Placement of Windvane Steering System.

[Tiki2]

Hearing your concerns about the overhang and complexity of a system over the stern of the boat I wonder if you had considered Cape Horn vanes as an option for you?

[GILow]

Originally Posted by Tiki2

Hearing your concerns about the overhang and complexity of a system over the stern of the boat I wonder if you had considered Cape Horn vanes as an option for you?

HI Tiki2,

Do you know, I had not found those in my searching, thank you for the reference. At first glance they seem very compact indeed. I will find out more about them.

Though, in fairness, if they don't work as an auxiliary rudder I'll probably stick with the current plan as I have become increasingly attracted to the idea of the auxiliary rudder as a backup.

Thanks again,

Matt

[JPA Cate]

A couple of things occur to me:

One, every boat I've ever sailed tends to "squat" when sailing fast off the wind. How much does Manera squat? You'll want to plan around that.

Two, with our auxiliary rudder wind vane, we had stabiliser lines going to the cockpit, to make sure it tracked straight, or to be able to cast off one side, and pull the aux. rudder over to help back out of a slip, because as your way comes on, then you can have two rudders helping to turn your boat--a good.

This is not knowledge based at all, but I personally would feel more comfortable with the aux. rudder at the centerline, mostly because I think she will perform more the same for either tack/gybe. When you set things at night, in particular, your muscle memory plays a large part in how you do things, and I'd worry I'd "forget" how to do it right for port vs. stbd. Silly girl.

Ann

[GILow]

Originally Posted by Ann T. Cate

A couple of things occur to me:

One, every boat I've ever sailed tends to "squat" when sailing fast off the wind. How much does Manera squat? You'll want to plan around that.

Two, with our auxiliary rudder wind vane, we had stabiliser lines going to the cockpit, to make sure it tracked straight, or to be able to cast off one side, and pull the aux. rudder over to help back out of a slip, because as your way comes on, then you can have two rudders helping to turn your boat--a good.

This is not knowledge based at all, but I personally would feel more comfortable with the aux. rudder at the centerline, mostly because I think she will perform more the same for either tack/gybe. When you set things at night, in particular, your muscle memory plays a large part in how you do things, and I'd worry I'd "forget" how to do it right for port vs. stbd. Silly girl.

Ann

Hi Ann, great to have you on the case...

In order...

1. I have a problem with the sailing fast off the wind concern, as, to the best of my understanding, we haven't managed to do the "fast" bit yet. So far, at up to 7.4 knots through the water (Sally holds that record), I've not observed anything to indicate how much she'll do this if at all. Banjoship might be able to shed some light here, I will ask him.

2. Good idea about the lines, I will look into a way of doing the same. Although my intention is to have this thing out of the water when coming and going from the pen, I conceed it might actually assist us, as per your comment and those from others with auxiliary rudders.

3. The asymetric aspect has bothered many CF members for different reasons. I will pay more attention to getting the device central. I was looking at the stern yesterday from land (yeh gods, that's a broad backside!) and realised I could bring the device closer to the centerline than I had originally anticipated, but again, this will depend on the compactness of the brackets, which brings me right back around to the pillowblock bearing issue.


Matt

[GILow]

Originally Posted by Tiki2

Hearing your concerns about the overhang and complexity of a system over the stern of the boat I wonder if you had considered Cape Horn vanes as an option for you?

Ahh rats... turns out to be a servo pendulum. Neat though. But not what I am after.

Matt

[Normanby]

Hey Matt,
Really enjoying following your progress, i look forward to seeing photos when you get around to the installation.

I don't mean to drift your thread, but in your extensive research have you ever seen a trim tab self steering system on a boat that had an inboard rudder?

Having read John Lechter's book a few times, i've decided that a trim tab is the thing for me! But my Compass 28 has an inboard rudder - great big barn door of a thing at the back end of the full-ish keel. Must be some way to use a trim tab - an engineering student's PHD perhaps?

Matt

[robert sailor]

Just keep in mind that aux rudders are under much more stress than servo/p vanes so everything has to be built very strong.

[GILow]

Originally Posted by Normanby

Hey Matt,
Really enjoying following your progress, i look forward to seeing photos when you get around to the installation.

I don't mean to drift your thread, but in your extensive research have you ever seen a trim tab self steering system on a boat that had an inboard rudder?

Having read John Lechter's book a few times, i've decided that a trim tab is the thing for me! But my Compass 28 has an inboard rudder - great big barn door of a thing at the back end of the full-ish keel. Must be some way to use a trim tab - an engineering student's PHD perhaps?

Matt

Hi Matt (great name),

We have a very similar rudder setup to yours. I have not seen trim tabs on an inboard rudder anywhere yet, I suppose because it would be well near impossible to keep the thing moving freely and not blocking up with barnacles etc.

