Keith,

hope you go for it, too few Junk multi's out there.

Definitely a Cat - I would only look at a Tri if looking for something smaller.  Even my wee 23' Hirondelle  (now sold) had standing head room (for small people) in the hulls, plus 5 berths and decent size heads -  You get a lot for your money! 

 What are you looking for accommodation wise?  I have looked at one or two 25-30' Cats for JR conversion.   The older heavily built bridge-deck Cats should be able to take a single mast not too much engineering, especially if a more balance rig  - i.e. Split rig.  If you keep your eyes on what is for sale there are many bargains (not as many as monos) I reckon £20-£30k will give you a very good Cat, converted, if you are prepared to do a bit of work

Pete Hill Oryx and earlier China Moon, as are Bertrands Pha /Grand Pha are excellent examples of ocean-going Junk Cats.  All new and owner built, which is a lot more work and dedication.

Best of luck.

I have no experience with trimarans, myself, but Bunny Smith's experiments on his tri seemed pretty successful.  he wrote about them in the magazine, but I'm afraid I don't have time to go through the index and find it at present.  However, you can find the index and download the magazines here.

Hello all,

I am glad to see that I am not alone in my interest in a Junk-rigged multihull. I spent some time looking into this last year, and ran into some significant roadblocks.

My original thinking was to marry the junk rig (for its cruiser friendliness) to a multihull of about 11m, (for its comfort) to create a nice, low-stress offshore cruising platform. I quickly found out that this was not an endorsed combination. For trimarans, the structural changes to accommodate an aluminum flagpole forward of the designed mast position were daunting. A designer of a popular model I spoke with did not want to entertain the idea at all. Similarly, for a catamaran, the bi-plane arrangement also encountered staunch resistance from its designer as well. That project looked to be more straightforward, but inevitably it involves a mast/flagpole puncturing the location of a bunk or the head in the current plans.

The additional frustrating thing I ran into was, inevitably, people assumed the JR idea was a cost-savings maneuver, and recommended I pick up a used Bermuda set up, and stick with that. Of course, by the time one added up all the necessary replacement bits and pieces and extra sails needed make to make a Bermuda rig safe offshore, it was never actually cheap.

So I am at a bit of an impasse. I think trimarans are a better design until you get above 12.5m length, because only at that point can you naturally accommodate standing headroom in the catamaran hulls without incurring too much windage. Plus a trimaran main hull (especially with solid decks and thus outboard bunks) works better as a unified space. Many of the good points about monohull interior design still apply, so you can take advantage of all that has been developed for them.

I am aware of the substantial cost differential between a good used monohull and trimaran; there are some great deals out there on solid older multihulls. But, personally, I hate leaning over when the wind kicks up. It just seems like one of those things we should engineer out of the sailing experience, to increase comfort. We already look to warm clothes to help us deal with cold weather, and cockpit enclosures to shield us from annoying wind blowing square in our faces, so for comfort (and safety) let's do something about all that leaning too. So it is a multihull for me. With a JR, if I can swing it.

Ed, you will need to think about how you are going to support the unstayed mast in the center of the boat. This is the beauty of a mast in each hull, there is sufficient bury for the free standing masts to be well supported, but on a small cat such as you are thinking of building stepping the masts through the hulls could have a negative impact on use of the interior space. For a free standing mast in the center of the boat you will need a substantial supporting structure built above the main beam. Because of the wider beam of a catamaran it might be possible to stay the mast but that could compromise the use of the junk sail.

Lots of fun stuff to think about!

I find "excessive turbulence" rather meaningless. Junk-rigged cruising multihulls sail under the same kind of aerodynamic conditions as do monohulls. True, a slim, light racing multi will have its apparent wind always well ahead, and this will not play to the strength of junk rig, which is at its best with freed sheets.

It's easy with a cat. Just design two equal junk rigs, of whatever type takes your fancy, and pop one in each hull. I think I remember that James Wharram has taken the view that rigs for his boats should be low, as they are in general rather narrower than some others. If that's the case, low aspect fanned sails would be one option.