Rudder Post Failure?

[catawbahunter]

I've been trying to find the source of a water leak on our 2006 Hunter 36 for some time and recently removed the cockpit floor panel that provides access for the emergency tiller. These pictures show what I found which is a crack approximately half way around the top of the rudder post where you would insert the emergency tiller. This crack has allowed water to drip down onto the fiberglass head liner instead the aft cabin where it would run over to corner on the port side of the boat. From there, it ran down into the bilge. I'm wondering if welding this crack would be enough and welcome comments and possible solutions.

Thanks!

 

[rgranger]

Is it steel? Aluminum?

Can you find a welder willing to weld it on the boat?

 

[JamesG161]

That highly suggests a big impact on your rudder.
You need to check your rudder bearings.
___
Temporary fix to the leaking is some simple boat caulking.
Jim...

 

[catawbahunter]

I believe the metal is aluminum and I'm not aware of any impact. I'm the boat's second owner and the leak has been present for the three years that we've owned the boat. I've caulked the crack to prevent any more water from intruding but I'm now concerned with how to effect repairs. I've emailed Marlow-Hunter and asked for help.

 

[JamesG161]

I've emailed Marlow-Hunter and asked for help.

There are sometimes available the original shop drawing for every Hunter. I don't have the link. I have my shop drawings.
_____
If you can dive your boat, you can check the Play in the rudder bearings, by moving side to side and fore and aft.
There should be very little Play.
Jim...

 

[catawbahunter]

Jim,
Since we keep the boat on the hard for 7 months of the year, I inspect the rudder each year before launching and haven't noticed any problems.

 

[dLj]

I'd suggest when you have the boat out of the water, you grind open those crack so you have good access. Then I'd use West Systems G/flex 655 epoxy filler to fill that joint. Should make a permanent fix, that's a really excellent epoxy for what you need there.

dj

 

[rgranger]

I'd suggest when you have the boat out of the water, you grind open those crack so you have good access. Then I'd use West Systems G/flex 655 epoxy filler to fill that joint. Should make a permanent fix, that's a really excellent epoxy for what you need there.

dj

I was thinking JB Weld but then thought a real weld would probably be better. Maybe an epoxy fix and "keep an eye one it" is an okay way to go?

 

[dLj]

I was thinking JB Weld but then thought a real weld would probably be better. Maybe an epoxy fix and "keep an eye one it" is an okay way to go?

jB weld is a good product, I've used it in a number of applications, but in this case I rather use a more specialized epoxy that has published mechanical properties. The West system product I mentioned is rated for under water applications and has defined mechanical properties that are aimed at these kinds of applications.

JB weld may have defined mechanical properties, but I haven't seen them published. Maybe I haven't looked enough, but having used West System products for decades, I have always seen those products to always meet or exceed their published values. So I am clearly biased in favor of West System products, and am not ashamed to admit it! LOL (I have no vested interest in West System, but I have used their products for decades.)

I would have a lot of confidence in using a good epoxy in this application. That being said, you have to do the preparation work correctly.

dj

 

[dLj]

One other point I should make regarding rewelding. If I were seriously considering rewelding, I would want to know the aluminum alloys used in the original structure, the tube alloy, the plate it's welded into and what was the filler metal used in the original weld. It might difficult to know all three of those base metals. Once knowing all three of those materials, I'd also want to know if there is a polymer bearing inside that tube. I would not want the heat of welding to degrade that bearing. I think the preparation for rewelding would be a lot more work than the preparation for using an epoxy filler.

It was circumferential weld, those are difficult to do and are prone to circumferential stresses. Those can be difficult to eliminate. I honestly think the epoxy fix is the best option given given all the constraints in fixing the rudder support. Of course, I am not there, I can't see it all, but that's my impression given what's been posted.

Just my 2 cents worth...

dj

 

[sailnoproblem]

I agree with dLj with the use of epoxy. My guess is that the cracked area is a aluminum casting, most likely made in China.
You may have a hard time finding a mobile welder that will do the job. Gaining access to prep the area and position to weld would be difficult.

 

[catawbahunter]

Guys... I really appreciate the suggestions and like the idea of using a proven epoxy to avoid all of the concerns mentioned above with welding, let alone finding a person that could do the job.
Thanks!

 

[dlochner]

I'm not familiar with how Hunter built their boats, so I may be off base here. The crack does not appear to be in the rudder post, it looks more like the rudder bearing or the tube the rudder bearing sits in has broken loose from the hull.

If this were my boat, after haul out, I would drop the rudder and inspect the rudder post. Then I would clean up all the gelcoat/paint around the crack and see what's there. Getting a copy of the original shop drawings would be helpful.

The rudder tube and bearing assembly is not something to mess around with. JB Weld would not be my product of choice. It may be fine for other applications but this is not one of them.

Since the joint has broken, it means one of two things, the joint was subjected to some kind of trauma, like a rock, or it was under built in the first place. Get the rudder out, clean up the area to see what you have and send us new photos.

 

[catawbahunter]

I agree. It’s not the post itself but appears to be a flange at the top of the rudder tube. Still no word from Marlow-Hunter. Drawings would be helpful.

 

[dLj]

I'm not familiar with how Hunter built their boats, so I may be off base here. The crack does not appear to be in the rudder post, it looks more like the rudder bearing or the tube the rudder bearing sits in has broken loose from the hull.

Yes, the question is what are the materials on each side of that crack? But if you look carefully at the photos, it appears both sides of that crack may be the same material. But you may well be right, could be one side is fiberglass.

If this were my boat, after haul out, I would drop the rudder and inspect the rudder post. Then I would clean up all the gelcoat/paint around the crack and see what's there. Getting a copy of the original shop drawings would be helpful.

