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28 minutes ago, Sabre said:

What did the rudder come off? 

And did you find an old rudder tube hiding in the back of your boat?

 

Na not to sure whats it off. I am going to it tomorrow. I have not looked yet Sabre. Boat due out of the water on the 8th May. but I am going on her on ANZAC weekend to fit new throttle and gearshift lever set up. so will see if anything is there. (It may have been classed over) but i should be able to see something I reckon

Cheers Sabre

Steve

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from memory shaft would be close to 50mm,might be able to swap out shaft?First thing is you need to know is there existing shaft in your hull,has it just been filled.

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9 minutes ago, harrytom said:

from memory shaft would be close to 50mm,might be able to swap out shaft?First thing is you need to know is there existing shaft in your hull,has it just been filled.

So still worth picking up tomorrow Harry ?? What ya thoughts ??

Really appreciate your help on this

Steve 

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8 minutes ago, O_Smiladon said:

So still worth picking up tomorrow Harry ?? What ya thoughts ??

Really appreciate your help on this

Steve 

Can you show photo to boat builder and see if it can be changed??  how much do they want for it or does previous owner anything about the original rudder?

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15 hours ago, harrytom said:

Can you show photo to boat builder and see if it can be changed??  how much do they want for it or does previous owner anything about the original rudder?

I will show a boat builder today and get his thoughts, They want $280.00 for it.. And na but I have heard a story that Soulmate was owned by a syndicate and was at Herald Island for a while. I might touch base with the boat club there and see if anyone can fill in the gaps.

Cheers my friend

Steve

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Steve, In my view, getting a second hand rudder is unlikely to be of much benefit, and may just complicate things. I'd take a punt you'd waste the initial $280.

If you have an existing rudder tube, it is far cheaper to get the correct shaft and bearings, and build a rudder on it. Additionally, you need the right size and shape of rudder to give your boat the balance it needs. Replacing a transom hung rudder with a bodgy second hand one isn't likely to improve the handling at all.

There has to be a reason this was made into a transom hung rudder. If there are issues with it, it is going to be a lot easier to redo a transom hung rudder than renovate the back end of the boat and do a skeg rudder. You can do a transom hung rudder with a nice foil shape for handling, and a nice new tiller for asthetics. The handling comes from the foil shape, depth and size of the rudder (partly where it is positioned also, but that can be accounted for).

To remove the little keel bit and fit a suitable rudder, with bearings, top fitting and new tiller, you are somewhere in the order of $2k to $4k, even if you do a lot of it yourself. Just the engineering side of it, tube, bearings, head fitting, they will add up. You need time on hardstand, modifing the hull brings about paint and sealant systems, then new antifoul.

You would almost certainly get a substantial improvement in handling and speed with some new sails. Far more impact than the rudder. I'd go down that path first. If you want some asthetics, you could do some work on the tiller, sand and varnish, or tidy the paint etc.

On the sails, there is a wide range of places to get them from, and a wider range in pricing. Just a modest dacron set may be cheaper than you realise, and the performance will be night and day.

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36 minutes ago, Fish said:

Steve, In my view, getting a second hand rudder is unlikely to be of much benefit, and may just complicate things. I'd take a punt you'd waste the initial $280.

If you have an existing rudder tube, it is far cheaper to get the correct shaft and bearings, and build a rudder on it. Additionally, you need the right size and shape of rudder to give your boat the balance it needs. Replacing a transom hung rudder with a bodgy second hand one isn't likely to improve the handling at all.

There has to be a reason this was made into a transom hung rudder. If there are issues with it, it is going to be a lot easier to redo a transom hung rudder than renovate the back end of the boat and do a skeg rudder. You can do a transom hung rudder with a nice foil shape for handling, and a nice new tiller for asthetics. The handling comes from the foil shape, depth and size of the rudder (partly where it is positioned also, but that can be accounted for).

To remove the little keel bit and fit a suitable rudder, with bearings, top fitting and new tiller, you are somewhere in the order of $2k to $4k, even if you do a lot of it yourself. Just the engineering side of it, tube, bearings, head fitting, they will add up. You need time on hardstand, modifing the hull brings about paint and sealant systems, then new antifoul.

