Ah! Michael ! You don't get it, do you!
I'm not interested in all this "my rig is better than your rig" acrimony. (Although I am against Bermudian Fascism in all its forms and admire your junk rig enormously.)
Sure, an expensive, highly stressed Bermudian rig will go better to windward than a balanced lug , and so, too, will a well designed, cleverly cut, fiendishly strung, fully battened lug, I'm sure, although, if you come up against a speed machine like the Goat Island Skiff (rigged with a balanced lug ) you might find it going to windward quite as well as you do. The point is that the balanced lug is used on my cruising boats for its simplicity and handiness - unstayed mast, halyard, downhaul and mainsheet - that's it! The sail is rigged quickly, raised without winches, more importantly for a single hander, drops instantly and securely and looks after itself. No slides to stick, no rigging to tangle, no fuss, no bother!
In performance, any type of lugsail (or sprit sail - see Thames barge,etc..) is superior, m² for m², to Bermudian on any point of sail - other than to windward. It gybes sedately in a blow, without taking your head off or breaking any gear, heaves to easily, won't deafen you with flapping canvas if you lie head to wind, and, unlike a spritsail, reefs easily. (All the points that you highlight for your junk rig - but simpler. )
The Bermudian compromises all of that for much better windward performance. Worth it for a racing machine when you can fly a spinicker to overcome downwind deficiancies, but for my kind of sailing, rather throws the baby out with the bath water. Having said that, I see no harm in getting as much windward performance out of MY lugsails as possible - hence my interest in John Leather's writing - rather than his books, which seem to have become collectors items, rather than valued for their content. (A shame, but never fear. Someone will digitise it on "Kindle" for free sooner or later.)
Aerodynamically, an aeroplane's wing is pretty well understood, a Bermudian sail seems to behave in a similar manner but square sails? There's something weird going on when a slight adjustment of the halyard position on the yard or downhaul position on the boom can make a huge difference for good or ill - and will also be affected by factors like wind speed and the sails' angle of attack. (Is this why controllable fully battened junk sails go so well?) Are you familiar with the Catastrophe Effect, where one state suddenly flips over into another? I get the impression that something like that happens with the non-laminar airflow over square sails, especially off the wind. "Flip"and you're going like a train; "flip" and your dead in the water!
I would simply like to know more!
