Ruddershaft cracked...

[ProjectManaia]

Hello everyone,
We just experienced a not so soft touching of coral recently bending and cracking the rudder on the shaft.
It is all aluminium 4inch shaft and hollow alu rudder welded onto it. After the grounding it is cracked on the top where the shaft is going into the rudder.
Unfortunately we are out in remote islands and closes alu welding place is a good week sail away.
I can drop out the rudder and attempt an patchworkjob but am somewhat wondering with the shaft leading inside it should be strong enough still? It is only cracked in the front of the joint and the back appears good and strong so unless we run her aground again on the exact same spot? But is it worth the risk? And really what are the options?
Drilling holes throuh rudder and shaft and put bolts theough until finding a welder?
And how bad is the steering with only one rudder or at all possible under sail?
Thanks for input already!

[UpOnStands]

Is the shaft itself bent?
If possible recheck, the crack is in the shaft or in the weld to the blade?
If you have dropped the rudder already proceed slowly on one in good weather window.

[ProjectManaia]

The shaft itself seems fine, no bent or crack.
The crack is on the forward side of the weld between shaft and blade.
Riht now we are tied up on a mooring with little time to make things work or attempt to anyways, thats why i am looking for some advice.
Thanks for the reply!

[UpOnStands]

My thinking. If the crack is through the center face of the weld you've got a worry.
Either the welding material itself is defective or the rudder is badly skewed on the shaft (overloaded the weld).
If the "crack" is at the root of the weld and does not enter the shaft its possible that the welding conditions were not optimum and a full penetration weld was not actually formed. I've seen this in industrial welds in aluminum. Fairly easy to dye penetrant test the rest of the welds (P&S), grind out the poor weld and redo it. Not so difficult if the welder is experienced.
This is the type of test you want -- This product is unknown to me so its not a recommendation as to brand. Most shipyards will have equivalent.
CANTESCO K801S Dye Penetrant Kit, Solvent Removable, 8 Can Kit

[ProjectManaia]

Thanks for the replies, i had another good look around, it is cracked in the back and more than half way forward on stbd but less on pt.
So i am thinking drop the rudder, drill holes, bolt the blade to the shaft and go easy until it is fixed.... about 5 days sail away...

[UpOnStands]

Do you have a small rotary grinding tool or even round hand file?
Carefully remove the weld next the shaft and find out if the crack runs along the shaft surface or runs into the shaft.
Given the extent of your problem, the "crack" probably runs between the weld and the shaft, i.e. along the shaft, and bolting seems reasonable.
Into the shaft is more dangerous and bolts won't help.

[ProjectManaia]

Ok, just tried to get the rudder out, but here is the issues... in order to disconnect from the tiller or upper part i need to lift it a bit to get the onnecting bolt out. With the light bend i cant do that, so dropping is not an option right now.
The crack goes about half way aroundmwith its center sloghtly to port from forward.
Maximum gap is about 1mm. But here is the thing that gives me hope: inside the crack i can see another pole, which makes me think some smart welder put a pipe over the shaft which he then connected to the rudder, taking immediate strain off the shaft.
This again means there shouldnt be too muc force on the broken bit?
Maybe im wrong but.... running low on options.
Can still attempt to hand drill a hole under water and put a bolt in... just not sure how long that might take....

[paxfish]

Just an idea - see if someone in the anchorage has a gopro you can borrow to get some photos for the experts on the forum. They can get in there pretty close....

[UpOnStands]

+1 on the camera
Suggest that you don't drill underwater. Sounds like you did not fabricate the rudder so you are not sure of internal design/parts.

If you disconnect the steering linkage can you rotate the rudder 90 degrees port or stbd and raise the rudder a bit more?

[ProjectManaia]

I could turn 90 degrees, no more though.
And unfortunetly not possible to raise it more (assume a bend isnthe issue there...)

[ProjectManaia]

Originally Posted by paxfish

Just an idea - see if someone in the anchorage has a gopro you can borrow to get some photos for the experts on the forum. They can get in there pretty close....

Here pictures of the victim.
Close up of either side, you can see one side is worse than the other, but the shadt is inside and not cracked.
On the further away picture you can tell that it is bend backwards...
On one of the last refit videos on our youtube channel (sea nomad exposed, unsure which exact episode though) you can see the rudder without paint and there is vertical welds in the middle of the blade which makes me think the shaft is secured to the blad inside as well...
Www.youtube.com/c/projectmanaia
So if thats the case things should be fine...?

[UpOnStands]

Thanks for the photos. Can't say its looking like something quick to fix.
The narrator says "stainless steel rudder" but your first post says aluminum?
Episode 8 New Keels

https://www.youtube.com/watch?v=gnxFF8S8xSk

Episode 7 @ 1:06 mark

https://www.youtube.com/watch?v=imSURr2oMiY

shows stbd side as boat is lifted out. There is no rudder blade just rudder
stock. Who took the blade off? How?

[ProjectManaia]

Originally Posted by UpOnStands

Thanks for the photos. Can't say its looking like something quick to fix.
Episode 8 New Keels

The narrator says "stainless steel rudder" but your first post says aluminum?
Episode 7 @ 1:06 mark

shows stbd side as boat is lifted out. There is no rudder blade just rudder
stock. Who took the blade off? How?

Thank you for the reply!
That was ranong shipyard where they didnt do aluminium so we had it made in stainless.
The old one had dropped off, the boat was in a horrible state when i got it.
This one was remade in phuket about half a year ago now (diffetent video) but should be two episodes before "sailing sea nomad - expedition sailboat afloat"
Sorry i cant give better video answers, connection is really bad here in myanmar islands....
But it now is aluminium... but it clearly shows that the shaft sticks into the blade itself, thats why i am thinking bolts or pop ribbets maybe?

[UpOnStands]

Originally Posted by ProjectManaia

Attachment 144769

pls confirm. Is that marine growth actually in the crack?

[UpOnStands]

Seems as if the rudder is secured to the rudder stock by a nut or bolt to the lower end of the stock. Can you show us a photo in the steering compartment. Particularly what part is the quadrant attached to/driving?