Good to see all the interest and comments about my new catamaran, and I have had some direct contact about this as well, thank you all. We can always be sure of some good robust discussion and comment on the JRA forum.
I thought I should explain a little more the difficulties, or stumbling blocks, to fitting a junk rig. If I were to fit a junk rig to the boat it should be an improvement on the designed rig, be safe, be practical, and enhance the boat in looks, performance, and ease of handling.
Leeway Resistance The mast is placed in its current position above a reinforced bulkhead which also helps to divide up the accommodation space. The current, (single) dagger-board will be placed in its current position for reason of CLR, and the CE of the rig. I suspect the real reason it is raked forward as it is will be to allow the dagger-board case to exit through the sloping aft cabin bulkhead which allows for raising and lowering of the board from the cockpit. It is also possible to fit asymmetric lee-boards to the boat, these are mounted on the inside of the hulls under the bridge deck. Theoretically these could easily be moved forward to move the CLR forward. But there are some down sides to these lee-boards which include a lot of structure to support them which means more weight. There will be a lifting and lowering mechanism of some sort, and when sailing only one board should be down at a time. So, not as simple as the dagger-board.
It would also be possible to fit mini keels as is done on many cruising catamarans, and I have thought about this quite a lot because this would also allow for moving the CLR forward. But disadvantages are increased draft, extra weight, and mini keels on a catamaran can induce, or amplify the pitching motion which multihulls can be prone to because of all the extra buoyancy the mini keels introduce in the middle of the boat. Mini keels also reduce windward performance, and rob boat speed compared to a boat fitted with a good dagger-board, So once again the dagger-board is a better solution.
Mast Position When first thinking about a junk rig placing the mast further forward adjacent to bulkhead 2 seemed to obvious thing to do. But then when I studied the plans a lot more, and now I can see the hull shapes in 3D I realise that there is not a lot of load carrying ability in the forward sections of the hulls, they are very fine, which is no bad thing for this design. But that means that the load carrying portion of the hulls is from midships aft, which will also be a reason why the current rig is placed where it is. So placing a junk rig forward on the boat will put a lot of weight where it should not be.
Junk Rig Options I have had a couple of good suggestions regarding use of a split rig which which could solve the CE problem. But with one of these rigs, or a single junk sail of 20 square meters we end up with a lot of sail area up high, because of the quadrilateral sail shape. I am not so sure that a lot of sail area up high is that healthy on a potentially quite tippy coastal catamaran. Paul MaKay's Aero Junk rig would just about fit as a single mast rig, and I have not discounted this. But the wishbone battens add quite a level of complexity, and would this be more simple and easy to handle than the designed rig? I am thinking about an Aero Junk bi-plane rig with a mast in each hull in about the same fore and aft position of the current rig, or may be a little further forward. This could be made to work with each sail about 10 square meters. This would potentially allow the CE of the rig to be far enough forward and the masts may not interfere too much with the accommodation. I would also want the rig to look good. So I am playing with this idea a little bit.
Anyway the above has been my thought process. It is all a lot of fun and it is great to have such a project to get involved in and work ideas around.