Stress crack on skeg( pic included)

[Manateeman]

If it’s oil you need a different game plan. Epoxy does not stick to oil soaked glass.
After you drop the rudder, grind and post more photos.
No sense in comments until we can see more outside and inside.
Mark

[Rumrace]

Sorry to read about your troubles. I was looking up Dufour builds which are a little vague but there is a possibility the black muck is foam which degraded as the piece delaminated. A rope or a tree branch dragged under and started a compression crack.
I think you should replace the piece completely. Filling it with Epoxy would add to much weight and stress on parts.
If you rebuild it with patches you might consider you might consider a layer of Kevlar roving to strengthen the structure.
There should be a metal web inside and it’s just steel from what I read.

[Spot]

Very small (looking) skeg. If there is rusted steel in there that is an added degree or two of difficulty for a sound repair. I would defer to those who have 'been there and done that'. Some more pictures after sanding would help as Mark mentioned earlier.

[albertjizhang]

Originally Posted by Manateeman

What is that black stuff...Oil? Is there a sump forward of this crack?
Any evidence of a grounding? If you disconnect the steering, does the rudder move evenly? Sand off the antifouling further and look for a old repair.
Stress crack from what stress ? Looks like delamination, this isn’t a chainplate.
We would definitely drop the rudder.
Mark

No it’s not oil, I drained all the moisture out, it’s sea water trapped in it. The black thing seems to be discolored glass, I grounded a very thin layer from the inside and saw that the black layer is very thin, and underneath is intact laminate. However, I’m pretty sure the entire thing being hollow and filled with seawater, the inside of the Skeg is all black, do I have to remove all of them?
I asked the marina, and I can remove the rudder Wednesday.

[Manateeman]

After you get the rudder off, sand / light grind the glass so we can see more. Don’t go crazy grinding. Tap as you go. All you want to do is get back to sound structure. If it sounds hollow, it’s probably delaminated but you don’t want to do damage. Again, more photos will help.
This can be fixed so don’t get discouraged.
Mark

[albertjizhang]

Updates.
The inside of the Skeg is all black, I think it’s just from the sea water trapped in it discoloring the glass, I grounded a very thin layer down and the color went back to normal( as in pic 1) I’m not sure if I can keep the inside layers or not. I’m pretty sure the entire inside of the Skeg is like black like that, but it’s not oil though.

The rudder however, I removed all the screws and **** I can find, but I think the bearing and shaft and knob was built as one unit, and I can’t get the knob off. Anyone has any experience about that?

[double u]

aside remark addressed at all "spade-rudders-are-the-devils, only-skeg-hung-rudders-rule" advocates:
so this is supposed to be the superior design? What holds what, the skeg the rudder or vice-versa?

[Manateeman]

There might be a tapered pin holding things together. One side will be smaller.
Do you see anything like that?

[Manateeman]

I forgot. Did you research this online? Maybe the owners groups can help.
There are parts from International-boat-spares.com which look like your photo.
Mark and crew

[paul2884]

Originally Posted by JPA Cate

Interesting comment, about it being an odd place for a stress crack. That was my thought, too when I first saw it, and went on to wonder about a plain old flaw in the layup, period. Then I decided to let wiser heads reign.

Ann

That was my first thought as well, difficult to be sure but the repair is likely to be the same process anyway.

[Cheechako]

Most skegs are hollow with no core. All though during construction workers will pour unused catalyzed resin and bits of cloth debris in the skeg. That is a strange one and my guess is it may be a factory poorly done layup.

The skeg's function is to support the lower end of the rudder and on most that's the only place it actually is attached to the rudder. As such, it probably functions fine as it is, but you want that repaired to keep water out.

I say it can be done with the rudder on, but of course easier and better if the rudder is removed and the skeg evaluated. Seems it may be thin layup along that vertical line of the skeg. But all you really need to do is to seal and smooth that thin area. (if the forward portion of the skeg is robust) There appears to be what... 3/8"? (1 CM) of gap to work fiberglass cloth through after prep grinding.

Drill a hole low in the skeg to ensure you get all the water out, then fill the hole later.

[Spot]

Albert, did you get that cap off?

If you do not have any more set screws or tapered pins, it may just be a cap covering a flattened piece of shaft small enough to slide through the bearings.

I would put the three screws back on the collar, soak it with some penetraing oil through the center and end holes, stick a couple old screwdrivers or a ball joint 'pickle fork' between the cap and collar, and give it some love taps with a mallet and on the screwdrivers until it starts to move then proceed until it comes off. Make sure the rudder is not going to free-fall if its hinges are undone (!)

If someone with a DuFour or other similar rudder tells you different, consider that advice as well.

Is it just me or does it look like the skeg has been patched before?

[wingssail]

Originally Posted by Spot

Albert, did you get that cap off?

If you do not have any more set screws or tapered pins, it may just be a cap covering a flattened piece of shaft small enough to slide through the bearings.

I would put the three screws back on the collar, soak it with some penetraing oil through the center and end holes, stick a couple old screwdrivers or a ball joint 'pickle fork' between the cap and collar, and give it some love taps with a mallet and on the screwdrivers until it starts to move then proceed until it comes off.

If someone with a DuFour or other similar rudder tells you different, consider that advice as well.

This approach is what I would do but I would use at least three screw drivers (or metal wedges of some sort) so that you could press up equally around the rudder head.

Since you will be pulling up on the whole rudder shaft until it breaks free I would jam wood between the rudder and the bottom of of the boat to prevent its upward movement.

We don't know if the rudder shaft is round or square or has flattened sides. Since there was a bolt or pin going fore and aft which you have removed it is possible that the rudder head, if loosened, would be free to turn independent of the shaft. So another way of breaking it loose is to put the tiller back on, and with the rudder somehow stopped, try to shake the tiller back and forth and possibly free the rudder head that way.

Heat could be applied but the shaft inside the hull should be monitored to make sure that it is not getting too hot to touch which could damage the presumably plastic bearings.

[Searles]

Interesting ,here in OZ 1/2 and full length skegs are common on a lot of older yachts ,I am yet to see one totally hollow ,most if not all are solid with good wood or moulded glass ,but solid to the top and heavily glassed over ,this is a major Component it you steering ,do not skimp on it .⚓️⚓️⛵️

[Spot]

Originally Posted by wingssail

This approach is what I would do but I would use at least three screw drivers (or metal wedges of some sort) so that you could press up equally around the rudder head.

Since you will be pulling up on the whole rudder shaft until it breaks free I would jam wood between the rudder and the bottom of of the boat to prevent its upward movement.

We don't know if the rudder shaft is round or square or has flattened sides. Since there was a bolt or pin going fore and aft which you have removed it is possible that the rudder head, if loosened, would be free to turn independent of the shaft. So another way of breaking it loose is to put the tiller back on, and with the rudder somehow stopped, try to shake the tiller back and forth and possibly free the rudder head that way.

Heat could be applied but the shaft inside the hull should be monitored to make sure that it is not getting too hot to touch which could damage the presumably plastic bearings.

Thanks Wingssail! Better levels of detail and caution in your procedure.