One thing that has been apparent from all of the reading I have done is that there is very little force available from the wind vane itself. CF members like Jim who have built there own often seem to run into problems with drag on the control cables etc, and some of the early systems had simply ridiculous vane sizes in an attempt to overcome this problem. So unless you could think of some way of encapsulating the whole thing in a watertight environment I would say it would be impossible.

I did doodle a design that used a set of very strong magnets rotated inside the trailing edge of the rudder to control the trim tab. I was feeling quite excited till I thought about the effect on the compass. Really glad I did not get around to building THAT particular design.

But, are you considering this because, like me, you find the idea of the big bracket sticking out the back to be a problem? If so, would the pillowblock bearings be a solution for you also? (Seductive picture to follow!)


Matt

[GILow]

Originally Posted by robert sailor

Just keep in mind that aux rudders are under much more stress than servo/p vanes so everything has to be built very strong.

Funny you should mention that... what do you think of those pillow block bearings then? Surely they would stronger than some long armed bracket do you think?

But yes, the rest of it will have to be solid, thinking 1.5" SS tube for the main shaft, with a 4mm wall thickness. 4 or 5mm plate for the flanges that support the blade. Blade itself made with a 1" SS tube core, with ss ribs, foam core and glassed outer.

This is all a bit rough at the moment, I need to get into the steel shop and get my hands of some of this stuff and "feel" the strength.

Matt

[El Pinguino]

This what I have .... very simple... 39 foot boat...a nominal 8 tonnes..... pix should give an idea of the ratios vane/tab/aux rudder / main rudder.

Works v good, especially good DDW compared with some others, leading edge about 2 inches off the stern. The friend who built it had made about 20 of them , each one sized for the boat it was going on.

Only down side is when going astern.

Cheers,
Frank

[GILow]

Frank,

Those pictures are REALLY very helpful thank you. I note a couple of things with interest, the first being that the trim tab is set well aft and clear of the rudder blade itself, giving much more leverage and allowing the tab itself to be balanced. Good idea.

Also, the SS components seem a little lighter than I had expected, but they are adequate from what you have observed?

Is the dog an essential component? Hard to see from the picture... King Charles? Or do you think it would work equally well with a Schnauzer?

Matt

[charliehows]

Originally Posted by GILow

Hi Matt (great name),

We have a very similar rudder setup to yours. I have not seen trim tabs on an inboard rudder anywhere yet, I suppose because it would be well near impossible to keep the thing moving freely and not blocking up with barnacles etc.

One thing that has been apparent from all of the reading I have done is that there is very little force available from the wind vane itself. CF members like Jim who have built there own often seem to run into problems with drag on the control cables etc, and some of the early systems had simply ridiculous vane sizes in an attempt to overcome this problem. So unless you could think of some way of encapsulating the whole thing in a watertight environment I would say it would be impossible.

I did doodle a design that used a set of very strong magnets rotated inside the trailing edge of the rudder to control the trim tab. I was feeling quite excited till I thought about the effect on the compass. Really glad I did not get around to building THAT particular design.

But, are you considering this because, like me, you find the idea of the big bracket sticking out the back to be a problem? If so, would the pillowblock bearings be a solution for you also? (Seductive picture to follow!)


Matt

From the photo - if you're going to use those type of bearings i'd advise you to look at the equivalent in a self aligning bearing/housing - the ones pictured look like fixed bearings so getting the mounts to align will be a very difficult business whereas self aligning bearings will self adjust. The biggest killer in self steering systems is friction so any miss-alignment stands to doom your system from the start.

[GILow]

Originally Posted by charliehows

From the photo - if you're going to use those type of bearings i'd advise you to look at the equivalent in a self aligning bearing/housing - the ones pictured look like fixed bearings so getting the mounts to align will be a very difficult business whereas self aligning bearings will self adjust. The biggest killer in self steering systems is friction so any miss-alignment stands to doom your system from the start.

Yes, absolutely. Didn't notice those were the non self aligning sort, just grabbed them as they were a nice picture.

Matt

[El Pinguino]

Originally Posted by GILow

Frank,

Those pictures are REALLY very helpful thank you. I note a couple of things with interest, the first being that the trim tab is set well aft and clear of the rudder blade itself, giving much more leverage and allowing the tab itself to be balanced. Good idea.

Also, the SS components seem a little lighter than I had expected, but they are adequate from what you have observed?

Is the dog an essential component? Hard to see from the picture... King Charles? Or do you think it would work equally well with a Schnauzer?

Matt

Last things first.... Harry the Sailor Prince was a dogs' home dog but he could hand , reef, and steer.

The S/S bits that matter are pretty heavy duty. They are all south of the rudder head.... the bits above that essentially just support the vane.

The bearings are at either end of a S/S tube so self aligning....

Its dark here now... I'll get some pics for you in the morning,
Cheers,
Frank

[GILow]

Originally Posted by El Pinguino

Last things first.... Harry the Sailor Prince was a dogs' home dog but he could hand , reef, and steer.

Now THAT is a salty dawg!

Looking forward to more pics too.

Matt