Should I cut my skeg? I've tried everything else...

[demonboy]

We have an issue with our rudder and need to remove it. There's just one problem: it won't budge. The bronze casting on the foot of the skeg was epoxy glued (Kossan epoxy) and bolted on. We've removed the bolts but the casting will not budge one millimeter.

The boat is an Oyster 435 and, as I understand it, apart from the keyway in the stock for the quadrant, there is nothing else preventing this rudder from dropping. There's a bearing in the deck underneath where it comes out for the emergency tiller but I don't see evidence of a circlip at the top or anything else that might be preventing us from dropping the rudder. If anyone knows any different, please let me know! I'd rather embarrass myself with a dumb oversight than attempt to do what I propose next...



This is roughly what the protrusion of the skeg that sits inside the casting looks like, which I believe is fibre and probably part of the original mould:



We've tried everything. We've spent literally hours with a heat gun, being careful not to damage the casting by keeping the gun below 700 degrees. It has melted the epoxy, but we're unsure if this is the epoxy glue or the fin of the skeg itself.

I've managed to gouge out a small channel at the top of the casting and tried using acetone with a syringe. Also, I injected acetone into the bolt holes where there is the smallest gap between the bronze and the skeg. That's done nothing.



We built a 10mm plate that slides into the gap between the skeg and the casting and whacked it with a hammer.

We've tried placing a lever between the top of the rudder and the hull, but all that does is move the entire assembly since the lever is offset from the skeg.

I think the problem we're having is that when the epoxy is heated, it doesn't run but turns to a rubber-like consistency, so it's acting like a rubber glue between the casting and the skeg. I've chisseled and scraped away at the bits I can see but it's not much compared to the parts I can't get to, and I don't think it matters if the casting is hot or at ambient temperature, that epoxy glue is not shifting.

The last thing we're going to attempt is to use some LPG or refrigerant to see if we can crack the epoxy, but honestly, I don't hold out much hope and I think it is time to think of something more drastic: cut the skeg between the gap.

If we did this we could save the casting (removing the crap that's going to be inside it), rout up into the skeg and rebuild it. Since this protrusion was probably part of the original mold and requires a great deal of structural integrity (it holds the rudder in place), sticking some ply and glassing over it may not be enough, so one thought I had was to place a sheet of bronze up into the skeg, glass it in but also bolt it. The protrusion would also be glassed to the correct thickness, following the shape of the casting. It might look something like this:



1. Any further bright ideas on removing the casting before cutting it?
2. Any thoughts on this proposed solution?

We are in Indonesia with limited resources, so brand names of magic solutions won't help, but base chemicals we can get hold of.

TIA

 

[Tradewinds]

What's going on here? Are you certain that there isn't another bronze shoe hidden underneath the grp. I can't see how anything can move if it's being held by the bottom bearing.

Sorry if I've misinterpreted your photos - I'm not familiar with your rudder set up.

 

[billskip]

I may be misunderstanding you but I would think the lower bearing plate has to be removed and drop the whole rudder, I would clean and inspect this area.

 

[billskip]

Trade winds and my post overlapped ...

 

[vyv_cox]

The Sadler 32 has a somewhat similar arrangement. Removal instructions and a sketch here, bottom of the page. Sadler 34 and 32 rudder bearings

 

[demonboy]

@Tradewinds The bronze casting is all one piece, including the bearing that the rudder stock drops in to. If you were fitting the rudder, with the bottom of the rudder removed (this is the sanded patch in my photo), you'd jack the rudder up into place, then slide the casting over the skeg, marrying the bronze protrusion up over the bottom of the rudder stock, creating the bearing. It's simply the steel stock sitting in the bronze casting.

@vyv_cox I understand I need to remove the base of the rudder (the sacrificial wooden block) in order to remove the casting from the rudder, but the rudder has to move up to do this and cannot be done in situ. Meaning the casting has to drop down instead, and that's what I'm unable to do. There is no shoe as per your article that can be unbolted from the casting. The casting is all one piece. Here's a close-up:

 

[billskip]

@Tradewinds The bronze casting is all one piece, including the bearing that the rudder stock drops in to. If you were fitting the rudder, with the bottom of the rudder removed (this is the sanded patch in my photo), you'd jack the rudder up into place, then slide the casting over the skeg, marrying the bronze protrusion up over the bottom of the rudder stock, creating the bearing. It's simply the steel stock sitting in the bronze casting.

@vyv_cox I understand I need to remove the base of the rudder (the sacrificial wooden block) in order to remove the casting from the rudder, but the rudder has to move up to do this and cannot be done in situ. Meaning the casting has to drop down instead, and that's what I'm unable to do. There is no shoe as per your article that can be unbolted from the casting. The casting is all one piece. Here's a close-up:

View attachment 163636

How would you replace the bottom bearing ?

 

[geem]

Have you tried pressing the stock downwards? Forklift truck or something that can impose some vertical load?

 

[demonboy]

How would you replace the bottom bearing ?

We wouldn't replace it. We need to make a bushing for the worn bronze (see Vyv's article).

 

[demonboy]

Have you tried pressing the stock downwards? Forklift truck or something that can impose some vertical load?

No, we haven't. I'm not sure what we could use for this. Also, that would put the load in the wrong place, ie on the bronze bearing part and not the body of the casting.

 

[geem]

No, we haven't. I'm not sure what we could use for this. Also, that would put the load in the wrong place, ie on the bronze bearing part and not the body of the casting.

