…but before the sea freezes, I might take off the jibs altogether and see what happens with a high-AR unbalanced mainsail only.

Hi Jami,

It's unlikely you suddenly turned into a bad sailor.

I think you've probably hit the nail on the head with option (a).  There just isnt enough space between the jiblets and the main for all the air coming off the jiblets to escape, without running into the luff of the main. The collapsing main is going to reduce the forward vector of power being produced as well.

While increasing the jib sheeting angle should in theory mean you can't point as high, perhaps the less restricted flow of air of a wider slot might improve the overall power being developed.

One disadvantage of the SJR is that we can't ease out the jib to open up the gap.  It does sound like there's a lot of air trying to squeeze through the gap.  As can be seen in your video, when the gust increases so does the backwinding of the main, which seems to indicate a lack of space for the air to escape.

I wonder if you are pointing as high as you really can despite what the telltales are saying?

Might you try, purely for experimentation, to luff up slowly until the jibs are just being backwinded and see if your tacking angle and VMG speed improves. See what the telltales are doing as well, at that time.

Also, close-hauled angle is not the only game in town.  Your Velocity Made Good upwind is also a consideration, I suppose.

I suppose, again for experimentation, before getting out the sewing machine again, you could try moving the main panel back from the Mast and/or the jiblets forward to see if a larger gap might do the trick before sewing yet more panels or lenses to increase the sheeting angle of the jibs.

Though of course moving the main back is likely to increase weather helm a bit again.

The above suggestions might be worth a look before dragging out the sewing machine again.

regards DaveD.

Arne:

Now, with the new powerful rudder in place, would it be possible to try your boat with the un-split sail once more?

Arne

I wish - but unfortunately (and then again fortunately) I sold the sail and it was shipped to Britain.

Jami,
About pointing angle; I wonder if you expect a little too much from the SJR? As far as I know, there has not been any other boat which has been converted from a fully cambered un-split JR to SJR, so it is hard to tell. However, after having met a few boats (with BR) the last seasons, and tested my Ingeborg and Frøken Sørensen against them while closehauled, I think one will have a hard time outpointing my boats. Of the three last boats I met on a beat (light to moderate winds); an Alo28, a grp Knarr and an Albin Express (!), two of them went as fast or faster than Ingeborg through water, but Ingeborg still outpointed them enough to keep up with them or beat them.
Therefore, if someone shows up in Stavanger with an IF, to race against us, he or she must have a seriously good rig to beat us.

I wonder if the main forte of the SJR (over the unsplit low-balance JR) is lighter sheet forces and easier steering on a reech?

Now, with the new powerful rudder in place, would it be possible to try your boat with the un-split sail once more?

Arne

Hi Jami,

I really really admire your workmanship and am sorry to hear you’ve been having problems with your rig.

I assume looking at your photos that your mast position remained unchanged from it’s Johanna sail position, and that this was why you constructed your SJR sail with less balance than recommended , ie shorter jiblets?

I’m wondering if this has meant that less power from your jiblets has shifted your centre of effort aft, thus resulting in the aggressive weather helm you have experienced? I am only speculating, hopefully someone with more knowledge than I will chime in.

On my SJR rig I haven’t encountered these problems.
BooTwo will point about 35 degrees off the apparent wind, and will happily exceed hull speed close hauled. Weather helm only becomes aggressive when I should have reefed earlier, and is a sign for me to drop a couple of panels.

I mention this not in any way to gloat, but just as a comparison to illustrate that whatever the cause of your issues, I’m confident in the effectiveness of Slieve’s design.
I am sure you’ll get to the bottom of it.

good luck!