How Do I Fix a Bent Rudder Post?

[Stumble]

Originally Posted by tkeithlu

What happens if you heat, straighten, and anneal stainless steel? Does it lose the work hardening the same way ordinary 1020 steel does?

To anneal stainless you have to heat it past 1050C and hold it there for I think about an hour. Try this with a fiberglass rudder attached and the heat will destroy the laminate. Because epoxy breaks down at around 120C.

But it isn't just the mechanical properties that are a problem, once work hardened, stainless becomes highly suceptable to SCC (stress crack corrosion).

So ether way you are in trouble. Leave it the way it is and the post has debatable mechanical properties and will corrode much faster than good condition metal. Try and anneal it and the fiberglass is ruined.

If you are day sailing in protected water, I guess you can just see. But I would never trust it.

[tkeithlu]

Sounds like replacement is the only fully trustworthy repair, particularly if you're going where the boat was designed to go. Makes me extra thankful that my rudder is protected by the keel and a foot. I see a fair number of bent spade rudders in the yard. Nice to have the lowest parts really solid.

[SailingFan]

Well, on my Hunter 27 (1978), I discussed this with the yard manager, who regularly sails competitively here on the St Johns River, and he told me that he was the first monohull racer to win the Cup Race here, and his sailboat had a bent rudder that looked almost exactly like mine, with the exception that his skeg went farther back, and he had to cut about 3" off the rudder top portion and epoxy it closed to retain waterproofing.

He told me that the white material in the picture I listed here is likely the gelcoat on the inside of the hull so I was wise to consider rebuilding the thickness of the skeg above the damaged rudder (as illustrated in my photos earlier in this thread) with epoxy and glass reinforcement, but that I should use some sort of bushing to keep the rudder from floating up (as it tries to float up when we are in the water, definitely not waterlogged!).

He also said that he would not worry about outright replacement yet, unless things changed from how they appeared at the moment, and that replacement would run perhaps $2K for the rudder and post. He also told me of a couple machine shops around that could straighten the shaft. I actually have some foam here that I could use to fabricate a new rudder (with epoxy and glass as a laminate shell), but I would need to locate a steel pipe for the shaft, and it would have to fit the bearing (which, incidentally, has not appeared to have suffered any damage whatsoever).

In the morning (Saturday) I am going to be painting the hull sides again (second coat of white polyurethane) and probably starting my bottom paint (first coat modified epoxy, then another, then ablative for a topcoat), so I will have to repair that rudder skeg damage (where they meet, and the rudder lifts, it wears on that skeg), and the epoxy I will be adding there should be harder than the fiberglass of the rudder. I will also likely put some epoxy as a seal on the rudder itself (just in case, the PO apparently did the epoxy add on the rudder but not on the boat!), and hopefully it will cure enough that my bottom paint won't affect it or be affected BY it when that goes on tomorrow afternoon! Wish me luck on that one!

Oh, BTW, Bonus is being renamed Equinox. Bonus just was not a great name, and the boat is not the nicest out there, but also is not the worst, so Equinox seems appropriate as the "middle of the road" sort of vessel she is to us! The new name goes on tomorrow!

[tkeithlu]

Enjoy the champagne and the repaired rudder. It has been an informative thread for more than just you.

[Sailing Chef]

I know this is old post but how did you repair your rudder? Did you replace it?

[SailingFan]

Sailing Chief, I sent a PM to you about this with my contact information as well.

[james247]

Originally Posted by Stumble

Technically yes it can be straitened, but stainless work hardens worse than almost any metal out there. Which is why it shouldn't be. Something stressed that post past the failure point, and even if you can get it strait again it will be brittle and failure prone.

It isn't the cheap option, but stainless rudders, once bent, should not be restraitened they should be replaced.

1000 percent agree. Same reason keel bolts should be replaced. Stainless is a great product but it has its limitations. It's really hard to sail a boat if the rudder falls off. The bending could easily caused a crack if that's the case it might take a week a month or several years for the crack to fail completely.