Keeping the boat flat and controlled…
Initially while (Daniel) the leeward sailor was hiking and working he was the faster boat, the windward sailor (Ogawa) was moving his tiller and allowing the boat to heal. As the windward sailor relaxed he started making better use of his main-sheet and less use of his rudder combined with Daniels lack of hiking Ogawa was a lot faster. There are 2 important things here:
(1) Sail shape – notice the centre of effort in both sails is very low and the leech is open in order to depower the boat and balance pressure on the tiller. By using the main-sheet as pressure on the sail changes in order to keep the boat flat, the sailors keep the boat sailing in a straight line.
(2) Fitness – even though Daniel is taller and heavier then Ogawa he was unable to keep hiking flat out for a long enough duration, Ogawa was hiking harder and was constantly faster all through our training mainly for that reason. As both their techniques improved the fitness factor became more significant.
At Toplevel Sailing we put a big emphasis on those aspects during our sail coaching. Understanding the sail and knowing how to depower the sail for maximum control, minimizing rudder movements to ensure speed and off course improving the dedicated sailing fitness of our sailors.