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Worn rudder gudgeons.

Badgered Cat

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Good day everyone,

I am just wondering if anyone has tried drilling the holes in he rudder gudgeons. My rudder gudgeons are worn and are now about 2mm larger than the 6.5mm that they should be, and the holes are elongated. Tried removing them, and the bolts are well and truly corroded into the alloy backing plate.    I am not really wanting to cut hatches into my deck to fix this.

I am able to get nylon bushes that suit 6mm bolts or pintles. The bushes are 9mm in diameter, so I need to drill the gudgeons out to 9mm. The bottom gudgeons should not be huge problem, as the drill will easily fit through both. But then to drill the top gudgeon would need me to use long drill bits, which I can get. And then drill through the bottom ones and continue the drill on up and onto the top one. But in doing this, and being stainless steel, I can see the possibility, that the bottom ones will probably become enlarged slightly and even out of round, because of the drill running through I, whilst trying to drill the top ones.      

The only 3 possible ways that I can see around as to be able to drill the top gudgeon, and without damaging the bottom one in the process are as per thee following 3 options:



To try and get a right angled drive drill or drill attachment, or a flexible drill drive, that will allow to fit between the  gudgeons. The length of the right angled part, the chuck and drill would need to be less than 95cm. I have searched the internet and can no find one that is of this small size.



To try and get a drill bit that has a drilling bit length of about 3cm, but then a plain long shank of 120cm or more. Tried searching for something like this on the internet, with no luck.



To try and remove the rubber moulding from the join at the transom only, and then drill down from the top through the hull deck join, and into the top gudgeon. This could be a possibility, but frightened that the rubber moulding might not seat back into place, as it is very old now, and not that pliable.


Or the other thing, that I am thinking of, is to get the boat all tightened up elsewhere including taking slop out of rudder blade pivot point, and shimming sides of the rudder blades to stop sideways slop. And then just forget about the slop in the gudgeons. As I probably will never be sailing the boat in over 15 o 18 knot winds. And I am only racing at club level, with a couple of regattas per year, which will include the Tasmanian Catamaran Championships.


So does anyone have any ideas, helpful ones please.

Thanks David.


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That is a great bit of advice "madboutcats". Thanks very much.

I have just been given a piece of advice over the phone, by a friend of mine. He suggested to make some stainless steel plates with he correct size hole for the pintle bolts drilled into them, and to metal epoxy glue them into place at the top and bottom of each gudgeon.

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It costs about $20 to buy two hatch covers for the rear deck.  Add a bit of sickaflex and you're off.

I had the same issue, the pintles had worn and the alloy in the rudder stocks had worn too.  Lots of nasty play.

Also some of the screws broke off when I tried to remove them.

1. I bought a ceramic hole drill.  I think it was 10mm, round hole with diamond bits.  It went around the 'lost' screw and all the way through the transom.

2. I acquired new(ish) pintle brackets.  I bolted them through the transome and used the old pintles inside the transom.  I used lost of sickaflex.

3. I got rid of the stainless bushes and bought a length of DELRIN rod.  It's 10mm so the rudder stock brackets have to be drilled out so it fits.  Once I'd pushed the delrin into place I then drilled a small pilot hole as close to the centre as I could.  I then used a larger drill eventually getting the right size for the pin.


Prior to doing this though I had just drilled out the gudgeons and used a bolt.  That worked quite well too!

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Hi knobblyoldjimbo

Thanks for your advice, much appreciated. I actually did read a post somewhere on here, where you explained how you did yours.

I am very lucky, as I have no slop or movement in the stainless steel bushes in the rudder cases. So I don't need to touch them.

As to me not wanting to go down the road of putting rear deck hatches in my decks, I because I do not want anyone to think, that my boat has been a huge accident. As my port hull around the rear beam has had a touch up on the gelcoat from a scrape in the past, and the colour match was not good, I was darker than the original gel coat. Plus he job was not good, as parts were flaking away.  So I have now just repainted this section with International Toplac, and bugger me dead, the colour is now the other way, it is now lighter and brighter yellow. But it is now not flaking away.  So by me putting deck hatches would make people think, that I have had a major repair done, around where my rear beam mounts onto the port hole, and this is not the case at all.    I suppose I am mainly thinking, if I ever were to have a major accident, there, I wold not want to get into a discussion with my insurance company, with them trying to say that the boat has had major repairs. Pure cosmetics I can deal with.......but you know the way people think, and especially insurance companies. 

