growth rings than the boards I have labeled as quartersawn. The growth rings are for the most part perpendicular to the face of the board in the quartersawn boards and they run more parallel to the face of the board in the flat sawn. Flat sawn boards will shrink and expand almost twice what a quartersawn board will. In addition because of the orientation of the growth rings they will tend to cup and warp much more than quartersawn boards.

To illustrate my point you could expect an 8" wide flat sawn board to expand by .05" when it goes from 8% moisture content (a good level for furniture building) to 28% (saturation point) while a quartersawn board would only expand by .03".

As far as where to buy the material that depends on where you live. Some parts of the country have much better access to lumber than others. I would look first in the yellow pages for hardwood lumber retailers. Then call cabinet shops in the area if you cannot locate anyone you can buy from direct. They will often sell you what you need with a small markup for their trouble. And if all else fails do like I did and search on the web.

[Miro]

Jerry,

Thank you very much for all the information you've provided. It is all very helpful. I hope to get started on this project soon, but I'll take a little time to digest all the details first.

Miro.

[ebb]

Original Ariel/Commander rudders lasted 45 years (so far!) as two relatively unprotected planks of brown wood under water.

You want Honduras Mahogany (swietenia macroplylla) lumber to replace an original rudder.
You need a reputable dealer. Go where furniture and cabinet people go. Don't trust big box.

You want straight grain 5/4 or 1 1/2" lumber to begin with. Any "honduras" you see in a lumber store has had its "quartersawn" pieces culled for veneer and high end furniture before it got there.

However swietenia macrophylla is the MOST STABLE WOOD IN THE WORLD.
You may find boards that have SOME quartersawn characteristics, I would go for those.
But you won't have cupping issues with the correct mahogany and stuff you choose from off center of these huge trees.

Do NOT build your rudder with african, indonesian or philippine "mahogany". These are either punky or snakes or both. These are NOT mahogany.
Use a substitute (spanish cedar, orange wood, locust, yellow pine, etc.) at your peril.


Use ALL SILICON BRONZE rod, allthread, bolts, lags, screws. NO stainless steel.
If you replicate the original rudder, yours will last another 45 years under water!!!!

[Commander 147]

ebb

I agree Honduras mahogany is the correct material to use. But I think lumping African mahogany in with indonesian and phillippine is a bit harsh treatment for African mahogany. Khaya spp. (it's scientific name) and it's close cousins Khaya anthotheca, K. grandifoliola, K. ivorensis, K. senegalensis which are all brought into this country under the name African Mahogany are used all over in boat building. Just about every wood database you can find lists boat building as one of the primary uses for African mahogany. Here is a good example.

http://www.wood-database.com/lumber-...ican-mahogany/

[carl291]

I purchased two Honduras mahogany boards and cut out a rudder. This wood seems very light (soft) and dry compared to the two African mahogany boards I also have. The reason I bought the A. mahogany was because the H. Mahogany seemed to feel like a soft wood while the A mahogany had a heavy and very oily feel.
I took a scrap of the H mahogany and threw it in a low wet spot in the pasture last summer and it has been lying in the water and sunlight for about 11 months. I assumed it would be absorbing moisture and begin to decay however other than some color fading from sunlight it appears to have picked up little to no moisture that I can determine. This wood has surprised me, now I'm confused as to which would make the best rudder.
Both of these woods were purchased on EBAY from Sergio exotic woods in Miami, Fl Also, Jerry thanks for explaining quartersawn.

[Miro]

Thank you very much! I'm having trouble finding a source for mahogany in New England. I'm from Connecticut. I haven't found any suppliers through eBay yet. Maybe one of you knows a good one??
Miro.

[Miro]

[Commander 147]

Miro

These guys may not be within a short drive but they can UPS the material to you.

http://www.hearnehardwoods.com/hardw...gany_wood.html

[mbd]

I've seen these folks recommended quite a few times: http://www.mainecoastlumber.com/hard...d-lumber.shtml

[bill@ariel231]

I also had good luck getting mahogany for a rebuild of our vintage dyer dink from boulter plywood in Somerville, MA http://www.boulterplywood.com/.

good luck, sourcing material is getting hard

[Chance]

Here's a question I'd like feeback on:

In regards to the rudder shaft strap (Gudgeon), why don't you see them on the rudders of the following vessels:
Morris 28
Bristol 27, 32 (first generation)
Cape Dory 28 (perhaps the 25, 26 and 27 as well)
Sea Sprite 28

All the above have keel hung rudders, and some are not even a one piece shaft.

What are your thoughts?

Ebb? I know our beloved vessels have them. Could this strap be unique to how our "original" rudders were made? Pearson didn't build composite rudders on ours, if they had, do you think they would have found it necessary to add the strap?

I ask your input, as I'm not building an original configuration but rather a new composite, cored, sheathed and the likes.