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Replacing rudder stock (tube?) on Hood 20

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Created by carlsnilsson 3 months ago, 22 Jun 2019
carlsnilsson
TAS, 3 posts
22 Jun 2019 7:55PM
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Back in 2017 re a corroded rudder tube on a Hood 20, Chris 249 wrote "It's not a huge job to fit a new tube". I have just managed to severely bend the rudder tube on my Hood 20 where it exits the hull, also cracking the top fibreglass (?) on the rudder itself where the tube goes in. My first thought was to get the rudder off and see if the s/s tube could be straightened (maybe 30 - 40 deg bend), but if "It's not a huge job to fit a new tube", maybe that would be the way to go. I don't quite understand how that could be so - does not the tube have a bunch of arms or plates welded to it down through the rudder? Can Chris 249 or some knowledgeable person explain to me how the rudder is constructed and how one might go about replacing the tube? Replies much appreciated. I'll post this now and add a photo tomorrow.

carlsnilsson
TAS, 3 posts
23 Jun 2019 10:58PM
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Re my post on the bent rudder post of my Hood 20. The bend in the tube is about 30 deg and penetrates into the rudder itself for a small distance. It has cracked the fibreglass/bog at the top and in the photos I have inserted a (new) scalpel blade into the crack (regardless of expense). That appears to be where the bending post has done its work. The bend is fairly uniform over 4-5 cm and the tube does not appear to be cracked or kinked or unduly distorted. I will try to repair this - first job is to drop the rudder, then carve away a bit of the rudder and cracked piece to expose the bent tube bit. That is why I hoped someone could enlighten me on how these rudders are constructed - presumably I am dealing with fibreglass and resin to expose the tube. My thought at this stage is to use heat in trying to straighten the stainless steel tube - some anealing should be useful and there are ways in which to strengthen the tube over/through that section after the straightening. many conflicting view on this subject on the web - that's where my thinking is at this early time. I will seek further advice as I progress - I'm not in any hurry. Two pics showing the extent of the bend and the bend and top of rudder in detail. Advice welcome - particularly from those with experience in straightening bent s/s tube of about 25 mm diam (probably of fairly thick wall, but I don't know yet) or knowledge of what lies beneath the fibreglass at the top of the rudder.






Ramona
NSW, 5220 posts
24 Jun 2019 8:10AM
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Slightly confused. From your first post I thought the rudder tube had bent but now it looks like the rudder shaft is bent. The shaft will be extended down into the rudder blade and will have two or three tangs welded on. The blade will probably have been moulded in two halves and stuck together, sometimes hollow, sometimes foam filled. Either way it would be full of water when the boat is in the water. This is not a very big boat and the sizes of SS tubes involved are not that expensive and easily available. I would be inclined to source a new tube and a new shaft and start from scratch. Use epoxy and the appropriate cloths to glue the tube in. Weld tangs on to the new shaft and laminate a new timber rudder blade and sheath that with epoxy and cloth. This is a good opportunity to make a decent shaped rudder! There is not much chance of getting that bent rudder shaft straight again.
Most Hood 20's will be in NSW. Where are you actually situated? Is that your trailer?

carlsnilsson
TAS, 3 posts
24 Jun 2019 10:41PM
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Thank you for your comments Ramona. You are right, I seem to have confused the terms rudder "shaft" and rudder "tube". It is indeed the shaft that is bent. I half-assumed it would be a tube, but I dropped the rudder out today and it appears to be a solid shaft. It certainly is at the top where the tiller attaches. I am somewhat surprised that it seems to have bent more easily than I might have expected. That may indicate that it had been bent before and straightened with heat, thus annealing the shaft at that point - but I am speculating. You may prefer to build a new rudder - at this point I am inclined to first try to repair the present one. I don't mind the annealing at this point and I will try some heating and straightening again. The fact that the shaft does not appear to have been distorted out of round where bent suggests to me that it is still probably solid at this juncture. I would rather the rudder shaft bend than crack or tear the boat hull. You also use both terms "shaft" and "tube" with respect to a new rudder. When you refer to "tube", do you refer to the tube above the water line and within the boat within which the shaft rotates?
I did buy this Hood 20 in NSW , but there is at least another one near Hobart where I live. It is indeed my trailer, properly purchased with the boat.
I just checked your profile Ramona and it appears we have a few things in common: I too grew up in Adelaide and learned to sail there - first crewing as a 13 yr old in Cadet dinghies, then I acquired an old heavyweight sharpie "Kismet" which I sailed with school mates with conspicuous lack of success in races with the Brighton and Seacliff Yacht Club (1951-56). I also worked for the RAN at Rushcutter's Bay 1972-82. You may recall HMAS Kimbla and HMAS Diamantina and I spent quite a lot of time on Kimbla down as far as lat 50 S getting cold and wet. I took some guide from your profile and put a few of those details in mine. Regards.