I definitely agree with you here on several points, but I'm not sure I'd drop the rudder first.Shop drawings would be really useful! The problem in my mind w.r.t. dropping the rudder first thing, is currently everything is in alignment. If you can get everything cleaned around that, open up the cracks so you can then fill with epoxy, you'd keep everything aligned. Then you could drop the rudder and inspect everything else, like the lower bearing surface, rudder etc. It seems to me if you dropped the rudder first, you'd have a job making sure the bearings are all aligned in reconstruction. Now, I'm assuming this has a top and bottom bearing.

The rudder tube and bearing assembly is not something to mess around with. JB Weld would not be my product of choice. It may be fine for other applications but this is not one of them.

+1!!!

Since the joint has broken, it means one of two things, the joint was subjected to some kind of trauma, like a rock, or it was under built in the first place. Get the rudder out, clean up the area to see what you have and send us new photos.

It may also be a poor weld joint; bad weld, incorrect filler material, residual stresses during welding, etc. That is, if the bottom side of that crack is also aluminum. Images 4 , 5 and 6 sure seem like aluminum on both sides of that crack.

If it is fiberglass, then what broke? How did they adhere this aluminum to the fiberglass? I would be skeptical it was under designed, unless that is the only bearing and there is not another one lower down. Then you would be spot on!

dj

 

[dlochner]

What vintage Hunter 36? Does it have a skeg hung rudder?

Using just epoxy to fill the crack is probably not a good choice. That cures the symptom (cracked rudder tube) but does not solve the problem. Epoxy is strong, but very brittle unless there is adequate filler/cloth/fibers in the epoxy. Squirting thickened epoxy into the crack is not a long term fix.

Welding the part while in the boat is probably not a good option. The heat from the weld will damage the glass. Again, I'm not a welding expert, however, I have been told that a weld in cast aluminum is not as strong as a weld in machined aluminum. I wasted some money once having a cast aluminum bow chock welded.

Aligning the rudder tube after removing the rudder and parts can be tedious. It would be possible to build a simple jig to align the tube after the rudder is removed and before the bearings are removed. Use a piece of PVC pipe, probably 2" diameter to align everything and a wood frame to center it.

 

[NYSail]

Drop the rudder, disassemble the "arm" and scrape and clean the entire area...... then conclude what to use but I do agree with above posts regarding quality epoxy. At this point you will also be able to inspect the bearing.

Good Luck

Greg

 

[dLj]

Let me begin by saying I very much appreciate your comments/input. In the world of these kinds of forums, there is little emotion transmitted, so please interpret all comments as a friendly dialog.

Using just epoxy to fill the crack is probably not a good choice. That cures the symptom (cracked rudder tube) but does not solve the problem. Epoxy is strong, but very brittle unless there is adequate filler/cloth/fibers in the epoxy. Squirting thickened epoxy into the crack is not a long term fix.

Well, it depends upon the root cause of the current cracked tube. If it was a poor weld then the epoxy fix may be excellent and permanent fix. To be sure, I did not recommend just any epoxy, but rather the G/flex 655 product. Just squirting it in is also not recommended, but rather proper preparation is mandatory. The G/flex epoxy is not brittle, it has 32% elongation in tensile. That's not a brittle material. Below find a short description of this product. You can look it up on the web and get all the technical data.

A toughened, versatile epoxy that is conveniently pre-thickened for permanent waterproof bonding of plastic, fiberglass, ceramics, metals, damp and difficult-to-bond woods. With a modulus of elasticity of 150,000 PSI, it is a bit more flexible than standard epoxies and polyester, but much stiffer than adhesive sealants. This gives G/flex 655 the ability to make structural bonds that can absorb the stress of expansion, contraction, shock, and vibration. It is ideal for bonding dissimilar materials.

Welding the part while in the boat is probably not a good option. The heat from the weld will damage the glass. Again, I'm not a welding expert, however, I have been told that a weld in cast aluminum is not as strong as a weld in machined aluminum. I wasted some money once having a cast aluminum bow chock welded.

If welding were required in this case, I likely would not reuse the part. I would build a replacement part. In regards to welding aluminum, it really depends upon the alloy. Cast or wrought is not the main concern but rather the specific alloy itself, and then how it is being welded, heat input and with what filler metal. Incorrect selection of filler metal can lead to embrittlement and increase the risk of corrosion failure. Adhesive bonding of aluminum is frequently done in industry. Always with aluminum alloys, surface preparation, especially in adhesive bonding is highly critical.

Aligning the rudder tube after removing the rudder and parts can be tedious. It would be possible to build a simple jig to align the tube after the rudder is removed and before the bearings are removed. Use a piece of PVC pipe, probably 2" diameter to align everything and a wood frame to center it.

This tedious alignment process is what I'd like to avoid if it was my boat...

dj

 

[Ken Cross]

I'm surprised no one told you to have someone push and pull on the rudder while you watch the crack. Assuming you are on the hard. This may hint at whether or not this is a structural problem.

Ken

 

[isaksp00]

I'd be concerned about the stress from the forces on the rudder against the tube, given what appears to be the cast support piece is cracked for around or over half the diameter. Ideally you'd replace that piece, but that may not be feasible. Can you inspect it from the bottom to get an idea of how compromised it is?
In any case I would not simply epoxy the crack. After using something like the West system epoxy to strengthen the cracks, I'd reinforce the tube structure with biaxial cloth. A few layers above the casting, wider than the diameter of the cast piece, and gusseted up against the outside of the tube above the casting to provide sideways support to the tube. That would also seal the leak. Of course, clean off all the loose epoxy first, and grind down to expose the epoxied structure that forms the floor there.