Stavanger, Friday
Thierry
You asked:
"the vanging effect has a forward component along the battens. How big is that force when running?"
I don’t think that will be a big problem, in particular not in your boat as you cannot sheet out the sail that much because of the shrouds. In Practical JR Hasler and McLeod warn against compression in the battens if you square out the sail too much, that is, past square.
You asked:
set of light downhauls at the mast, Each downhaul handles two battens.
"Are they there to keep the luff tight or to help when reefing?"
Both. I thought they might me useful in ensuring that the junkette sail would not stick when lowering the sail and it also ensures that the luff of the lowest panels sets straight. I have fitted downhauls to my Johanna recently, just as a test. Johanna’s sail comes down without help, but a light tug on the downhaul stretches the lowest luff (probably more for the looks than for the performance). These downhauls are easy to deal with and don’t add much friction when hoisting the sail.
Arne