Guest Posted August 1, 2011 Share Posted August 1, 2011 my variant 22 bilge keel got stuck on a reef in a falling tide..ouch sack the navigator see attachedpick - the stock(bronze) snapped where there is a bolt /spine in the blade any tips on how to repair appreciated...or is this a boatbuilder job.i'm trying to avoid over captiltalising a 2k trademe yacht Link to post Share on other sites
Marshy 30 Posted August 1, 2011 Share Posted August 1, 2011 Hmm I hate to be the bearer of bad news but i cant imagine you will be able to simply "Repair" the rudder stock. Think about the torsion and loads that go on that little piece of metal when sailing in any kind of sea or breeze. So its not a simple butt it back together and repair it job. Most Bronze cant easily be welded strongly enough from my understanding (Although i could be wrong) So you may have to replace the whole stock through the whole rudder (Or at least thats what i would be looking at doing given the loads going through a rudder. Whether you can get the whole stock off the blade without damaging the rudder will decide how much of a major that it. If you can remove it yourself you may be able to get a new stock fabricated somewhere out of Stainless, or be incredibly lucky and find someone game enough to repair the existing rudder stock. Think of the stock as like a drive shaft, you wouldnt re-weld a broken drive shaft really so you probably wouldnt weld or repair a snapped rudder stock. This is where i love my Carbon fiber rudder that when it snaps i just grind and carbon it back up! Link to post Share on other sites
Guest Posted August 1, 2011 Share Posted August 1, 2011 Also try Machine Part Welders , they are specialists in welding. They may be able to drill out the stock and put a sacrificial shart in to strengthen the bronze then weld. These guys are always happy to help. Link to post Share on other sites
Guest Posted August 1, 2011 Share Posted August 1, 2011 ok thanks for tips ...sounds like a job for the welders who understand these load bearing stuff .. chrs Link to post Share on other sites
Marshy 30 Posted August 1, 2011 Share Posted August 1, 2011 Could always try this as an option too: http://www.trademe.co.nz/motors/boats-m ... 911309.htm He looks to be selling the parts seperately. While his rudder itself may be a different shape, if the stock is in working order and the same diameter etc you may be able to re-shape his rudder the same as yours, and use that instead. Might be cheaper? Link to post Share on other sites
Guest Posted August 1, 2011 Share Posted August 1, 2011 Marshy - thanks for the pointer to trade me variant auction - have asked the seller about selling a spare rudder but he wants to wait and see if another project person buys all the kit Link to post Share on other sites
Guest Posted March 9, 2012 Share Posted March 9, 2012 By the magic of trade me I now have a new stainless rudder stock for $10. Shame that its 2mm too large .. off to the machinist for a bit of re work Link to post Share on other sites
w44vi 17 Posted March 9, 2012 Share Posted March 9, 2012 Well done the machine shop will be able to use your old stock as a template and you'll be sailing again in no time Link to post Share on other sites
wheels 543 Posted March 9, 2012 Share Posted March 9, 2012 I would weld a "shoe"(plate) to the shaft that then bolts to the Rudder. Link to post Share on other sites
Guest Posted March 9, 2012 Share Posted March 9, 2012 I would try an avoid any welding to the stock within 150/200mm of the bottom of the boat. Link to post Share on other sites
wheels 543 Posted March 10, 2012 Share Posted March 10, 2012 Can you explain why FNG. I am obviously missing something and curious. Link to post Share on other sites
tennisraindelay 1 Posted March 10, 2012 Share Posted March 10, 2012 Also try Machine Part Welders , they are specialists in welding. They may be able to drill out the stock and put a sacrificial shart in to strengthen the bronze then weld. These guys are always happy to help. i know this this is an old post but it cracked me up. 'sacrificial shart' hahahaha! Link to post Share on other sites
Guest Posted March 10, 2012 Share Posted March 10, 2012 Can you explain why FNG. I am obviously missing something and curious. welding metal changes it's properties, I believe that it's weakend 10% even when welded properly. ( happy to be corrected ) due to heat stresses etc. Now in the case of this little boat thats had a failure already, why would you go and possibly weaken the replacement shaft where the most strength is needed, when you should be trying to make it stronger Link to post Share on other sites
wheels 543 Posted March 10, 2012 Share Posted March 10, 2012 Arrr righty, get ya. Hope this helps. OK firstly, SST does not change it's properties due to heat. Unlike plain steel, You can not harden of Soften SST with heat treatment. The strength of SST's are given by the percentages of additives in the metal. Like how much chromium, nickel and so on. You do however, just very slightly change the physical property of SST when you melt it via welding. It's only fractionaly, but enough to cause a "disimilar metal" problem right at that joint. If the SST is not protected by an anode, the weld will likely be the first place to start eating away. TIG welding is one of the strongest means of welding SST. Mainly because it is easy to get a high purity weld right the way through the entire area of Parent material. Mig welding can create the next best weld, but you need a skilled hand and eye and a damn good machine to lay a perfect structural weld. In both cases above, it is critical to use the correct Gas and Wire type to get the best weld. Arc welding can lay down a stunning looking weld, but I find that is as far as it goes. You can never be totaly sure if the weld is really clean all the way through without Xraying or Ultrasound checking the weld afterwards. What I would do in this particular case. OK, so without getting my hands on the rudder and looking at how it was actually made, I can only give a couple of thoughts. From some comments made now, I take it the shaft goes right through the length of the rudder. If the shaft can be removed, I would look at putting a new shaft right through. Should be easy enough to do as I expect it is welded top and bottom. I am also slightly concerned that the shaft does not look very large in daiameter for the rudder size. So I would be worried about the stress the shaft has endured over it's life, in other parts along it's length. A new shaft would be best idea. Second idea would be if shaft can not be removed from rudder. Replace shaft to top of rudder and weld to that part a "shoe". Although not the correct term, I can not think of a better term, apart from "plate" or "flange". This then either bolts to the top of the rudder, or welds to the top of the rudder. The rudder on my boat has this vary means of connection and it bolts to my rudder. So I can unbolt the rudder and remove it without removing the stock. Why use a "shoe"? well it would be difficult to get a perfect alignment of the shaft to rudder, plus any weld would be only as large as the Shaft daiameter. A shoe can have a hole for the saft to slip into and then welded top and bottom giving greater strength without weakening the joint by relying solely on a weld. Plus the top weld can be a fillit that gives a greater surface area of mating around the shaft. If done well, there should be no reason why a new shaft added to the rudder can not be as strong as a new shaft all the way through. Not so sure if i would want to reuse the old shaft again though. Link to post Share on other sites
Guest Posted March 31, 2012 Share Posted March 31, 2012 Thanks for the design ideas - the bronze stock (25mm)goes to bottom of rudder blade (500 w x 700 l ) from what i can tell and is not atached to the bottom plate / shoe on the rudder - the bottom plate pin has worn off and no longer sits in the rudder bearing at the bottom of the skeg and the rudder bear hole has worn out to 25mm so all that has to be replaced as well... Took the trademe stainless shaft to the machinists who said stainless was too hard /too costly in time to rework and to go to stainless products and get 1 m stainless 316 25mm and start again. All look too technical for an old variant ... may just move the centre transom mounted outboard to port and put a transom gudgeon/pidgeon mount rudder on Link to post Share on other sites
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