Calming my windvane down....

[webcraft]

I have a Navik on the Vega and a Navik on the Morgan Giles 30 I am currently sailing. I have motor-sailed using the vane with both boats, but under power with the blade down there is more vibration of the vane with the Vega than on the MG in spite of the MG having a bigger prop. This is, I think, because of prop position. On the Vega the prop is aft of the rudder and close to the water paddle, on the MG it is several feet forward of the paddle and in a cutout.

Long story short, try motorsailing or motoring with the vane working and observe the water paddle. If it is vibrating like mad then maybe don't do it for too long. Short sessions are unlikely to harm it in any event.

Re. oscillations... it is much easier to set the vane up if you can get someone to steer a course as you set the vane up. If single handed then it may be necessary to adjust tiller line tensions 'on the move' until the vane stays mostly upright and the paddle swings evenly from side to side around a central point. If the vane/paddle spends most of its time over to one side then tighten the opposite tiller line.

Some easy method of tiller line adjustment is necessary. I use cam cleats on the tiller, others seem to prefer chain hooked onto a pin.

- W

 

[Driftingby]

Thanks to all those who offered advice and suggestions. I’m pleased to report it all moves easily with no slack. I’m less pleased to report I had managed to break the link between the vane down rod and the rudder gear set, so a call to Sea Feather on Tuesday is needed to source a replacement as the plastic used doesn’t like epoxy or CA...
Feeling confident I can get it working once that is replaced

Chris

 

[roaringgirl]

If everything is set up correctly, you should be able to steer the boat by moving the vane sail as though the wind were blowing it over as the boat comes off the wind in either direction. I would start by trying this and then figuring out why it isn't possible.

 

[Blueboatman]

Roaring girls suggestion is a good one.

AFTER OF COURSE ENSURING THAT THE UPPER VANE HAS NOT BEEN INCORRECTLY MOUNTED 180 degrees out. ( As also suggested earlier ), photo proof would be useful .

1. Try steering the boat by pushing and pulling the windvane with one finger, does it resist mightily , does it all respond smoothly or jerkily when actually sailing ??

2 . is the paddle actually set up vertical in the water ? If it’s foot is inclining too far forward of the vertical then the thing is INHERENTLY unstable and will be trying to wander to one side or the other all of the time..!
Which is ‘’Oversteer”, which is what you are describing in its behaviour thus far)

3. You might try furling the genoa away and just gently sailing on reefed main. If the boats helm is light to the touch now when hand steering, then there is no reason for the vane to be anything other than light and rock steady as well.

My ‘money ‘ is on
A/ checking/eliminating poor vertical alignment of the paddle and then
B/ a disintegrating /sticking main bearing action on the horizontal shaft about which the whole unit rotating. when actually being asked to work under ‘at sea ‘ conditions ..
before
C/ delving down into the smaller working parts and linkages clicking sticking and binding up under load.
Do let us know how the tests go!

 

[Buck Turgidson]

Roaring girls suggestion is a good one.

AFTER OF COURSE ENSURING THAT THE UPPER VANE HAS NOT BEEN INCORRECTLY MOUNTED 180 degrees out. ( As also suggested earlier ), photo proof would be useful .

1. Try steering the boat by pushing and pulling the windvane with one finger, does it resist mightily , does it all respond smoothly or jerkily when actually sailing ??

2 . is the paddle actually set up vertical in the water ? If it’s foot is inclining too far forward of the vertical ( like a folkboat rudder viewed side on) then the thing is INHERENTLY unstable and will be trying to wander to one side or the other all of the time..!
Which is ‘’Oversteer”, which is what you are describing in its behaviour thus far)

3. You might try furling the genoa away and just gently sailing on reefed main. If the boats helm is light to the touch now when hand steering, then there is no reason for the vane to be anything other than light and rock steady as well.

My ‘money ‘ is on
A/ checking/eliminating poor vertical alignment of the paddle and then
B/ a disintegrating /sticking main bearing action on the horizontal shaft about which the whole unit rotating. when actually being asked to work under ‘at sea ‘ conditions ..
before
C/ delving down into the smaller working parts and linkages clicking sticking and binding up under load.
Do let us know how the tests go!

err... can you show the maths?

