Take a look at Harbor Wings website they have added a sections on Frequently Asked QUESTIONS

this should answer most of the questions we all have had on Wing Sails

http://www.harborwingtech.com/faq.htm

Here are there Questions

What is new here? Hasnít this been done before?
What happens when the boat is docked or moored in heavy wind?
How do you reef the WingSail?
What makes the WingSail turn?
What controls the WingSail angle of attack?
How do you trim the WingSail for varying top to bottom wind conditions?
There are no stays. How does the WingSail keep from breaking off in rough seas?
How well does the WingSail perform up and down wind?
How would you pilot a recreational catamaran with the WingSail system?
What happens if power or a computer fails?
Can WingSails be applied to Monohulls?
What other applications are there for the Harbor Wing system?