Rudder inspection or replacement?

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lauraj
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Rudder inspection or replacement?

Postby lauraj » Mon May 12, 2014 8:42 pm

Our new to us boat is 25yrs old (#8) and the rudders have presumably never been inspected. We do know that one had a bent shaft about 5 years ago and that the fix was "adequate".

There is no indication of damage, but one does drip rusty water when held upside down, (yes, they have been removed) so we are assuming that there may be internal issues.

Does anyone know of how we should go about inspecting for internal damage without opening it up?
Anyone know of a company in the New England area that does this?
Is this a part that may be nearing the end of life expectancy and we should just look to rebuild or replace?
Suggestions please!

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Page 83
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Re: Rudder inspection or replacement?

Postby Page 83 » Sat May 17, 2014 10:22 pm

Shake it. Does anything rattle?
No? Put it back in the boat and sail until it falls out.
Yes? see "No."

There are only a few commercial grades of Stainless Steel that seriously resist rust, and they are all softer that what is needed for a rudder.
The metal parts of a rudder consist of a shaft and splines that are welded to the shaft and buried in "stuff" inside a hollow fiberglass rudder.

There's one thing bad about Stainless Steel: it corrodes under water because, believe it or not, it needs oxygen to resist, er, oxidizing.

The cure for rudder rust stains is far worse than the social embarrassment of brown stains on your behind(s). It involves cutting windows in the sides of the rudders, and carving out the extremely well cured "stuff" around the splines. If they are still splinely, grind, file, and sand off every spec of rust, replace the "Stuff" and glass over the holes. Or you could just grind the splines off, weld in some new ones (they are likely 304 stainless), and I recommend a TIG welder to get penetration without heat-soaking the shaft and starting a forest fire.

n.b. "Stuff" or "Ickumpuckee" is a peanut-butter-like polymer filler that turns as hard as rock in a few years. It expands and contracts at a different rate than the rudder shaft when the temperature of the water changes. Then the water freezes creating microscopic cracks which suck in microscopic quantities of water (with salt) which freezes, expands and pulls more water in. Bada bean, bada boom.

Ninety percent of all fiberglass sailboats have the same kind of rudder construction. The problem is universal. The solution is the same. However, in a lot of rudders the progress slows down after a while, and the rudder will last 25 years. So, if it doesn't rattle, put it back on!
Sandy Daugherty "Page 83" PDQ 36026

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thinwater
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Re: Rudder inspection or replacement?

Postby thinwater » Sun May 18, 2014 12:03 am

My theory--true or not--is that freezing does most of the damage. The corollary is to never haul a boat for the winter in a freezing climate. I do know that I have had 2 boats over 30 years, never hauled them in winter, and never had trouble. The one year I hauled, unusual snow loads caused some mischief. Thus, I stay in.

A boat that stays in the water does not see subfreezing temperatures in most of the hull structure and certainly nothing below water. Some additional wear and tear, I'm sure, but less trouble from temperature extremes.

Just a though, perhaps not much help up there.
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amytom
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Re: Rudder inspection or replacement?

Postby amytom » Sun May 18, 2014 12:16 am

Another way to prevent the freezing is to sail south.

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Re: Rudder inspection or replacement?

Postby Page 83 » Sun May 18, 2014 2:15 pm

There is a tweak for a rudder that has been bent and de-bent. Its possible that the accident and repair have resulted in a new zero angle of attack. That is the position where the rudder exerts no side-ways thrust. it needs to be set with the boat moving through the water without wash from the engine confusing the issue. This can be accomplished best with the boat under tow at four or five knots, a problem in itself. The idea is to disconnect the rudder from the crossbar, let it trail, see if there is a difference, and reconnect everything. The starboard side has an additional difficulty since the cable quadrant is keyed. The solution here is to steer with the emergency tiller on the port rudder.

and remember, When in doubt, trust James Power!
Sandy Daugherty "Page 83" PDQ 36026

lauraj
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Re: Rudder inspection or replacement?

Postby lauraj » Tue Jun 24, 2014 12:20 am

Follow up. To the best of my knowledge, 24 year old rudders have never seen cold water (never above FL in winter and hopefully never will) :wink:
Not real comfortable with the idea of being in some channel between islands when it decides to fall apart.
Has anyone every tried resistance (moisture) readings on a known good to compare to a suspected bad?

as to "trailing" it. when we removed them, the only thing holding it in is was the friction in the bracket from the steering rod.
Can only see bad things from loosening that while in water.

seems like this might be opening a different can of worms. what other parts should be holding port rudder in place?

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Re: Rudder inspection or replacement?

Postby Page 83 » Wed Jul 02, 2014 2:16 pm

Many rudders built this way have positive buoyancy.
Sandy Daugherty "Page 83" PDQ 36026


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