Thank you. That makes sense. I also hadn't fully appreciated the relationship between the yard haul and sheets tensions. My model is looking a lot better :)

Hi

I have recently joined the association and have spent a happy few weeks going through all the information that is on the site. It is a brilliant collection.

 I am intending to fit a Split Junk rig to my John Welford designed Pathfinder day boat. This is currently setup with a gaff yawl rig and I will replace the jib and gaff with a Split Junk rig and keep the Mizzen. I am hoping to improve the speed in light airs because I have designed a bigger sail. Take advantage of the easy Junk reefing because the current set-up is quite difficult to reef and then keep the boat moving. Fix a bit of lee-helm and make the mast raising and rigging process easier and quicker, as I want to try some more adventurous dinghy crusing in different location. The boat is currently kept on Ullswater in the UK.

From all the information on the site, Arnie's articles, Sieve's Split Junk rig description (thank you for putting these on the site they have helped me a lot) and a read through of PJR I have a basic layout, mast position etc sorted (I Think!:). For the Split rig I am aiming for 6 panels(possibly 7), total of approx 12m2 area and the top two panels transitioning from a 5degree rise to a 35degree yard angel. The boat has 230Kg displacement, 1.95M beam and 5.25M overall length.

I am now doing the sketch design for the Split Junk rig sail which is nearly finished except for deciding on the Convex Luff.

In Sieve's article it is stated that the Convex luff on the top three panels is important but I I am not sure why this is important and how to decided how convex the luff should be? Has anyone any suggestions on how I should decide on the shape of the luff for the top three panels on a Split Junk rig?

Thanks in advance

Rob Wilkinson

First of all a big thanks to Edward for a great day last Friday aboard Amiina, in SE winds of 5 - 30 kn off Poole.

Having not been aboard a Junk rigged vessel for 30 years (Coromandel in the early 80's) i can say ' what a fantastic change has occurred'. Dealing firstly with the above thread, ie the use of battens to prevent flogging jiblets.

1) whilst reefed and stowed in the bundle

2) When still drawing in strong winds, and subjected to lots of twist.

Edward has fitted upper and lower sheets capable of being trimmed independently.

David Tyler's concern (above) that  due to wind shear and sail twist a situation could arise where with lower panels correctly trimmed,  the upper panels could be spilling wind and flogging - didn't arise. Being able to trim both sheets meant that all panels and jiblets were fully employed and drawing properly.

Two Sheets  were part of the reason, but we also had jiblet battens. Edward rig is 'work in progress' and he has fitted a variety of battens; full length, shorter and none.

We both felt that the full length batten, positioned mid-way in one of the jiblets looked to be doing the best job but was a little too thick at its forward end, we would both like to have seen the camber form nearer the luff. The other panels sporting shorter battens were able to form 'early' camber, but they didn't make such a smooth looking flow as the full length one did.

I deliberately luffed up in a gust to see the effect ( I also did it inadvertently being a poor and easily distracted helm!) but the leeches caused me no concern - even the panel without a batten. No doubt in stronger winds they could , but as the upper panels can be made bomb proof -  without splits and reduced camber for those conditions.

In the recent newsletter 65, on page 20 in the interesting article by Dave Zeiger he says

But without them, the jiblets - like any other
unsupported bunt of sail - will flop and flog
when lowered. Not a comforting prospect
for a cruiser in chronically windy country.

Exactly my concern also and one of the reasons for hitching a ride aboard Amiina.

Edward has designed a sail catcher which comprises alloy tube bent in a fairly tight U, the straight sections are about 6-7 " apart and are supported below the boom.The alloy arms form the mouth of a full length sail bag, into which the reefed battens and bunt are contained out of the breeze. They were totally quiet and protected. I didn't consider how they would drain out a sea but i think part of the bag was open netting - I'm sure Edward will describe this much better then me. My concerns of reefed jiblets getting into mischief were totally allayed.

Secondly, and taking liberties a little with the thread my other discoveries aboard Amiina were 

• How readily she tacked even when i tried at about 1 knot.
• How quiet it all was, no battens and mast rattling - Slieve's downhauls work a treat and the components are held quietly together when luffed and spilling wind.
• I tried a 'crash stop' involving : helm down - keeping it there, sheet in tight, keep it in.  She luffed tacked then gybed twice without drama , then settled down just off the wind - totally stalled. Wonderful.
• Reefing and making sail - what a doddle.  As we sailed back into Poole Harbour right into the marina berth it was gusty - but we were able to vary the sail area as easily as my car's throttle - certainly much easier than reaching over the stern to fiddle with an outboard whilst not looking where we were going.
• I know that i am preaching to the converted - and all these points are true of all JR not just SJ, but for me after 30 years of driving BR it was a real pleasure.
• I kept ducking instinctively to look under the genoa...I am a slow learner.
• I felt slightly vulnerable on the side decks without a shroud to lean on, so I hooked on to do the vital foredeck work, which was - photography.

Hello Edward,

I've got a few adjustments to Flutterby's sails and rigging in my next bit of work, but I'll just throw in my $.02 on this issue:

Fluttering of the jiblets is not one of the problems I've had much. I've sailed with full sails and reefed. I also spent a few days in the marina while working on her with the sails weathervaning in light to moderate winds, and don't remember flogging then either. I expect they would flog if weathervaning in heavy winds.

Flutterby also has very small jiblets compared to Slieve's recommendations; I suspect this further reduces the "problem" for me.