Gentlemen,

   Thanks so much  for your input.   I'll  do as Arne suggests  and move the discussion  to a new thread (Catamaran  bridge deck mast question).

Thanks!  Brian 

Brian, two points about stayed junk rigs:

1) Obviously, you can't let the sail out so far on a run, so you are giving away one of the advantages of junk rig. Since this is a relatively fast cat, you may have the apparent wind further forward for more of the time than with a monohull, so you might be able to live with this. You would have to take more care with anti-chafe patches on the sail than we normally do, but again, it's doable.

2) When you're at that stage when the sail is fully hoisted, but the YHP hasn't been taken in and belayed, the heel of the yard is going to be further forward, and may snag the forestay. With care, this needn't be an insuperable problem. A higher yard angle may help. Arne's sailplan has a yard angle that is a reasonable maximum for an unstayed rig, but I've used a greater angle, at the expense of greater loads on the YHP and LHP. 

[you need to take the links for your photos from your directory profile, not from the albums where you upload photos - only you can see those. Look for "My directory profile" at the top of your profile page]

Arne Kverneland wrote:

Brian,

I cannot tell on a general basis if a junk rig, stayed or un-stayed, will work on a catamaran.

I suggest you show us the cat you have in mind, and then see what ideas that members come up with.

Arne

Arne,  

Sorry, I  needed help uploading photos.  Hope this works.   The boat is a Latitude 8 built in Phuket.  Appreciate your thoughts.   Brian

Brian,

I cannot tell on a general basis if a junk rig, stayed or un-stayed, will work on a catamaran.

I suggest you show us the cat you have in mind, and then see what ideas that members come up with.

Arne

Hello

My Tiki 46 Grand PHA has a bi-plan rig with one free wooden mast on each hull.

The rig with Swing wing sails has been designed by Alan Boswell via Sunbird Marine and I don't regret to have increased the diameter of the mast because our friends who owned the Tiki 46 Apataki bought a complete rig ready to use prepared by Sunbird Marine and they had a lot of problems due to mainly a mast not enough strong and so with the battens articulations.

Each sail is 55m² and even with gusts at 35 kts with all the sails the masts are always OK with only a light bending on the top. The initial Wharram sailing area (a shooner Tiki rig) with a jib has a total of 91m².

When closing the wind with a such double sails it's easy to see that only the first 1/3 front part of the sail works with the leeward of each double sail receiving a good  pressure due to a good low pressure in this area. In fact the total sail area works only with the apparent wind coming from abeam until down wind.

In using articulated wishbones as on my previous Tiki 30 PHA the sails were more powerful and if I use now on my Tiki 46 long wishbones with no articulations it's only to have a stronger rig able to to sail offshore in bad weather with a minimum of worries.

The big problem when sailing offshore is, due to the crossed swells, the movements between the masts and the battens and each day I check if all is OK to don't damage the masts.

When the sails will be too much tired, I don't want to have again  double sails because the sail cloth is lighter and so more fragile and impossible to repair with a sewing machine. Each sail has a  total of 110m².

The bi-plan rig is very easy to handle. Very often when the wind is above 25kts I use only the windward sail. So the sail is well centre in the middle of the cat.

The only problem is at down wind twice I damaged the sails due to uncontrolled jibes. In this case the ends of the wishbones can touch the opposite sail and to damage them.

In New Caledonia in sailing in the lagoon along the coast I had more attention to avoid the reefs than to look at the wind direction. Suddenly, perhaps due to the modification of the wind with the mountains, the wishbones of one sail damaged the other sail.

Before the night we were able to repair the sails with strips of new sail cloth glued with a neoprene glue. In fact it's stronger than in stitching because the efforts is spread on a larger area. Since after thousands more miles the repairs are always OK.

Now Grand PHA has a long rest on the ground in Whagarei (North New Zealand) . Due to family problems I fly back in France until the end of this year.

I begin to search for more efficient, lighter, stronger and more simple sails to replace in one year or two my present swing wing sails in using my good free masts. Wing sail Tiki sails or the hybrid junk-gaff rig of Phil Bolger?......

You can find more details on my Wharrambuilders page in English . Sorry but the blog "Sailing with Grand PHA" is stop in Panama!! I have to actualised it.

I regret the Junkrig association web site has not so many possibilities to share ideas and experiments than http://wharrambuilders.ning.com/  .

Since Panama we changed our tracking system and we use this one integrated a blog.

Bertrand