It is amazing the "new" ideas that we find in "old" places.

I was reading up on batten design in PJR, and ended up in a discussion of how the sail scallops a bit in the breeze and what effects it has.  Then I read this sentence: (pages 16-17)

"It would be possible to cut a sail with this fullness built into each panel, thus achieving more arching in ghosting weather without requiring the battens to bend at all, but the implications of this would have to be studied empirically on a full-sized boat."

Arne, I don't know if you noticed this before you started making your sails like this--it is easy to miss or forget about one sentence like that.  In any case, thank you for doing the empirical studies on a full-sized boat!

Once again, I'm very impressed with how much the Hasler & McLeod would write about what they had decided to do and why....but left in little mentions like this more-or-less saying "We haven't tried this, but it could be worth looking at" sprinkled throughout.

And I wonder what other gems well worth trying are hidden away!

Barry

Stavanger, Thursday

              .. the slow rate of newsletters..

I wonder for how long that Insect Flight Theory would have lasted if today’s internet had been around in the early nineties. The flow of information through the newsletters was appallingly slow, so a meaningful debate was not really possible. Just look at the numbers below.

I received...

.. NL30 in September1995 containing info as old as from Oct. 1994...

.. NL31 in July 1996 containing info as old as from Mars 1995...

.. NL32 in December 1996 containing info as old as from Jan. 1995...

... etc, etc...

In practice this meant that when I sent in a reader’s letter about Malena in Dec. 1994, I would not be able to read any comment about it until July 1996 – 1½ year later! Now, there were never any comments, but I got many encouraging letters directly to my home address. Guess why.

I remember I had two ideas about this:

So this forum is definitely a big step of progress – it lets ideas fly faster...

Cheers, Arne

PS: Maybe this internet forum is too fast and that the noise from all my writing hinders others from working out new ideas – ouch, that would be bad!

Kurt Jon Ulmer wrote: Thanks to Ketil, David & Arne, Bunny and Vincent.

I'm motivated to spend some hours perusing JR Newsletters. I have a few on paper, and borrowed a set once while contemplating the rig. Now there's a thick stack of .pdf ones available to me, and I'm grateful!

Kurt

Bunny Smith most certainly achieved a lot. His big mistake was he changed to many things at once, so he could never really tell which item he changed was actually the beneficial one. His other great mistake was that he was to busy trying to make the facts fit his theory and this blinded him to the many hints to where he should have been looking. None the less by shear bloody mindedness he got to where he was trying to go, even if he never really understood how he got there.

Stavanger, Christmas day, before going to another Christmas dinner party...

I think Ketil is right here. During Bunny Smith’s experiments he changed 2 parameters; fitting both "turbulating " keep battens and bendy battens. Credit for the improved performance seems to have been given mostly to the Insect Flight Theory. Alan Boswell had an article about this in NL 25, p.39.

Bunny then did another thing that I think was very clever: He fitted a leech line between the tip of the yard and the tip of the upper batten and thus introduced camber in the top panel (see NL23 p27). The effects of twist in the fanned sail were mainly discussed by Vincent Reddish (NL 22), I think.

Like David, I too think that the top section of a fanned sail produces a lot of drive. I have tested Johanna’s sail in a god Force 7 (inshore) with only the 3 top panels up, and the boat went like a witch, tacking and manoeuvring just like in a breeze with full sail set. During the rally in August I surprised both the crew and myself by demonstrating the power of these 3 panels in a medium F4. Johanna remained quite close-winded, maybe 5° worse than with full sail up. On a beam reach we were only a decimal from touching 5kts with those 21sqm on a 3 ton boat. On sails like these, with tall yards, the top panel represents about half of the total luff length so if one puts just a bit camber in the top panel, very much can be won.

Cheers,

Arne

Getting tempted with "Ideas we would not agree with today" I had a very intreresting look into the thinking of the Honorable mr. Smith. Reading it with novel eyes, it seems to me that the old master stumbled over the culprit without recognizing the real deal: Camber in the sail. Being too concentrated on turbulent/ linear airflow, he seems to have introduced camber in the sail, (bending battens) and experienced a great improvement in performance. Being concentrated on turbulence, the camber factor seems to be forgotten. Please reread and comment. Personally I intend to add a sort of slot in front of the sail to see if I can move the pulling forces of the sail a bit more forward to increase the sails performance close to the wind.

Yours

Ketil Greve