Anyhow, I have now purchased, or ordered the bushes to bush the gudgeons.  I am going to drill out the bottom gudgeons, and bush them. I will then try filing out the top  gudgeons with a stumpy chainsaw  file. It only needs about 1mm to be filed out to accept the bushes. If worst comes to worst, just having he bottom gudgeons bushed, will take a lot of the slop out, once each gudgeon is bolted.

I will let everyone know on here, as to how I get on with this fix.

Cheers and many thanks.


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Finally, virtually finished, removing all the slop and play in my rudders.

I was able to remove the top gudgeons from the boat, but unable to remove the bottom ones.  I drilled the pin holes in all of the gudgeons out to 9.0mm, and then I squeezed 9.5mm outside diameter, flanged  nylon bushes into the gudgeons. After inserting them I trimmed them down to be flush with the insides of the gudgeon. I then drilled a 1/4" drill through each bush. I purchased 1/4" bolts  with nyloc nuts and 2 washers per bolt, to bolt each gudgeon to the rudder.

I removed the plywood packing plate that was silicone into place behind each of the top gudgeons. I managed to purchase, a 12mm nylon kitchen chefs cutting board. I made the new packing pieces from this 12mm nylon, cut and trimmed down to size, and pre-drilled 1/4" for the mounting holes for the bolts (metal threads) from gudgeons.

Before reassembly  of the rudders to the boat, I removed the rudder blades. I drilled the pivot holes, out to 10mm in each blade. I then cut a length of polypropylene 10mm black air hose, and then jammed this into the pivot holes. I drilled the rudder stocks pivot holes out to 9.0mm and placed a flanged bush, the same as what I used on the gudgeons. Placed one each side of the rudder stock into the pivot holes, and then trimmed them flush on the inside. And ran a 1/4 drill hrough each bush.  I then reassembled the rudders, putting new bolts and nylocs in each blade, along with 2 washers per rudder.

Now I attached rudders back to the boat. To do this, to be able to get he bolts into place I did this method. I bolted the top gudgeons onto the rudder stocks, with bolts coming up from the bottom and nylocs on top. A washer at each end. After doing this to both rudders, I then attached the rudder stocks to the bottom gudgeon on each side of the boat, in same manner with new bolts, nylocs and  washers per gudgeon, leaving the top gudgeon unfixed to boat at this stage.

Now I prepared one of the nylon packing pieces that I made from a cutting board, with a good coating of silicone on the back. Pulling the top of the rudder away from the transom, I was able to place the packing piece in behind the gudgeon. Now with new 1/4" metal threads, I screwed through the gudgeon and packing plate, and in through the holes in the transom, picking up the threaded alloy plate glassed into inside of transom. I also coated the bolts with yellow gunk, that stops corrosion, before screwing them back in.  I then did this same procedure for the other side.

With the rudders now bolted back onto the boat, the last thing to do, was to tighten the new (4) bolts that are now my gudgeon pins.

I now have very tight rudders, with no play what so ever, anywhere. They are very light on the steering, as I no longer have metal against metal, but have nylon bearing surfaces. This gives a light and smooth steering.

The only thing that I am going to do, is place a 100mm circular 1mm thick Teflon disc to the side of my rudders at the pivot point. This will aid in the rudders raising and lowering more easily, and smoothly. There is no sideways movement with the rudders in the stocks, since I have bushed both the rudder blades, and stocks, pivot holes.

I hope this info has been of use to someone.

And by the way, with the 12mm packing pieces in behind the top gudgeons, my Hydrafoil rudder blades, are sitting about 50mm forward under the boat.

Cheers David.  


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Hello Pointed Reply,

Thanks for that. The photos on he facebook page posted back in October show the rudder stocks being bushed. My stainless bushes in the rudder stocks were still okay, with no wear at all. It was the gudgeons on he back of the transom that I had o plac bushes into.

I would like to note that the black bushes on the facebook page are of the type that I used for the gudgeons, 9.5mm outside diam, and 6.00mm inside diam. Mine were in white and not black.

Thanks again for your comment, much appreciated.

Cheers David.

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Putting in rear hatches has a number of advantages.

Firstly you can access and repair the rudder mounts.

Second the bungs tend to be a source of hull leaks.

You can buy curved hatches which fit pretty nicely - slightly more expensive but neater and tidier than flat ones and lots of filler.

When you put in the rear hatches, take out the bungs and fill in the holes ......

You can see where the hatches are on the Maricat FB video

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