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Old 22-02-2021, 17:05   #31
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Re: Need Advice to Complete My Steel Rudder

We have a local fab shop bend/roll our artwork all the time. Butterfly benches made out of 3/16" and 1/4" mild steel, and 304SS, horses out of 1/4" Corten steel, etc. Between the electric/hydraulic roller, and their 16' press, easy peasy. Shop cost is pennies vs screwing around for days running over with tractor, etc. I WOULD make the pieces slightly over sized though. Easy enough to trim off excess.

Are you using 304 or 316? Good luck!
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Old 22-02-2021, 17:50   #32
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Re: Need Advice to Complete My Steel Rudder

you can buy eye pads off the shelf, which is just the metal " eye" formed over a small pad...there is no " bolt". you weld the pad to the steel. voila. done. no drilling, but a bent over rod will do just as nicely.
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Old 22-02-2021, 20:57   #33
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Re: Need Advice to Complete My Steel Rudder

MicHughV has got it right. He built a steel boat so it is experience talking. I built mine also, 42'. You do not need to do any prebending. And you certainly don't need to wrap the plate around the leading edge. As MicHughV said, tack both plates onto the leading edge tube, intersecting it at the angle that they should. Then clamp both plates and bring them back.

As the plates pull in you can reach thru the opening at the aft end to make some welds to your ribs. You don't need much there. Intermittent welds to the ribs will keep the plates following the rib contour as you continue to pull them in with the clamps. The rudder would be OK without these intermittent welds to the ribs but what might happen is that the plate might pull away from some sections of the ribs as you clamp it in, changing your foil shape a little.

The plate will pull in well because of the leverage you have on it. And - and this is a big deal - the stresses on both sides will be equal and opposite so the rudder will not twist or deform.

Note - when welding the plates to the leading edge tube make a short - not over 4" max weld on one side, then make the same weld on the opposite side plate. Go back and forth this way. This equalizes weld shrinkage strains on both sides and keeps the leading edge straight. Ditto with welding the rudder shaft in. Weld shrinkage is a powerful force and can distort things if not managed correctly.

You're going to find that this will work out well. And there is no reason to fill it with oil. Weld in an 1/8" female pipe stub (I forget what they're called) and when done with the rudder pressurize it to a LOW pressure - 3 PSI is good. Use bubble solution on the welds, find any leaks and weld them closed. The hermetically sealed rudder cannot rust inside, there is not enough oxygen in there to enable any significant rust formation. If you put that pipe stub on the bottom you can, in the future, unscrew the plug from it if you want to verify that it hasn't leaked.
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Old 22-02-2021, 23:40   #34
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Re: Need Advice to Complete My Steel Rudder

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Originally Posted by raahell View Post
Thanks DiSailor,

Yes I've been thinking it'd be a good idea to have something at the trailing edge to tie lines to in case of steering gear failure. Also good to secure the rudder if I ever have to remove it when the boat is in the water. I had to do that on my first sailboat.

I would probably not use eye bolts but just bend some SS rod to a U and weld it in place. The fewer holes in the rudder the better.
Or put a threaded sleeve right through and put socketted plugs in the ends. Nothing sticking out and you can remove the plugs and screw in some eyes of you need to attach lines.

I must have cut a ton of extraneous steel out of mine over the years and it should be a criminal offense to put stringers in a steel boat.
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Old 23-02-2021, 14:33   #35
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Re: Need Advice to Complete My Steel Rudder

I'm not sure I understand the concern about getting water inside the rudder.

This is no more a concern that worrying about getting water inside the hull.

The welds should make it airtight, after which it will get slathered in several coats of paint, sealing any possible micro hole anywhere.

I removed my steel rudder after about 10 years in use. I could detect no water inside. None...zip...nada..I flopped the rudder over this way and that to see if I could hear or feel any water...nothing !

Here's a thing about rust....speaking as a retired structural engineer, I can tell you that a piece of steel plate can throw of a tremendous amount of rust. Visually, it can look alarming, but still structurally sound.

It's easy to measure. You can buy a metal thickness gauge on Amazon, there is a huge variety to pick from. $2-300 will get you a good one. You just press the little foot against the steel, and it will read out the thickness....fractions of an inch....mm....

You can spot check an entire steel hull in a day.

The big concern is always rusting from the interior where you can't see it. Here is where the gauge comes handy. If the gauge shows a suspect area on the outside, you can " sound" the area every few inches to determine the extent....if any...it can also direct you where to look on the inside.

Finally, with today's modern coatings, visible rust is easy to fix, repair, repaint, etc.

Interestingly enough, after I sand-blasted and painted the interior of my boat, I discovered a place I had missed. probably about 12" wide x 3' long, under a cockpit seat. I did not have any more paint, so I slathered it with West System Epoxy and it worked as good as the coal-tar epoxy. never a single rusting issue there.
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Old 23-02-2021, 15:03   #36
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Re: Need Advice to Complete My Steel Rudder

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Originally Posted by BlueH2Obound View Post
We have a local fab shop bend/roll our artwork all the time. Butterfly benches made out of 3/16" and 1/4" mild steel, and 304SS, horses out of 1/4" Corten steel, etc. Between the electric/hydraulic roller, and their 16' press, easy peasy. Shop cost is pennies vs screwing around for days running over with tractor, etc. I WOULD make the pieces slightly over sized though. Easy enough to trim off excess.

Are you using 304 or 316? Good luck!
Wish you were nearby. I'd drop by with my pieces.

The rudder is being made of regular carbon steel W44, not stainless.

The skins are already cut and I do have a bit of excess on all sides.
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Old 23-02-2021, 15:23   #37
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Re: Need Advice to Complete My Steel Rudder

Hi MicHughV et al:

I already have an ultrasonic thickness gauge (only paid $80 for a barely used one) and have been using it on questionable areas. It might be the best investment I could make in terms of maintaining the boat's integrity.

OK I'm going off the rudder build topic here but I see some are writing about worries of water inside a steel assembly. Hopefully it never happens given care in original build and regular maintenance. But it does happen from time to time. Example: my swing keel which had suffered some corrosion due to coating failure (below pic).
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So I removed it, removed the drain plug and it was 1/2 full of a water/oil mixture! Using a compressor, I found some small holes in a weld area around the pivot tube. Used the ultrasonic gauge to determine thicknesses there and some other suspect areas, added weld beads accordingly and now she's airtight once more and looks like this.

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Ready for her new coatings. I'm using some West System epoxy with coloidal silica to fair it off a bit, then commercial Amercoat products for priming and painting. Just need to wait for some warm weather...
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Old 24-02-2021, 10:31   #38
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Re: Need Advice to Complete My Steel Rudder

More stuff.


Please look at vesconite.com for rudder bearings. You can not get better material.
42 years life on mine so far.



My SS rudder shaft ends in a radius crown at the bottom. In the lower foot bearing, there is a similar crowned disc. The two meet at a small point. Its like a jewel bearing, no friction.

I have a split chain link welded to the outside top of the rudder for attaching two pre-sized lines with caribiners to the cockpit secondary winches as a second emergency steering solution.


I would still fill with oil, to make it immune to pressure, ambient changes, and to prevent lifting. If oil comes in at .086 and seawater at 1.12 the bearing is carrying a light load.
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