Rudder Problems

[Malcolm Sadler]

Thanks Justin and Dennis

Those will be very helpful.

Cheers

Malcolm

[Malcolm Sadler]

One of our members, Lee Fuller (Kira), has a friend who is a stainless steel fabricator, and at least three boat owners are going to commission cheek plates to strengthen the top of the rudder, in order to mend, or avoid, the splitting which has been experienced so often.

We intend looking closely at the designs used by Ladybird and Kaliope, referred to above in this thread. Either or both may be perfect - or may be capable of refinement. Let's pool our thoughts. Coming up with the best design is the first objective of this post.

Secondly, there may be economies of scale in going to the same S/S fabricator. For any members who think that is a good idea, I suggest that we identify a design that will work on as many rudders as possible, and then invite members who want to make this modification to post on this thread so we can assess the demand and aggregate all orders We will then ask for a unit price and people can decide if they want to go to this fabricator.

I gather from comments on the Ladybird and Kaliope photos of their designs that some rudders need the cheeks to have a notch to accommodate the 'female' pintle fittings (there must be a technical name for those). There may be more subtle differences too - eg shape of the rudder, its profile (how curved), positioning of the hole for the tiller pivot bolt, etc. It would be helpful if we could identify the various different rudder designs. I can imagine at least two, namely SA built boats and Honnor Marine boats, but there may be two or more versions of each.

How to do this? - perhaps post photos of the top of your rudder with a tape measure showing critical measurements.

Or make a carboard template of the outline of each component and the exact centes of holes to be drilled, and post it to someone who can compare all of them. I am not an engineer, but I don't mind doing this if no-one else has time or inclination.

Of course, we may find there are too many differences to make a single design possible. In that case each owner may need to send his/her own template to their chosen fabricator, and there may be no mileage in this centralised approach.

But let's see where this goes - so all comments welcome.

Cheers

Malcolm

PS - The Forum rightly has a policy of not promoting any particular business or supplier. Hence my two proposals in this post - pooling ideas to get the best design, and separarately from that, seeing whether we can all get a good value deal by going to the same supplier. It would be nice if Honnor Marine, as builder of the Cape Cutter, could provide what we need as a retrofit improvement, but from my correspondence with them it seems they have a new method of manufacturing a more robust rudder (good news!) and they can't really repair old rudders.

[Justin Greig]

"'female' pintle fittings"
otherwise known as gudgeons!

[Andrew Scullion]

Hello Malcolm,

As I am the current owner of Ladybird, and an Engineer (with CAD software), I thought I could pitch in and help.

I am pleased to confirm that the modification to Ladybird has proved itself over some serious sailing since it was installed by the previous owner Ian Barnes. This is over ten years of testing including some heavy weather sailing.

As an engineer, I am guessing here from memory, but I would not worry too much about the slight differences between the rudders from what I have seen between them. We need to check but I think a general design that works for all rudders is possible because the upgrade does not need the plates to go right to the edge of the rudder to be effective from a strength-improving engineering point of view. The modification is spreading the load of the torque further down the GRP and we can probably achieve this goal for all rudders without the plate going right up to the edges of some parts of some rudders.

The idea of everyone checking their rudder against the design template is good and you can easily print an actual 1:1 size paper template from a CAD file. I think I can probably post a .pdf that everyone can print which should come out of anyone's printer 1:1 the correct size assuming that printer settings are not scaling it when printed. This could be a method for everyone to remotely confirm a standard design.

I am happy to add further details of Ladybird's modification if needed.

As a bonus, on a separate topic, if you match the thickness of Ladybird's upgrade, I have designed a wind self-steering setup which attaches to this rudder upgrade and I am happy to share that design with those who are interested.

