Antoine Maartens wrote:

Seems like you are moving towards Van Loan's geometry!

That's an interesting point. I haven't read Van Loan and I wonder how he justifies his design.

Is moving from 3,6m battens to 4,5 meters battens not pushing it a bit. Chris mailed me the battens on Emmelen91 e are 3,88m.

Yes, definitely. Part of the doodling was to see how long battens would fit.

Moving from 18m2 to 23,3m2 adds almost 30% sailarea. Better make it well reefable!

Isn't that the advantage of the junk rig? I can understand over canvassing being a problem for a Bermudan. I sailed an awful Bavaria in the Clyde that griped terribly in a F5 and had very poor sail shape when reefed. It was effectively over canvassed. But why hold back with a junk sail? Obviously you put your mast and stability at risk, like any square rigged captain, if you put up too much sail. I suspect the Coromandel is under canvassed because Newbridge were marketing a family boat with easy handling.

You are working on 5mm grid paper I assume? So counting the squares would mean the battens would even have to be a bit longer?

Yes, with the boat being 10 squares long you get some useful coincidences which help you sketch quickly. That 10 squares represent 6.2m approx. I don't advise you to take precise measurements from my sketches! I'll scale some of them up and make proper drawings later.

I've wondered about that top triangle, too (years ago), but never tried it on a junk sail, only on a wing sail. There may be some mileage in it, with the kind of geometry that you've sketched. The "yard" would be just another batten, stronger than the normal batten but not so strong as the normal yard. There would need to be a hauling parrel working on the head of the sail.

On Sunday I did some more trials of sailing Tammy Norie with her sail lashed well forward.

Firstly, I improved and tightened my knots around the mast so that the battens were held closer on the starboard tack. I also rigged a downhall on my lowest batten so that i could tighten the sail reefed. This definitely improved that tack, which is usually Tammy's bad track. It seems that allowing the sail to curve away from the mast is bad and reduces drive.

I sailed four tacks from Portsmouth to Ryde in a steady F5 with a moderate chop. I set my wind vane to sail about 70° off. There was a spring current with the wind so I made very little windward progress, which suited my purpose quite well!

I sailed close hauled with the bottom panel reefed. I sailed two tacks with half the top triangle (as described earlier) and two with the whole triangle. There may have been a slight increase in weather helm with the full triangle but there was no increase in speed. Its not clear that the top panel is achieving anything.

In general she made 3.5 to 4 knots steadily with better weather helm than usual. The chop was slowing her down (as usual) but she was retaining enough momentum to keep going. This is an improvement. I would normally expect 2.5 to 3 knots with frequent stopping slaps in these conditions.

There was an increased reluctance to tack. I missed two tacks and had to bear off to gain momentum. This isn't unusual in choppy water, but it did seem worse than usual.

Back in harbour on smoother water with half the top triangle I was quite startled at how gusts seemed to pick her to and surge her forward, rather than just knock her over. It was much closer to the feeling you get from a Bermudan.

Again, very promising and worth a try if you have a similar sail.

@Slieve: Looking at the build quality of my boat - i am inclined to think the builders didn't care too much about this kind of fine tuning. Building small boats and making a profit is quite difficult. I think they had other things on their mind.

As fitting 4 (!) on a 16 foot WL hull being more important than good sailing poperties in conditions most family outings would never encounter.

I think you'll find similar difficulties on other small boats.

@Richard: Great efforts so far. Have you made up your mind up on going with split or aero? Or am i moving to fast?

I am going to fix the luffing problem by fixing the rig, not by modyfing the rudder. This seems to work fine on Emmelene and seems relatively easy to implement.

On the outboard being on one side of the Coromandel. I had planned to lift it further out of the water but shyed away from that because I was strongly advised to keep the stern in tact and not interfere with it. For now I opted for a very small engine.

IF the sail fix works, Siskin will be only need a very small steering arrangement - might even be only a piece of rope. Maybe not needing a big heavy device like an Hebredian or similar.

Slieve McGalliard wrote:

Now if taking the brakes off by moving the rig forward a little has improved the performance, just think what might happen if you also pressed the accelerometer by adding some camber (drive) to the rig. Keep up the good work

I'm heartened that a combination of sail position, camber, and mast rake will be enough to get everything I want without rebuilding my rudder. That may happen anyway one day — Coromandels have problems with their rudder tangs eroding.

It might be with noting that I was already playing with the sail position within the limits of the original design, but it may just not have been enough.

It's too early for firm conclusions, but this is quite exciting.