Transom hung rudders are hinged in front of the leading edge. Stability in a control surface is dependent on hinge moment and moving the hinge line forward increases stability regardless of hinge relative angle to the flow.

 

[JumbleDuck]

I have a secondhand windvane (Sea Feather) that I have fitted to my Sadler 25 as I sail alone mostly and would like to sail all day without having to steer all the time.

It all seems to work, apart from the fact that when connected up to the tiller, the boat swings in a 30-40 degree arc from side to side.

My boat came with a Sea Feather which has now been out of use for year because, although it was a thing of joy to watch when working, it was bloody near impossible to get working. The particular vice mine had was for the wind vane to flop over to one side, the water vane to twist and swing and the boat to turn nowhere near enough to return to the set course.

I consulted the original makers of the Sea Feather and they recommended (a) flexible control lines (b) tweaking the amount of slack (c) carefully balancing things out, by reefing if necessary, to reduce tiller input to a minimum before engaging the SF.

I never got round to it for sound practical reasons. This summer I decided to have aproper go at it again, but the weather for my abbreviated two week jaunt round the Clyde wasn't good enough. I'm planning to give it one last go and if I can't get it working reliably, sell the thing.

The company has been sold since. The new people are friendly but take four months on average to answer e-mails.

 

[JumbleDuck]

Much slack on the non-pulling side with the tiller over will cause all sorts of errant behaviour, and this is down to poor geometry of the lines' setup)

When I asked about setting up mine I was told that in normal use the upwind side should be tight and the downwind slightly slack - in other words, the Sea Feather should always be working against a slight weather helm. In even otherer words, the Sea feather should do any turning into wond and the boat should do any turning away from the wind.

 

[Blueboatman]

err... can you show the maths?

Transom hung rudders are hinged in front of the leading edge. Stability in a control surface is dependent on hinge moment and moving the hinge line forward increases stability regardless of hinge relative angle to the flow.

Correct. Thanks. My bad.
Reference to ‘raked fixed rudders-like a folkboat- and hinged at their leading edge’ is now removed.
But , the oversteer argument will still be valid in this case -if the blade is at all forward inclined when in the down position then adverse turning moment is put in to the equation, how much will of course depend on the area, degree of of rake..
I think we both know all this too !
my poor example,

 

[mattonthesea]

I have an Aries but the principles are probably the same. My vane axis is about 30 degrees to the horizontal with the upper end as the wind facing end. It means that the off wind effect is very quick. During use the vane will flip from side to side quickly and quite a lot. But by the time this translates to tiller/rudder movement it has damped down to very little. I know that it says to have no slack in the lines but I find that this can help damp the movement too. I would have the tiller attachment further forward than the tiller pilot (that's from experimentation).

The only time I have had arcing like yours is when I had a lift-up version of the Aries. It's counter weight was so paltry that I had to make an extra long vane out of corex.

 

[Driftingby]

After all the excellent support and suggestions it seems rude not to provide a progres update - after Sea Feather returned from their sumer break (which of course coincided with me finding the broken link) they have been extremely commuinicative and helpful and a new spare is on it's way. Assuming it arrives in time for the weekend, I plan to be down to fix and test and will report back in due course.

 

[Driftingby]

Pleased to report that the part arrived in Saturdays' post, so was duly fitted today and a test sail completed. No veering +/- 20 degrees, so my conclusion is I almost certainly had the wind vanve facing 180 degrees.......

Wind (according to Bramblemet) was 8-10knts at the time I was testing and I could get it to keep the course for 5 -10 mins, before it would drift off - is this due to poor sail balance, or not enough wind for the vane??

Thanks again to all who contributed ideas and auggstions,

 

[SteveAus]

8 - 10 knots wind should be fine for windvane steering.
I presume when you refer to the course, you mean the course relative to the wind, not the compass course, as obviously the compass course will change if the wind changes direction.
When you say it would drift off course after 5 - 10 mins, do you mean it would drift off and not be corrected by the windvane, or drift off temporarily and be brought back on course. If the former, there is still something wrong.