By vertue of pushing down on the bearing, you push on the bronze casting. It may just need a bit of persuasion

 

[Daydream believer]

Cut the spindle above the bearing then cut the spindle below the bearing. Use a jig saw, or sabre saw, with a metal cutting blade.
Then just lever the bottom half of the shoe outwards. You are never going to push the shoe up & down with the bearing located in a slot.
It is a fair bet that it was fitted by locating on the rudder & swinging into place. Then a pin, or shaft pushed upwards to fix the bearing.
You could get underneath, clean off the crud & have a look for the end of it. Once the shoe is out you can belt it upwards, with a decent drift & cut it off with a grinder, bit by bit.

 

[rogerthebodger]

Could it be that there are some stude holding the bronze casting uo into the bottom of the skeg.

I would use a resiping saw in the gap between the bronze casting and the skeg to see it there are some studs holding the two together.

The side of the skeg could be cut away to reveal the studs if any

 

[bignick]

Could it be that there are some stude holding the bronze casting uo into the bottom of the skeg.

I would use a resiping saw in the gap between the bronze casting and the skeg to see it there are some studs holding the two together.

The side of the skeg could be cut away to reveal the studs if any

My interpretation of the picture in post #6 is that the grp skeg extends inside the bronze casting. That’s the only reason to have the three bolts passing through.

If the bronze casting has been bonded onto the skeg with thickened epoxy then you’ll have a devil of a job removing it, if this is even possible at all!

Thinking radical, could you cut the bronze casting in two, just above the lower pintle and turn the bottom part into a shoe? You’d have to get some machining done so that you could bolt it back together, but at least you could remove and refit it.

Why does it need to come off?

 

[geem]

Have you thought about contacting Holman and Pye for the original drawings of the rudder?

I did the same when I needed the drawings of our rudder. Van de Stadt sent very detailed drawings via email and reasonable cost

 

[rogerthebodger]

This video may help fitting rudder at 6.00

 

[demonboy]

My interpretation of the picture in post #6 is that the grp skeg extends inside the bronze casting. That’s the only reason to have the three bolts passing through.

If the bronze casting has been bonded onto the skeg with thickened epoxy then you’ll have a devil of a job removing it, if this is even possible at all!

Thinking radical, could you cut the bronze casting in two, just above the lower pintle and turn the bottom part into a shoe? You’d have to get some machining done so that you could bolt it back together, but at least you could remove and refit it.

Why does it need to come off?

My interpretation of the picture in post #6 is that the grp skeg extends inside the bronze casting. That’s the only reason to have the three bolts passing through.

This is correct. I can't release the epoxy holding it in place.

Why does it need to come off?

The bronze has worn away so the rudder has lateral movement. It needs a bushing, as per Vyv's article.

could you cut the bronze casting in two, just above the lower pintle and turn the bottom part into a shoe? You’d have to get some machining done so that you could bolt it back together, but at least you could remove and refit it.

My interpretation of the picture in post #6 is that the grp skeg extends inside the bronze casting. That’s the only reason to have the three bolts passing through.

If the bronze casting has been bonded onto the skeg with thickened epoxy then you’ll have a devil of a job removing it, if this is even possible at all!

Thinking radical, could you cut the bronze casting in two, just above the lower pintle and turn the bottom part into a shoe? You’d have to get some machining done so that you could bolt it back together, but at least you could remove and refit it.

Why does it need to come off?

This is correct. The skeg extends into the bronze and was epoxied in place.

It may be possible to cut the bronze where you suggest since it's solid up past the pintle, but because it's solid the shoe would end up becoming very deep and all machining in the remaining bronze would have to be done in situ, upside down (tapping bolt holes etc). Also, because the casting is rounded, there would be no flat surface to drill new bolt holes. One option would be to do away with very bottom of the casting altogether to create a flat shoe like in Vyv's article. The problem with this solution is that now the entire weight of the rudder is relying on those new bolts.

We need to remove the rudder because the bronze pintle is worn and there is lateral movement in the bottom of the rudder. It needs a bushing, again as per Vyv's article.

Apologies for the formatting in my reply. I'm on the phone.

 

[demonboy]

Have you thought about contacting Holman and Pye for the original drawings of the rudder?

I did the same when I needed the drawings of our rudder. Van de Stadt sent very detailed drawings via email and reasonable cost

I have drawings of the rudder and understand how it's all put together. My problem is removing the bronze casting because it's been epoxied into place.

 

[demonboy]

This video may help fitting rudder at 6.00

Thanks for this, he has a similar setup to us. However there are two crucial differences: his rudder stock is much shorter, and his bronze casting is loose! You notice at around 07:00 how the casting drops away from the skeg? That's how he was able to fit the rudder in the first place, by it not being there. Only after the rudder is in position is the casting then slid up onto the skeg. I have to do the reverse: take the casting off first in order for the rudder to drop. Or, rather, the rudder and the casting both drop at the same time.

 

[Poecheng]

It can only have been assembled one way and, as you already understand, reversing that process is now impossible.

Seems to me you have to either destroy the skeg (easy and easy to rebuild in the manner you suggested with a bronze plate through-bolted) or destroy the casting bit by bit (difficult to do and then difficult to fabricate).
You have clearly tried and thought about it every which way. Time to get the saw out and chop the glass skeg off and you will hopefully have the rudder off very shortly afterwards. You end up with a casting you can clean up inside and bush the bearing. You already have a workable solution to the cut off skeg.

One question that comes to mind: apart from the bolts in the new plate/upper skeg and the bolts in the new lower skeg/casting, how are you going to stick it all together so this can be disassembled next time. The next time won't just be cutting through glass but also through the new bronze plate. By what method, other than bolts, is the casting to be attached and secured to the repaired skeg? Seems like you have to leave it simply bolted through but perhaps secured by encapsulating it in glass for later peeling off? or straps ?