You would almost certainly get a substantial improvement in handling and speed with some new sails. Far more impact than the rudder. I'd go down that path first. If you want some asthetics, you could do some work on the tiller, sand and varnish, or tidy the paint etc.

On the sails, there is a wide range of places to get them from, and a wider range in pricing. Just a modest dacron set may be cheaper than you realise, and the performance will be night and day.

Hi Fish,

Thanks mate for your input. really helpful.

I guess I am lucky enough to work in an industry where i am dealing with a lot of different trades and services.

I have a good mate who owns a CNC machine, Also the engineering firm that I use for work are always happy with a box of beer to wip something up for me as we do spend a hell of a lot of money with them.

I just got back to speaking to a boat builder and he said that it can be done and that for 280 for the old rudder that is shown in the pictures that i may be able to use it for bits just as long as the bearings are ok. I am going to see the rudder today and make the call. if its no good. I will try and make the transom hung rudder a bit better so I can at least heel over with out the rudder coming out of the water. But I will still look at taking it back to original, but over time. 

I would put the call out to Cav 26 owners to give me a call when they have there boat on the hard so then i can start to make a template of there rudder.

Good things come to those who wait.

Anyhow Thanks Fish

Steve

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Just as long as you know what you are getting yourself in for ;-) Its not just a case of getting a second hand rudder, slapping in on and going sailing.

Be interesting to hear what is going on with the current rudder? How far are you healing over when it pops out? rails under, side deck under, just gently leaning over?

Is it popping out, as in the end sitting clear of the water, or "letting go" (no laminar flow, so stalls) - meaning no response when you turn the tiller. I'd expect the boat to round up and behave like a bitch under both scenarios...

Do the underwater sections have a nice foil shape, or does it look like a scaffold plank?

Noting that baggy old sails make you heel over with no forward motion, and make general handling a nightmare. There is a chance the rudder is a symptom and not the cause.

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1 hour ago, Fish said:

Just as long as you know what you are getting yourself in for ;-) Its not just a case of getting a second hand rudder, slapping in on and going sailing.

Be interesting to hear what is going on with the current rudder? How far are you healing over when it pops out? rails under, side deck under, just gently leaning over?

Is it popping out, as in the end sitting clear of the water, or "letting go" (no laminar flow, so stalls) - meaning no response when you turn the tiller. I'd expect the boat to round up and behave like a bitch under both scenarios...

Do the underwater sections have a nice foil shape, or does it look like a scaffold plank?

Noting that baggy old sails make you heel over with no forward motion, and make general handling a nightmare. There is a chance the rudder is a symptom and not the cause.

Thanks Fish.

Yeah I could be flogging a dead horse. But I may also kick myself for not trying with what i can find. I just rung the Herald Island boat club and spoke to an old guy there. He new of the Name of the boat but could not recall it to well. so no joy there. Will keep searching I guess knowledge is power right ? haha 

Cheers mate

Steve

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Hi Guys,

Well soulmate is out on the hard. YAY !!!!! 

As you can see by the picks you can see where the repair work has been done to move the skeg line up to the transom when the original rudder came off.

By The looks of things I don't think its gonna be to much of a drama to fix and get it back to the way it was.

Just need the spec's of the old rudder or someone that has a CAV out of the water that I can get some dimensions off.

The last pic is what I am thinking on doing to the transom hung rudder to make it work a bit better. 

As always guys I am open to your opinion 

P.S Pictures came out the wrong way ..Last one first , first one last lol

 

Soulmate_Rudder10.jpg

Soulmate_Rudder9.jpg

Soulmate_Rudder8.jpg

Soulmate_Rudder7.jpg

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I think that proposed modification of the transom hung rudder would have the balance of a pig. Most of the foil area is infront of the pintels. Centre of effort is too far infront of the centre of balance. I think it would bite and flick hard over all the time.

You could possibly change the rake of the pintels, to bring the rudder more vertical, but if you are going to go to that much work, may as well do all of the work and return it to original.

