Do the masts turn? As this has been asked at the pond side many times, I've attempted to answer in drawing form, working on the premise that a drawing is equal to a thousand words.

The simple answer is "No". A servo is connected via the foremast to a yard on the main mast, this yard then turns the other yards. My own invention is the tensioning system (inset right). Rather than using springs or elastic, the sheets (ropes controling the yard) pass through pivoted metal arms which drop to take up the slack when required. This system is used on each of my square riggers.

Much more detail on the sail control mechanisms is given in Davids article in our "Hints and Tips" section on "Square-Rig Sail Control"