Many thanks for all the comments.  Very interesting that Samson's sails are fine, but Zebedee's and La Chica's flap. .I think the following were big factors in Zebedee.

The sail's chord is 2 inches longer than the batten, so quite slack.

The pocket stops 3 inches short of the luff, unlike the foresail where the pocket goes right to the luff

The bolt rope is too tight causing slight puckering.

In stronger winds the sail between the pocket and the luff seems to bag.

I cut 2 inches off the luff and re stitched the bolt rope. The pocket now comes to the luff and the sail is reasonably taught (not very tight tho) along the batten. Last week I sailed against the wind in about 20-25 kts, 2 reefs in the main, none in the fore. (In lighter winds no reefs and no problems)

Huge improvement in the stronger winds, less weather helm too. The luff still lifts very slightly, but the fore starts to lift just after, so it's as close to the wind as we can go.

The fore sail still has the extra 2 inches of chord,but the pocket stops the bagging at the luff. 

I think it's best to have the mainsail tight along the batten, just as described in Samson. It reduces the camber but maybe that's a good thing with the main.Having the pocket right up to the luff is also helpful.

Arne Kverneland wrote:

Alan,

in case the mainsail’s bagginess at the luff causes it to lift early, is the problem the same on both tacks? As can be seen on this photo of Samson, with the sail on the weather side of the mast, the bagginess is much restricted by the mast.

How about the shape of the foresail’s camber near the leech? Is it nice and straight or is there some ‘hook’ in it? It is well known that blown out and baggy old staysails tend to make the mainsail lift early.

I should like to hear Paul J T’s experience with the JR of his schooner-rigged La Chica on this matter.

Arne

LC has similar problems to what Alan is reporting. The foresail (with 12% camber, max at 35%, entry angle 8%) sets perfectly and like Alan, I regard it as a real work horse. I do not think that it has to much camber.

The main (with 10% camber, max at 35%, entry angle 8%) works just fine once the sheet is eased but when close-hauled and wind speed over F3-F4 I also experience the luff collapsing. For this sail the luff is 4 layers of mustang (starting at 200mm with last layer 50mm) Have to admit that I have not tried using a downhaul on the luff yet.

I have considered flattening the sail but decided to wait until I've built my new ruder (that's done now, some photo's in my member album) as I did not want to change more than one major item at the time.

I suspect that the foresail is interfering with the main. Sheeting the main harder may fix it but with the old rudder, that resulted in a great deal of weather helm. When I made the new rudder, which is also repositioned further aft and vertically so as to maximize efficiency and move the CLR as far aft as possible, things should be much improved.

If that still does not get things right, I may have to flatten the main a bit but I'm reluctant to do that as LC is a heavy boat and needs all the power she can get. On the other hand... if the main is not able to work properly, then flattening it and being able to sheet it right in may be just what is needed.

Alan, 
another two questions:

• Have you actually measured the camber with the sail flying, like this (remember to subtract the batten thickness)? 
• When you lofted the batten panels and created the Round (barrel shape) along the battens, did you use a wooden spline to create that curve?

I ask the last question because that is how I do it. This use of that wooden spline results in a fairly straight curve of the Round at the luff. Still, it appears that there is more curve in the finished sail. In other words, I see little reason for torturing the spline  into a sharper curve at the luff to get the sail camber right.

Alan,

in case the mainsail’s bagginess at the luff causes it to lift early, is the problem the same on both tacks? As can be seen on this photo of Samson, with the sail on the weather side of the mast, the bagginess is much restricted by the mast.

How about the shape of the foresail’s camber near the leech? Is it nice and straight or is there some ‘hook’ in it? It is well known that blown out and baggy old staysails tend to make the mainsail lift early.

I should like to hear Paul J T’s experience with the JR of his schooner-rigged La Chica on this matter.

Arne

 

Alan B Martienssen wrote:

Hi Arne,many thanks for the your reply. The problem has always been there. The main is now 6% camber. I have fitted a downhaul and it did help a little. But as the wind increases, the flapping becomes worse, extending including the forward third of the sail. I seem to sail faster and closer without the mainsail!

Gday Alan

Can't say I've seen the same phenomenon on our Badger. We've just completed 400Nm of wind on the nose, tacking back and forth for 2 weeks, but only F2 to F3, we managed around 30 Nm/day made good, which I thought was quite acceptable. (Boats going the other direction, downwind, were with sails furled and motoring! They probably subscribe to the rule; under 3 kts switch on the power..)  I find using the main is quicker to windward than without, in lighter winds anyway, better balance helps pointing closer to the wind too. Also I found with schooners, the main is supposed to be sheeted in closer than the foresail (an argument for less camber in the main too), but some slight flapping only occurs when luffing. We use a Raymarine Tiller Pilot now, which does a sterling job of holding the course with weather helm.

Our foresail has 7.5% camber, the main 6%. Maybe the foresail would be better off with 10% but that would mean more distortion with the lazy jacks digging into it, so I wonder if it really would help much.

On the final day into here, Gove NT, we had a dream run, hard on the wind, 4.5 to 5.2 knots most the way. Only spoilt by some big bermudan who raced past us as if we were standing still. A 45 footer, holding at least 6.5 knots on the same 45˚ off apparent wind. Amazing what an extra 12' of WL and one less mast gets you..