Structured luff jib on a structural furler

Am planning a structural furler for a Corsair 31 trimaran. Swivel at the top, furler at the bottom, connected by a armare PBO torsion cable which serves as forestay, and transmits rotational force.

There wil be no way to adjust luff tension on the go with the halyard. (considered and rejected Colligo ELHF and Ubi Maior Jiber for various reasons). Head will be either lashed at the head, connected to swivel with a lock, or raised by an integral halyard tht lives in the zipper luff.

In any of these cases, there will be a lashing or tackle at the tack to tension the luff. But adjusting this tensioner as the wind rises will be difficult or impossible. Really this is a set and forget setup, and there wil inevitably be some loss of performance.


Ian wondering if I can minimize the need for adjustment by going to a “structured luff” jib, as developed by Doyle and north. This is a jib that has enough continuous fiber in the luff to share a significant part of the forestay load. Say 50 percent.

My thought is that if there is no halyard to stretch (because the head is lashed to the swivel) and the sail itself doesn’t stretch any more than the forestay, you really can’t lose luff tension relative to the forestay- and therefor would not have adjust luff tension as the wind rises and falls.

is this right?

bonus question: does anybody know what Doyle’s new “hybrid” sailcloth is? They been teasing it for a month now. Looks like some kind of spread filament deal to me, like DP’s Tyra Flex or north’s 3Di.

 

Adjusting tension with lashing or tackle is not hard. However, if you want the luff to take the tension, instead of the forestay, the lashing or tackle has to be sized appropriately since a failure will demast the boat. Also, if you have to take down the sail and then operate the boat, it may demast because it needs the sail to assist the forestay. There are lots of systems that work well. This is re-inventing the wheel and making it square instead of round.

 

In my case, the forestay/torsion cable will be sized to take the entire load.

Standard furling systems (I.e. with a luff foil) don’t work as well on this boat because the boat already has a pitching problem, which is exacerbated em by the weight of the a steel forestay and aluminum foil. And there are a number of of other reasons that the standard approach is less than ideal for my boat.

Hence the desire to do a structural furler.

 

What is the weight of your proposed system compared to an aluminum foil?