See, lot's of helpful advice!

I have just had a look at a plan profile of your design that I have and it seems to me that with the designed cutter rig there is a lot of sail forward on the boat, even a bowsprit. Whereas in the photo of your boat you have a lot of sail well aft on the boat with that low aspect sail and the very long battens. So I would recommend trying to get the CE of the sail a bit further forward and see if that makes any difference to your tiller loads. If you have some means of moving the whole sail forward on the mast, and this might just be a matter of changing the position of the batten parrels, this would be a good experiment. If you cannot do that for the whole sail, allowing the lower part of the sail to swing forward on the mast would help to achieve the same result. If you have a look at the new sail pics in my profile there is a photo there of my sail canted well across the mast when sailing off the wind. This used to lighten the tiller loads and weather helm a lot on my boat with the low aspect sail, although with the redesigned rudder canting the sail across the mast is not so necessary.

David Thatcher wrote:

I also doubled the amount of balance area on the rudder on the section which extended below the skeg, and I built the blade to a proper NACA foil profile. 

Not an easy option.  The rudder does not extend below the skeg, and there is no balance area.  The skeg has only a little less draft than the keel.  If I extend the rudder below it, I risk ripping it off if (or when, according to many with more experience) I ground.

However, you made me realise that there is something I overlooked.  The skeg is a flat plate with rounded edges.  Seeing that either an end plate or an articulating rudder would increase lateral loads, I was considering strengthening the skeg by building it up to a proper foil profile, which would be thicker.  That might actually help in itself.  If improving the skeg's profile gives it a higher lift coefficient, then the centre of lateral resistance will move aft, and there will be a little less load on the rudder.  The drawback is the risk of lee helm in lighter wind.

David Thatcher wrote:

Paul Thompson on La Chica also had similar rudder problems and built a new rudder which dramatic improvements. He may comment but he did write an article about his experiences a couple of JRA magazines ago.

Thank you.  I will look that up again.

Asmat Khan wrote:

The Kingfisher 26 "Chopsticks" was reported to be suffering from excessive weather helm after being fitted with a cambered rig a few years ago. I was in the final stages of converting my "Antares", a sister ship, also with a cambered sail, when I learned of this problem. With launch day fast approaching, I added end plates to the rudder and to the skeg, about 4" wide as far as I can recall. I found that under sail, she was docile and well balanced. Whenever she began to gripe, dropping a single panel restored good manners. Off the wind, hauling the sail across the mast to weather helped to maintain fingertip helm forces.

To be sure I understand, you didn't sail Antares with the junk rig, but without end plates?  Do you know whether any modification was made to Chopsticks that improved the situation?

You will no doubt have all sorts of comments on this but your situation sounds very much what I have gone through with my own boat. I can offer some observations. My boat has low aspect fan shaped camber panel, sail not unlike the shape of yours based on your boat's photo. This was a new sail 3 years ago to replace the traditional Hasler shaped sail. When the new sail was first installed I had terrible weather helm, although the boat always did respond to the rudder. I ended up raking the mast forward by 3 degrees to bring the center of effort of the sail further forward which helped the weather helm situation a lot. However I still did need a lot of rudder angle and still had very heavy tiller loads. Last year as a result of damage to my boat during a storm, and then the subsequent discovery of rot in the rudder I ended up building a whole new rudder. With the new rudder I took 100mm of the trailing edge of the rudder so the new blade was now 400mm wide instead of the 500mm of the original rudder but I added 70mm (to a depth of 500mm) to the leading edge of the blade to fair the blade into the skeg where there had previously been a gap. I also doubled the amount of balance area on the rudder on the section which extended below the skeg, and I built the blade to a proper NACA foil profile. The changes resulted in a dramatically different helming experience with very little or no weather helm, very small tiller angles needed to maintain a course and overall a much more enjoyable sailing experience.

So my suggestions are that you could try reducing heel angles by reefing earlier. If you were able to cant the lower part of the sail forward across the mast, particularly when off the wind which will have the effect of moving the center of effort of the sail forward which might make a difference. If none of the above solve your problems you may need to look at changes to the rudder to make it more effective and this would certainly start with a proper NACA foil, and maybe a deeper rudder with more balance area. Going to an articulated rudder or similar will just add unnecessary complication.

Paul Thompson on La Chica also had similar rudder problems and built a new rudder which dramatic improvements. He may comment but he did write an article about his experiences a couple of JRA magazines ago.

Arne Kverneland wrote:

Anyway, a rudder angle of 20 - 30 degrees when sailing closehauled, makes me wonder if you have got the lead right.

Not only the rudder load, but also the rudder angle required to keep the boat on course varies drastically with wind strength.  Part of that is likely to be the lateral offset between the sail's pull and the hull's drag that I get from heeling in stronger wind.  I attribute the large rudder angle needed when broad reaching without heel to hitting hull speed, and therefore the rudder's effectiveness no longer increasing with wind speed.  

I was unsure about replacing my flat sail by a split junk, on the grounds that the mast looks to be too far forward and I worried about lee helm.  In light winds, there is hardly any weather helm.  A cambered sail should move the centre of effort forward, which might reduce or cure the rudder load problem, or else the boat might change from lee helm in light wind to not as strong weather helm in stronger wind.

I still would like the boat to respond more promptly to the rudder, which is why I asked about rudders, but if a new sail can help, that will be easier and cheaper to make happen than a new rudder.

Two years ago, I bought Gecko, a junk-rigged Benford Dory 26, Badger's little sister.  She has a large skeg and a comparatively small rudder (the rudder on my 14ft Paradox was larger).  A few days ago, we had 15 knots of wind for the first time since I got the boat.  At 20-30 degrees heel on the wind, I needed 20 degrees rudder to keep her on course (I measured it).  On a broad reach, with the sail about perpendicular to the boat and no heel, I needed the same rudder angle.  I was not using the batten parrels to haul the sail back towards the mast, but neither was I using a vang to pull the sail in.  The load on the tiller was good exercise, but an autopilot or a wind vane may have to be a bit oversized to cope.  Also, I have not nearly as good control when reversing under engine as I would like.

What are the experiences of Badger owners?  I remember someone gave a Badger a balanced spade rudder.  I expect helm balance changes more with wind on a single sail boat.

I can think of the following modification to make the boat respond to the rudder more and to reduce tiller load:

1) Put an end plate on the skeg that stick out far enough aft to close off flow around the rudder tip.  Preventing that flow should increase effectiveness, but would also increase rudder load.

2) Put a flap on the trailing edge of the rudder, to make an articulating rudder:

http://www.georgebuehler.com/Articulated%20Rudders.html

and

http://www.bayviewengineeringind.com/Rudders.html. 

That would increase control, but increase tiller loads even more.

3) Hang an additional pair of balanced rudders on the transom, on either side.  If tehy are perfectly balanced, then they increase control, and should reduce tiller load a little because the skeg-hung rudder can take less of the load.  There would be some redundancy in that is any one rudder fails, I would still have enough control to get home.  A drawback is that the extra rudders would not be protected by skeg or keel.

4) Replace the skeg and rudder by a balanced spade rudder with the same draft and area as the current skeg and rudder combined.  With a good wing profile, that should have a larger maximal lift coefficient than two flat plates.  It is also likely to be the most expensive solution.

Any comments?

Webmaster edit:

Robert, I have reformatted this post to stop it spilling off the edge of the frame.