Commander #256 (Ceili)

[Commander 147]

Here's the assembled rudder shaft assembly. Next phase, rudder core fitting.

Wow I don't know how I missed your post yesterday. But I have to agree with Ebb and Ben That the work looks great. I'm very interested in following your progress on this project so please keep us up to date.

[Chance]

Thanks Ebb, Jerry and Ben.

The machinist / fabricator jointed the machined joints via silver brazing (not the same thing as silver soldering) though sometimes in the industry the terms are used interchangeble. It has to do with the temperature of application, in this case above 800 degrees.

I decided to modify my original drawings and added the two flat bars for peace of mind that the rudder foil (core) would not be able to slid off the rods. I know, this whole thing will be epoxied togetger before ever getting to sheathing it in glass, but in my mind I kept thinking that without the flat stock, the only thing holding the rudder foil to the bronze skeletol structure wold be epoxy. So...for peace of mind the flat stock was added to satisfy my mind a wandering.

Last night I began the tedious process of laying out the lines on the inside face of the core. Much like working with a book opened up, two mirror halves that have to be milled to accept the bronze rudder stock assembly.

I'll post photos as work progresses.

Thanks gents.

[Chance]

Today I managed to to "let in" the bronze skeletal (thanks Ebb) to the core halves.
Here's what it ended up looking like:

[Ariel 109]

When I saw your metalwork Chance I wasn't too sure about how brazing would hold up in the marine environment. But after reading about brazing practices online I find out it's commonly done.

Is that the final shape of your rudder? Are you going to add some curves unto the trailing edge?

Your work is really beautiful, all of your attention to details is a joy to follow.

Ben

[Chance]

Ben,
Thank you for the kind feedback. In response to your questions:

1) The pictures I have posted thus far do not reveal the "final" rudder profile...well it is close to the final however I still have some work do do before the final profile becomes evident, prior to the glass work.

2) Yes, the "final" profile will have the rounded corner on the lower, aft trailing point of the rudder foil. The core you see now has been reduced in size to account for the following allowances: a trailing edge that will add an additional 1" to the for/aft measurement, as well as 1/4" allowance for glass work.

You can barely make it out, but on the aft edge of the core, I milled a rabbet that will accept (receive) the final component: 1/8" X 2" aluminum flat bar that will run the length of the rudder aft edge. I choose this method to accomodate the narrow (width) profile I aim to achieve upon glass lay up, 3/8". For my peace of mind, I thought that having only 1/8" wood core at the trailing edge would be too weak and it would be difficult to conduct my final foil shape if I had to bring each half down to 1/16" on the trailing edge. The aluminum buys me a bit of breathing room and will add to the rigidity and strength of the rudder's trailing sector, without inducing much in weight. Forthcoming photos will depict this much more clearer than I can describe, so enough of me rambling.

Thank you.

[Commander 147]

Ahhh Ha

So that is what that rabbet is all about. I saw it but had no idea why you had done it. Thanks for filling in the blank for me. :-)

Enjoying the progress so far.

[ebb]

Chance, It's amazing and gratifying how we all approach things, and especially this rudder, from different angles.
I have stubby flat plates, forinstance, in three positions each welded into a narrow triangle that comes off a full length shaft from the back third of its circumference.

I'm making a constellation rudder like you are from the same palimpsest pattern Alberg drew on his original lines drawing. I think the only change I made was to tilt the bottom of the blade up an inch at the trailing edge. And I may have a smaller round than what the master has.

Will certainly have foil shape sides. But only half foil since the rudder's front half of the foil is the keel itself. To my way of thinking.
I'm also fattening up the rudder at the keelpost because I think the transition from the keel to the rudder should not step down, but be as fair as possible. That's a can of worms because the rudder shaft is set in to house the original 1" wide wooden rudder we had. A wider rudder can't turn to the angles we need, not only for steering, but to move and remount the rudder when needed.
So while there won't be a step, there will be a space to allow the wide turning angle.

My method was/is to have a center plate of fiberglass laminate that is the shape of the finished rudder in profile. Then I intend to add divinycell foam to the sides of that panel - carve and shape the foil and cover with plain or fancy (kevlar) cloth. Will have to take a couple turns around the shaft to encapsulate. But don't expect water intrusion to ever become a problem.

One of the most clever ideas I've ever seen for insuring that the halves of a rudder stay together was to drill strategic holes thru the blade with a HOLESAW. Then fiberglass thru the holes with fabric strips opposite skin to opposite skin, glue back the doughnut, fair it, and finish with a last layer of glass.
Do this in way of the armature and the rudder will never fail!

Intend to take my trailing edge back to a 1/4" thickness, about the thickness of the center plate, and square it off sharply to break suction.
That long STRAIGHT edge of this style rudder compared with the rounded sure is intriguing, isn't it?

Don't know of anybody who sails a Commander or Areil with one. It's about time! CAN'T WAIT!!!!

[Chance]

My mind is a wandering...

Ebb, Thanks for the most useful insight and once again, more ideas and fresh looks will aide in my course of action as I progress. I too, had thought of way to ensure the halves stay married together but the wholesaw method is something I never would have thought of. I had thought of using stategically placed bronze wood screws, leaving them in and glassing over, or doing nothing and relying solely on the epoxy.

I too, find it most interesting how varried the approaches can be for us "stewards" to seek and progress in reviving out beloved craft, satisfying our talents, pushing the envelope of creativity and easing peace of mind. So many very, very talented, mastery skillful and just plum amazing works demonstrated on this forum. It's a true pleasure to continue to admire and follow progress of the varied challenges we all face.

You hit on an area, I too, have been contemplating: How to increase the thickness of the leading edge of the rudder foil, without compromising the port/stbd turning sweep. Ebb, what is your final thickness to aim to achieve at the leading edge of the foil, just aft of the shaft itself? I was thinking in line of 1-1/4", but have considered as much as 1-1/2". Have you nailed down a final dimension, or did you already finish your constellation style rudder?

