Barry & Meps / Stellrecht & Schulte wrote:

Rodney Whitworth wrote:

Hello,

You seem to be suggesting I put a split junk sail on my foremast and a non spilt one on my mizzen(aft) mast. As david Tyler has suggested  the problem is going to be the distance between the two masts forcing one into a high aspect ratio sail. It is becoming quite an interesting combination of compromises!

I'm suggesting that it is worth consideration, but I'm hedging my bets a little.

I do agree that two-masted boats like these pretty much force fairly high aspect ratio sails.

I cannot see a reason to put a split junk sail on any mast except the front one, so that part of the recommendation is firm too.

Until I do some sailing on my rig, I'll hold back from giving too strong a recommendation for the split rig in a two-masted boat. 

Barry

Now that David Tyler has listed some of the disadvantages of the split junk(flappy jiblets) I think I am going to go in Jonathan Snodgrass's direction for my first effort into JR and try to keep it simple. I will watch carefully for your postings after you have got to sea with your new canvas. Best of luck!

Rodney W

Barry & Meps / Stellrecht & Schulte wrote:Rodney,

Flutterby is a Freedom 33 (in the US aka 35 in the UK/Europe), and I expect to have the sails I designed for her up in a few weeks, and be able to report more about them.

I sewed cambered sails, but did make my main sail more like Slieve's split rig. I believe there are reasons to use one on my forward-most sail:

1. Slieve believes that having a "jib" like sail which has a clean leading edge out fully in front of the mast has aerodynamic benefits.
2. When making cambered sails, either sewn or hinged battens, there are practical disadvantages to putting more than ~5% balance forward of the mast. When I drew up a rig using my existing masts, more balance on the main (~15%) seemed like a good idea to make the overall sailplan balance the boat better. A split sail behaves well with at least this much balance.

The first point would apply to any multi-masted rig. The second is specific to the Freedom 33. The main/mizzen balance and underbody are different enough between the other Freedom cat ketches that I won't speak to them. 

Some Freedom 33's also have a "tall rig" with a bigger main mast than mine, and that would change things too....although several junk sailors feel that Freedom made cat ketch masts which are taller than is needed for a properly sized junk rig. I designed mine use pretty much the full hoist of the masts, giving me pretty generous sail area.

Look for much better answers as to how my ideas worked out after some test sailing.

Barry

Hello,

You seem to be suggesting I put a split junk sail on my foremast and a non spilt one on my mizzen(aft) mast. As david Tyler has suggested  the problem is going to be the distance between the two masts forcing one into a high aspect ratio sail. It is becoming quite an interesting combination of compromises!

David Tyler wrote:

Jonathan Snodgrass wrote:Could I please ask David:  After years with junk rigged boats your latest modification of Tystie was to a wing sail yawl.  However, it is not something that I have seen you recommend to anyone else.  In the case of Rodney, you perhaps haven't considered it as an option because he specifically asked for advice about junk rig sails.  However, he did include ocean robustness as one of his factors for consideration.  Would you care to comment?  jds

I do think that my wingsail ketch rig gives better performance, and more driving force for a heavy boat,  than I could have got with a more conventional junk rig in ketch format - the only two masted option open to me. I don't think that the performance is very much better than the big single sail, fanned and cambered, that I was using before. The chief reason for changing was that I didn't feel the big single sail was entirely suitable for ocean cruising, though it was enjoyable to use for coastal cruising.

Having said that, it is difficult to put a two-masted rig on to a boat of less than 30ft, and starting from scratch with a boat of 28ft, I would undoubtedly build a single sail similar to Fantail's.

  I hesitate to recommend the wingsail to others for several reasons:

1. It requires rather more engineering skill than does junk rig, to make up the wishbone battens. I would like to be able to assure myself by direct contact that anyone taking on the job has a suitable workshop and sufficient levels of skill. I used Paul Thompson's workshop to make my latest set of battens, and I had the opportunity to see Paul at work; I know that he can do the job, and can complete the wingsail rig for La Chica.

2. What I call the "80:20 rule" applies: it takes 20 units of effort to get 80% of the available performance; it takes another 80 units of effort to get the remaining 20% of available performance. Or call it cost/benefit analysis if you like. Either way, I feel that most people will get the most bangs for their buck by making one of the single-skinned junk rig variants. Leave the wingsails to we techies who just have to keep on designing and building things, because that's what keeps us amused and out of more serious mischief.

3. I'm still struggling with ensuring the longevity of some of the batten components. I can't yet give out a recipe for a wingsail such that I can guarantee long term reliability.

 I broke several components during the Tasman Sea crossing (they were some of the original plastic parts that had become UV-degraded), and any such breakages are harder to deal with, being inside the sail.

4. The sail is simple to make, but is 1 1/2 or 2 times the area of a single-skinned sail. More work, more weight, more expense.

I'm still happy to talk to anyone who wants to build a wingsail - but they've got to want to build a wingsail, for the engineering challenge of it. There are other, simpler, less expensive ways to get a good rig.