David Tyler wrote:

Chris Gallienne wrote:

Often thought Jester would suit a split rig - same planform, just cambered and split:

Same planform, cambered and split - OK. But please, scaled up to at least 30 sq m!

I agree with David  -  that is I  -  would like to see two versions:

For the sake of science, one should first make a 22sqm split junk version, just to demonstrate what the split and camber did to the sail.

Then, for the sake of fun, one should make one at 30sqm  -  at least!

Arne

David Thatcher wrote:

  I don't think camber makes any difference in speed once the wind is 70 degrees off the bow, so added sail area might help there, although I see that as less important since the rig is very powerful when the wind is free. 

I can say without any doubt that the camber in the sail on Footprints adds a tremendous amount of power in reaching conditions. The boat is significantly faster than with the flat sail. This might also have something to do with the low aspect ratio of the sail as opposed to a higher aspect rig (?) 

C A Marchaj showed many years ago that low AR sails are better than high AR sails, downwind.

  I don't think camber makes any difference in speed once the wind is 70 degrees off the bow, so added sail area might help there, although I see that as less important since the rig is very powerful when the wind is free. 

Annie Hill wrote:Wouldn't it be great if Trevor Leek put either an Ingerborg rig, or David's improved sail on Jester, to see what a difference it would make?  If Jester would perform anything like Arne's and David's boats, it would do a lot to make people realise what a realistic alternative junk is to bermudan rigs.

Wouldn't it be great if Trevor, and therefore Jester, were in the JRA?

Mast position may be another issue.  I have come to the conclusion after sailing Arion 2000 miles at sea with my new flat sail that I have more weatherhelm now when broad reaching and running.  The centre of area is the same as it was for my cambered sail but I suspect that the centre of pressure of a cambered sail is further forward.  On the flat sail it is in the same place as the centre of area but on a cambered sail I think it may trend towards the point of deepest camber, which on Arion would put it about 500mm further forward.  Unfortunately, my sail is already as far forward as I can get it so I just have to reef earlier downwind.  That's ok, as, like Roger Taylor, I like to keep things soft and gentle, reducing stress on rig and crew.

Still, it would be fun to see Jester screaming around with a big rig, although Trevor might disagree!

Iain, that's the length that I've used.