Placement of Windvane Steering System.

[El Pinguino]

Photos as promised.

First pic.... the bit that is attached to the boat... 60mm o/d... 25mm hole down middle, bearings top and bottom
Next... 25mm solid pin that drops down inside previous bit and secures whole thing to back of boat....short tiller has (red) damping lines attached... they go through turning blocks ( see previous pic) and then into jammers on transom.
#3 The push pull arm between vane and trim tab.
#4 Bit of tube that carries 'signal' from vane to trim tab. Bearings top and bottom secure the bit that rotates and has a lever attached to the bottom end.
#5 the top of the aformentioned tube which has the 'on/off' gear on it. Pull on red string from cockpit... disengages... release string and the bungee locks vane to downstream bits. Handle on end of worm drive allows fine tuning when engaged.
#6 detail of vane showing bit that engages with worm drive.
Cheers,
Frank

[Normanby]

Nice looking bit of kit Senior Pingiuno.

To answer your question Matt, yes, my interest in trim tab systems has much to do with simply not wanting all that precarious scaffolding hanging off my lovely stern.

My favourite view of boats, aesthetically, is from astern. Same with cars and women...
Thus i like my view unimpeded...

I've dreamed about the self-contained auxiliary rudder systems, and wondered if one could be installed THROUGH the transom, in some kind of custom designed hole, with a plug for when not in use.

The South Atlantic springs to mind. It looks neat and self-contained, but at least one CF member customer has complained bitterly about build quality and after-sales service.

[GILow]

Originally Posted by El Pinguino

Photos as promised.

Frank those are really helpful photos, thank you. I take away a lot of thoughts from looking at them.

The first is that it is a much bigger blade than I had been expecting, which ties in with Jim's comment about the depth of the cord. My sketches were rough, and way too small, but probably I was subconciously revealing my thinking by the way I drew things. I need to go back and look at my design a bit more carefully. I was planning for a longer blade with a short cord, but that may not be the way to go and may reveal my over exposure to aircraft design.

The 1" pintle was a bit smaller than I expected, but I clearly it is holding up ok, so maybe my 1.5" idea is overkill... not sure, bit to think about.

I really loved the worm drive adjuster, that's just plain elegant and it solves the adjustment problem far more neatly than anything I had envisaged.

Your point about the problems with reversing reinforces my desire to make ours easy to pivot out of the water when not in use, and I will continue to keep that as a key requirement, we are simply too hampered in our movement already to start introducing any other variables. Ann is right in noting that the aux rudder can help, but I need to have a CHOICE in the matter with our boat.

Thank you again for the photos and effort you made to get them, I really appreciate the help they provide.

Matt

[GILow]

Originally Posted by Normanby

Nice looking bit of kit Senior Pingiuno.

To answer your question Matt, yes, my interest in trim tab systems has much to do with simply not wanting all that precarious scaffolding hanging off my lovely stern.

My favourite view of boats, aesthetically, is from astern. Same with cars and women...
Thus i like my view unimpeded...

I've dreamed about the self-contained auxiliary rudder systems, and wondered if one could be installed THROUGH the transom, in some kind of custom designed hole, with a plug for when not in use.

The South Atlantic springs to mind. It looks neat and self-contained, but at least one CF member customer has complained bitterly about build quality and after-sales service.

I had briefly looked at the South Atlantic. I didn't read the CF complaints, but my gut feeling was that it was a really complex little mechanism that probably worked brilliantly for a while but would age horribly, given all those small moving parts. The people who seem happiest with systems over a few years old all seem to have really blocky, simple devices that are not particularly attractive to look at, but are mechanically very simple.

I totally agree with your aesthetic values on the other matters, though sadly, I can't really say the S42 is most attractive from the stern.

Matt

[El Pinguino]

More pics as promised.... the beast in place on our return from Iquique the other week...

First pic shows general arragement.
#2 the head gear... outer tube fixed in relation to the aux rudder, carries 2 bearings and the tube that actuates the linkage at the bottom.
#3 the vane in situ.... disengaged it can just follow the wind as it wishes.
#4 bungee is used to engage the vane, screw thingo at back stops vane falling out if knocked down. Red line leads to helm... used to engage/disengage vane.
#5 Inner tube shown at #2 has a lever at bottom which in turn is connected to the trim tab.
#6 damping lines lead from stub tiller through jammers. Shown hauled off to stbd here to give better access to ladder. Normally tightened down quite hard to limit movement of aux rudder to about 5*.

Main helm lashed with maybe a few degrees of weather helm as required. Works best with headsails doing most of work and the main depowered a bit.

Thats it... I have a boat to get ready for sea...toodle pip

[GILow]

Originally Posted by El Pinguino

More pics as promised....

#4 bungee is used to engage the vane, screw thingo at back stops vane falling out if knocked down.

Those are truely inspirational pictures, and enough to make me wish I had a transom hung rudder.

I particularly appreciate the concise use of technical language, it made it much easier for me to understand the function of various components...

When my wind powered rudder whatsit is completed, I too will post pictures... probably about two years from now on present rate of progress...

Matt

[El Pinguino]

Originally Posted by GILow

Those are truely inspirational pictures, and enough to make me wish I had a transom hung rudder.


Matt

The rudder is a spade.... top of trailing edge in line with lower edge of stern... rudder post is about 6 inches in from the back end of deck....

[GILow]

Originally Posted by El Pinguino

The rudder is a spade.... top of trailing edge in line with lower edge of stern... rudder post is about 6 inches in from the back end of deck....

Ah, sorry, I see it now. It was so substantial I thought it was the main rudder.

Perfect. Exactly the principle I am trying to put together for our boat, with, of course, the complication of the canoe stern and being offset to one side.

Matt

[Terra Nova]

Keep it on center.

[GILow]

Should work fine off centre, maybe not as well as centralised, but nothing to worry about. Most of the aux rudder windvane manufacturers support their system being used off centre.

Matt

[Rustic Charm]

Hi guys,

I have a 36 foot steel ketch, which weighs around 10 tonne. It has a large tiller rudder hanging off the transom. I'm looking at making a trim tab on the back if the rudder to which you pin the main rudder in place. I'm then planning on using an autohelm upper unit to connect to the trim tab. Given the trim tab width is only about a 1/10th of the width of the rudder, does such a thin trim tab actually manage such a large boat?

[El Pinguino]

Originally Posted by tedsherrin

Hi guys,

I have a 36 foot steel ketch, which weighs around 10 tonne. It has a large tiller rudder hanging off the transom. I'm looking at making a trim tab on the back if the rudder to which you pin the main rudder in place. I'm then planning on using an autohelm upper unit to connect to the trim tab. Given the trim tab width is only about a 1/10th of the width of the rudder, does such a thin trim tab actually manage such a large boat?

Check post #25 in this thread... that should give a good idea of the ratio between tab and rudder.... nominal 8 tonne 39 foot boat...works good,
El Ping

[Rustic Charm]

Originally Posted by 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

Hi,
Doesn't the empty space between the trim tab and the rudder create an unecessary place that the rush of water would interfere with the flow?

[El Pinguino]

Originally Posted by tedsherrin

Hi,
Doesn't the empty space between the trim tab and the rudder create an unecessary place that the rush of water would interfere with the flow?

Doesn't seem to bother it... in fact allows clean water flow over both sides of the trim tab.... probably works all the better for it...

[Rustic Charm]

If a 4 inch trim tab can turn a ten ton boat, why do they design the boats with such big rudders? Mine is about 18inches in its width.