Cheers,
Andrew

[Chris Wicks]

https://www.facebook.com/media/set/?set ... f269fdc4ad

Here are a few pictures of Kaliope's repair. We discovered the leading edge of the rudder from the top to just above the water line had failed where the two halves of the rudder were joined. It turned out there was a lot of gelcoat along this seam and hardly any GRP mat. When we reinforced the tiller / rudder connection last summer we then transferred the load further down to this seam causing failure. It has now been reinforced with Kevlar reinforced mat. A nice job. As I didn't have enough Oxford blue gel coat I have a small area of GRp that is a bit lighter than it should be, but I hope now a rudder that is strong and sealed against water ingress...

[zimp]

...

As a bonus, on a separate topic, if you match the thickness of Ladybird's upgrade, I have designed a wind self-steering setup which attaches to this rudder upgrade and I am happy to share that design with those who are interested.

Cheers,
Andrew

Hello Andriew,
I've been playing with self=steering, with little succes. Looking forward to your design!
Bert

[Chris Wicks]

Sorry but I can't upload the photos of Kaliopes repair. I've sent them to Malcolm. Please share them and use them as required. It proved to be a brilliant solution after 10 years of hard use. In the Kaliope version a small alteration to the plate was made to fit around the upper pintle.

When Dipper (83) and Eliza Nell (110) arrived in Greece they both had similar problems. Reinforcing plates were then arranged by our local boatyard. They were slightly shorter to fit above the pintles. Rather than make stainless steel spacers for the tiller he made them out of wood.

Best wishes

Chris

[Malcolm Sadler]

Andrew suggests

The idea of everyone checking their rudder against the design template is good and you can easily print an actual 1:1 size paper template from a CAD file. I think I can probably post a .pdf that everyone can print which should come out of anyone's printer 1:1 the correct size assuming that printer settings are not scaling it when printed. This could be a method for everyone to remotely confirm a standard design.

Yes please Andrew - can you do that? Can it be made accessible on this Forum and also on the WhatsApp thread (I started a new one as some people have difficulty using the Forum - I will invite you and Chris and anyone who wants I into WhatsApp chat)

Will the PDF show precisely the centres of all the holes?

And can you write on it the diameters/gauge of the holes drilled and the bolt sizes please?

You will see that Lee Fuller has lined up his contact to make them if anyone chooses that.

I would also like to get a template for the spacers that will have to fit inside the tiller brackets. I rather favour making the spacers out of wood rather than S/S as Chris mentioned - it will save a bit of weight

Cheers

Malcolm

[Andrew Scullion]

Yes please Andrew - can you do that? Can it be made accessible on this Forum and also on the WhatsApp thread (I started a new one as some people have difficulty using the Forum - I will invite you and Chris and anyone who wants I into WhatsApp chat)

Will the PDF show precisely the centres of all the holes?

And can you write on it the diameters/gauge of the holes drilled and the bolt sizes please?

Cheers

Malcolm

I will sort something out and post it, bear with me as it will have to be done at the weekend.
Andrew

[Andrew Scullion]

cc19_rudder_plate.pdf

The attached is a starting point for a standard design based on the plate installed on Ladybird.

Please print the .pdf and check that the dimensioned line is 100mm long to calibrate the scale.
If this is not the case, your printer settings may be scaling the image. Check that the printer settings in your .pdf software are not scaling the print.

You can then cut out the template and check it against your rudder for fit and clashes.

Adjusting the position of the six attachment bolt holes or the shape of the plate should mean that we can produce a generic design which will work for all rudders.

If this template causes an issue with your rudder, then I need a precise markup of the problem to update the design.
The important point to note is the design is all dimensioned from the centre mark of the tiller pivot bolt hole (labelled on the drawing).
Therefore, if this template causes an issue with your rudder, you need to provide a marked-up copy of the template back to me with any new lines dimensioned from this centre mark position.
The reason for using this as the zero for dimensions is because this is the common centre point which will position the plate on all rudders.

Any questions please let me know.
When we have confirmation that the template is good or needs refining, I can update the design as required and post a new template for people to check.
Once finalised I can share the CAD files for anyone to have it manufactured.

Andrew