Ramona
NSW, 5220 posts
25 Jun 2019 8:21AM
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carlsnilsson said..
Thank you for your comments Ramona. You are right, I seem to have confused the terms rudder "shaft" and rudder "tube". It is indeed the shaft that is bent. I half-assumed it would be a tube, but I dropped the rudder out today and it appears to be a solid shaft. It certainly is at the top where the tiller attaches. I am somewhat surprised that it seems to have bent more easily than I might have expected. That may indicate that it had been bent before and straightened with heat, thus annealing the shaft at that point - but I am speculating. You may prefer to build a new rudder - at this point I am inclined to first try to repair the present one. I don't mind the annealing at this point and I will try some heating and straightening again. The fact that the shaft does not appear to have been distorted out of round where bent suggests to me that it is still probably solid at this juncture. I would rather the rudder shaft bend than crack or tear the boat hull. You also use both terms "shaft" and "tube" with respect to a new rudder. When you refer to "tube", do you refer to the tube above the water line and within the boat within which the shaft rotates?
I did buy this Hood 20 in NSW , but there is at least another one near Hobart where I live. It is indeed my trailer, properly purchased with the boat.
I just checked your profile Ramona and it appears we have a few things in common: I too grew up in Adelaide and learned to sail there - first crewing as a 13 yr old in Cadet dinghies, then I acquired an old heavyweight sharpie "Kismet" which I sailed with school mates with conspicuous lack of success in races with the Brighton and Seacliff Yacht Club (1951-56). I also worked for the RAN at Rushcutter's Bay 1972-82. You may recall HMAS Kimbla and HMAS Diamantina and I spent quite a lot of time on Kimbla down as far as lat 50 S getting cold and wet. I took some guide from your profile and put a few of those details in mine. Regards.


I actually grew up in Tumby Bay. I mentioned the trailer only because I presumed you were working on this project in your back yard so this is a much easier job. The tube is the part in the hull that the shaft rotates in. Probably SS and 'glassed in to the deck and hull and may or may not have bearings. My quarter tonner I owned previously at 26 feet had the same arrangement and the shaft rotated in the SS tube with no bearings. After a few years there will be some wear and I used strips of plastic milk containers as shims.
If the shaft is bent where it enters the tube it is too close to the fibreglass on the rudder for heat. It's only 25mm or so, so will bend fairly easy with a hydraulic press cold. You might have to consider splitting the blade back in to two halves and straightening the bare shaft.
I was fortunate enough not to serve on HMAS Kimbla but several of my fiends did and they enjoyed the experience. Not a ship I would want to be down South in! I used to see Diamantina doing surveys around my hometown when I was still at school!

Chris249
268 posts
25 Jun 2019 6:47AM
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carlsnilsson said..
Back in 2017 re a corroded rudder tube on a Hood 20, Chris 249 wrote "It's not a huge job to fit a new tube". I have just managed to severely bend the rudder tube on my Hood 20 where it exits the hull, also cracking the top fibreglass (?) on the rudder itself where the tube goes in. My first thought was to get the rudder off and see if the s/s tube could be straightened (maybe 30 - 40 deg bend), but if "It's not a huge job to fit a new tube", maybe that would be the way to go. I don't quite understand how that could be so - does not the tube have a bunch of arms or plates welded to it down through the rudder? Can Chris 249 or some knowledgeable person explain to me how the rudder is constructed and how one might go about replacing the tube? Replies much appreciated. I'll post this now and add a photo tomorrow.



As Ramona said, 'glassing in a new tube is not a huge job. I'd second all his other remarks.

I had a rudder shaft on my old 20 footer bent, and not even the pros could get it perfectly straight again. You could always feel a bit of extra resistance at one angle when it was put back in the boat. I've got no experience with trying to straighten a shaft myself.



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"Replacing rudder stock (tube?) on Hood 20" started by carlsnilsson