In medium winds the conditions on the water can range from flat water to large swells. The top sailors are able to maintain their vmg while constantly observing the conditions on the course to make strategic tactical decisions. In flat water the speed differences are relatively small and the boat requires little steering and body movement. In waves, technique plays a role because sailing fast requires a great deal of body movement.
In medium air the goal is to set the rig for maximum power until the boat is overpowered. The most powerful sail shape in these conditions comes from sheeting in block to block with the mainsheet which, creates maximum leech tension. It is important to have a tight traveler so that the boom does not slip towards the centerline altering the sheeting angle and causing a hooked leech. The draft should be 45 percent at a depth of about a hands length at the boom cleat or 4-6 inches. As the boat becomes overpowered the vang should be used to reduce the leech tension and bend the mast. The vang is litterally like the gas pedal in the laser. As the wind increases toward the higher end of the range the cunningham should be used to pull the draft foward in the sail. Weather helm is a sign that you need more cunningham and/or to hike harder and flatten the boat.
The boat should be sailed flat in medium air and the sailor’s front leg should be next to the mainsheet cleat. As the waves increase the boat should be sailed with a consitent heel so that the waves are washed off to leeward instead of filling the cockpit with water. Bear away when sailing through choppy waves to accelerate and push through the waves. Steering and body movements should be linked together. Rudder movements create drag so the more the sailor can steer with body weight the better. As a wave approaches, lean back and head up to lift the bow and accelerate the boat forward. As the bow crests the wave lean upright or slightly forward and bear away for power down the back of the wave. The speed of the movements depends on the waves. Small waves require sharp movements where large waves require smoother and slower movements.