 

[Carib]

It's not clear how old the OP's gear is, but it might be worth noting that early Sea Feathers look nothing like the newer Sea Feathers. They've gone through a lot of refinement over the years.

 

[webcraft]

Interesting to read about the vane being set 180 degrees out. I have a Navik on both my boats, have been using it on the Vega since 2006, and have never done this. Until the other day, going downwind on Avy-J. Baffling. I had to give up and hand steer until the penny dropped an hour or so layer.

- W

 

[Driftingby]

Thanks SteveAus - the issue was it would not correct and come back on course, with the rudder blade stuck over to one side. Not had another chance to play since, but might have one last bite at trying this coming weekend if the forecast develops as promised.
To Carib's point, I believe this is one of the very earliest designs, but am sure it should still work... I've obviously got some more experimenting to do.

 

[yimkin]

I too have a Seafeather and initially mounted the wind vane incorrectly!! possibly in the 180 degree attitude. I have since traced the outline of the vane connection on the vane so it is easy to see it is correctly connected.
I find it holds a good course but unless I am clear of land effects I have to adjust for course drift as it obstinately follows shifting wind patterns!
I generally sail singlehanded and I really rate my Seafeather and wish I had bought it years ago. My main concern is potential damage in the marina either by my maneuvers or by others

 

[SteveAus]

Driftingby,
If the windvane's rudder is stuck over to the side, then the boat's tiller should be well over to the side. If this has not brought the boat back on course it suggests that either the sails are very badly balanced or the boat's tiller is not far enough over to the side. The latter can be corrected by moving the point at which the chain attaches to the tiller nearer to the rudder stock.

 

[Driftingby]

SteveAus,
That was my thoguht and I'm sure the sails were well (enough) balanced, so will play with location of the chain attachment point. Having bought the device secondhand with no instructions (although since kindly provided by Pye End) installation of the tiller connection has been guess work and I've just used the existing tillerpilot connection. Based on your comments I will now experiment with moving the connection.
One final question - the blocks to turn the line are currently behind the connection point on the tiller (by 10cm or so), is that likely to cause a problem?

 

[MM5AHO]

I have a Seafeather (on a Rival 32). I have noticed, that when I was not thinking about the setup, that putting the wind vane (sail) 180degrees out the unit doesn't work, and swings all over the place.
I have also noticed that the whole mechanism needs to be free, and this requires service. I do that myself, disassembling the unit in winter, cleaning all the mating parts (they get crusted with salty residue), and lubricating with (white salt water use) grease. Reassembly (watching that where ny-lock nuts were used that there's still enough locking avaiable) is just the reverse, but the whole mechanism seems to need this annual cleanup. I changed the nylock nut on the bolt that secures the rudder (blade / oar/ ?) to the yoke in which is sits, to a standard nut with a split pin (I drilled this). This saves me carrying spare nylock nuts onboard. I nearly lost the rudder once when the nylock came off and bolt started moving through.
Next is the setup, but as others have noted, your huge swings suggest something other than setup. I have noted in ther past an oscillating tracklog on my plotter is able to be straightened out by tweaking. Tweaks include moving chain attachment point to the tiller; positioning the wind vane slightly off the wind at times. (I have continued having a ribbon telltale in the trailing side of the top of the vane), and the like.
Mine goes best when there's a little (not excessive) weather helm - so I adjust sails a little between my main and 140% genoa to get some. A perfectly balanced tiller works, but not as well I find.

 

[SteveAus]

Driftingby,
10 cm sounds about right for the block location. I presume that the blocks are on the side coamings, so a long way from the tiller.
Regarding the location where the chain connects to the tiller, I would expect the distance from connection point to rudder post to be 1.5 times the distance between where the rope attaches to paddle arm and the pivot point of the paddle arm.
When the paddle arm is at 45 degrees, the tiller should be about 30 degrees off centre.