Now, if only I was sailing like Ben, up North and so many others! Jerry, where's the cooler air? I'm tired of the mid to upper 90's with heat indexes in the triple digits. By the way, your installed cabinetry is first class all the way!

[ebb]

Chance,
I messed with the 'keelpost' of A338.
Naturally found the back end of the boat unsymetrical and hollow - so filled & faired it straight - and fattened it up. Worked the cove with sanding sleeves until the gelcoat was gone.
Was influenced by the original scantlings in the same set of Alberg drawings - I believe the keel is two inches wide at the cove where the rudder is mounted. Total, that includes the 1/4" flats on either side of the cove.
Spent too much time and epoxy fairing this socalled keelpost area and making it even and straight from where it leaves the bottom of the hull down to the heel fitting.

I was shocked that Alberg showed a fatter rudder in the plan view of the heel fitting. He shows an 1 1/2" shaft. It meant that the beautiful mahogany and bronze rudder Pearson choose to use - because it was thinner by half, ONE INCH wide rather tham 2"...had to be mounted further inboard.
When we make a simple paper model of the as built 'hinge' effect, the 1" wide rudder swings perfectly.
When we fatten the thickness of the rudder and use the same bearing in the heel fitting, it becomes obvious that either the cove of the keelpost has to be carved back to much less of a cove. Or the fatter rudder itself has to have its radius carved into more of an oval shape to get the swing needed. The swing neeeded matches the swing we have in the cockpit with the tiller.
Can't be anything less. And might have to be more, close as we can get to 80 degrees, which we can't do of course because of what we have. But we need that radical angle to ease the rudder out of its tube and past the heelfitting when we drop it. And when we put it back in.

Made various 1" dowel and doorskin models of failed rudder ideas. Kept one model so to try the fatness of the finished rudder. I'm on the hard so I can't put the work-in-progress rudder in for test fitting. Have to still use the mock-up when pasteing the final bronze and foam rudder together. The rudder is on my next to do list.

It's easy enough to make a cardboard rep of what you have and using the heelfitting on your boat and the cove in the keel.... figure out how the rudder will swing within the parameters.
Not talking about making a 3D rudder model, just making a 2D cardboard model of the swing on the flat of the keel fitting. Draw the heel fitting exactly as you have it. cut the original 1" wide rudder and with a push pin see how it actually swung on the heel.
Then cut and paste to see what you have to do to make your new rudder scantlings do what the 1" wide rudder could do.

The new rudder isn't going to perform exactly like a copy of an original one. Fattening the rudder at the keelpost comes with a price. We're assuming the rudder that came with the boat worked pretty good but wasn't hydrodynamic enough for sme fools. A beautiful rudder but it had no foil and came to a big fat round trailing edge. We can work in the foil and narrow the trailing edge but the price will be that the flow of water off the keel onto the nice new fat rudder is going to go over (or into) the space we have to leave at the rudder shaft for the rudder to swing properly.
It can be done but it's a compromis.

Have seen thin fairing strips added to the edge of a straight keel like ours that projected over most of the width of the relief space carved into the rudder....in an attempt to add back the hydrodynamic. It's not much, it's do-able. Have to use bronze* gauge sheet metal. And it's another time consuming thing. Do we have to dap the strips into the keel? What are the strips made of? How do we fasten them on? Maybe we're causing more turbulance than solving it?


How fat your rudder... is how it works out for your app. Looks like Alberg was happy enough with a step from the two inch wide keel to a 1 1/2" wide rudder shaft (that never happened.) In our case, if we have to modify the new rudder, it sure would be easier to add a modicum of thickness (with closed cell pvc foam, perhaps) than to grind it away.
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* no bronze available but half hard copper in gauge sizes is available from on-line metals. There are also plastic sheet like mdr nylon or maybe garolite that would prevail under water.

[Chance]

Today, I managed to remove the old rudder and start the initial clean up. I am so very thankful that previous owners DID NOT use any sort of adhesive (like 3M 5200, etc.). After drilling and driving out the copper pins, the strap and rudder shoe came off all so easily. No bedding compound or adhesive had to be fought over.

[Chance]

A few more photos of today's fun.

[ebb]

Amazing, THAT is a look back in time
Nice work Pearson!

[Chance]

Here's today's venture. I joined the two rudder core halves. After the epoxy cures, I'll remove the clamps and chisel out the notch that will provide the opening for the rudder strap. I still have to profile (taper) the core halves, and will make a jig to assist in this, so that each side remains identical to the other.

[Chance]

A couple more close ups.

[Commander 147]

Chance I continue to be impressed with your work. I am even more impressed when I think you are planning on selling Ceili. You are doing such a fine job on the restoration work you are doing that I have a hard time believing you will be able to part with her when she is done.

So tell me, it looks like the halves are made from 12MM meranti which would make the current thickness close to 1" of the new rudder. Do you plan to thicken the rudder directly behind the keelpost to more closely match the thickness of the keel and if so what is your plan of action to do that without limiting the swing of the rudder? It appears in one of your pictures that you put a radius on the forward edge of the Meranti. What is your plan of action for that area? Will you eventually wrap the bronze keelpost with glass or try to seal the point where they come together without wrapping it?

My own thoughts on the thickness of the rudder directly behind the keelpost are that there is a chance we are creating more turbulance than we are trying to eliminate by thickening the rudder there. But it is only a guess and I certainly do not know the answer. The necessary gap between the aft end of the keel and the forward end of the rudder will create a level of turbulance and do we increase it or decrease it by thickening the forward edge of the rudder? Someone smarter than me would need to answer that question for me.