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Without wanting cause any offence from where I'm sitting, money spent getting her back to original could be viewed as an investment as it'd add to the current value. 

Money spent on improving the rather unique solution that's there - perhaps not so much.

 

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Rudder balance comes from the line of the pintles relative to the blade centre of effort, the rake does not matter. Hard to get your head around but the water doesn't know its raked and that's what matters, don't do what your proposing no matter what you decide.

It could probably do with a bit of a lead on it to get some balance and a better foil shape. 

What's actually wrong with how it works at the moment? 

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Hi Guys,

Well suggested mod is out !! thanks guys.

@BOIGuy I have not had a sail in her as yet. As I have been busty with life and having to fix some things on her before i could even move off the swing mooring that she was attached to

Now that she is on the hard doing her up for summer and having a sail. But when i was motoring over to the haul out. I did note the the tiller had a big vibration. This might have been prop wash going past the rudder ??? but looking at the rudder the prop is not up and close like some rudders that are very close to the prop. So the vibration/Shudder may be what i have to deal with this rudder how it stands at the moment. was doing around 3-4 knots under motor.

Any other thoughts guys. or shapes i should be looking at. ?? I have a good 3-4 months on the hard to work something out.

Cheers guys

Steve

 

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It would not be that hard to build a really good rudder. Google 'naca foils for rudders' and you will get no end of info, blogs etc.

I would recommend getting some proper advice on the design though. Either from a boat designer, or a knowledgeable amature. Naca foil shapes give the correct eliptical curve etc. But you need to understand the total surface area, the size, and the proportion of rudder infront to behind the rudder shaft. You also need to match all of that to the size, type and characteristics of your boat. Either that or go and copy another Cav 26 rudder.

You'll need a proper shaft made up, with tines (spikey bits running fore and aft inside the rudder blade). Some proper bearings and a rudder tube. It would be fairly easy to cut in a new rudder tube on the hard. Henley's do a fancy plastic tube and matching bearings at a good price. I used them to refurb my old copper rudder tube. They would be able to supply and machine up a shaft also.

The building bit, you can either use PVC foam, or wood, or wood laiminates. Get the shape about right, attached to the shaft and tines, and fibreglass it all up, smooth, fair and paint. Key attributes are knowing how to work expoxy resin, patients, and an ability to know what you don't know. Oh, and time.

If you really want, you could do one in carbon fibre skin. If you did a PVC foam with carbon skin, the weight you would save at the end of the boat would help performance and reduce hobby horsing. If you really wanted to get carried away, you could do a carbon shaft, but that MAY be getting a little over spec'ed...

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I've made and reshaped several rudders and always tried to get close to the basic NACA 0012 profile. Search online, you can get find calculators that will print out profiles etc. 

For what you have it's a lot cheaper to stick with transom hung and there is nothing wrong with that. 

If the pintles etc look strongenough. I would try add a couple of inches on the front of what you have and get a bit of foil shape in it. That will take some load off the tiller, improve performance and won't cost much. 

You really need to sail it a bit after that to decide if you want to put big money into it for either a new transom hung or spade rudder. 

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Agree with BOI Guy, you could dramatically improve things with the existing rudder by doing a NACA foil shape and a little bit of area infront of the pintel line. The area infront of the pintel line gives it more balance, so the tiller is much lighter.

With something like the NACA 0012 profile, you get much better flow over the blade, so it 'holds on' much better and doesn't stall / let go when it is loaded up. It currently looks like a plank with square ends and parallel sides, is that right?

It is possible that it is the lack of foil shape that makes it 'let go', and it feels to you like it has come out of the water when the boat is heeled over. A stalled rudder would feel the same.

There are many many boats with transom hung rudders that work very well. I don't think the issue is that this one is transom hung, it is the design / details of the rudder itself. The advantage with doing a transom hung one, is you don't have to do it all on the hard. That, and it would be a fair bit quicker and cheaper.

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1 hour ago, Fish said:

The advantage with doing a transom hung one, is you don't have to do it all on the hard. That, and it would be a fair bit quicker and cheaper.

...and increases space in the cockpit

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