Re: Hobie 16
Posted: August 7th, 2016, 9:25 am
Kevin,
There are two kinds of reefing. There is reefing for survival and there is reefing for speed.
Reefing for survival is reefing from the top down and rolling the excess up at the foot. Now you have less sail area and a much lower aspect ratio sail. Sail aspect ratio is in the denominator of the sail induced drag calculation. Lower aspect ratio increases the induced drag coefficient. I wonder why sails are getting so tall and narrow now days? Look at the A Cat class. They could have any sail plan form they want and look what they have evolved to for highest performance.
Reefing or reducing sail area for speed is making the sail more narrow but keeping full luff length. Remember that the sail area that produces forward thrust is the front half. So don't reduce that area. The sail area that it pushing sideways and making the boat fly a hull and reaching max righting moment in less wind is the aft half of the mainsail. So reduce that area. Cut the leech back. I have reduced the sail area in my main and jib by 30% by making the sails more narrow. The boat is definitely faster in winds of 15 mph and more with the narrow sails than with the top down reefing. Another benefit of the narrow is that the sail becomes very "twisty". By that I mean the sail twists and untwists very quickly. Power up and power down happens with a small amount of mainsheet movement. The puffs are much more manageable than with the full size sail or with the top down reefing scheme.
There are two kinds of reefing. There is reefing for survival and there is reefing for speed.
Reefing for survival is reefing from the top down and rolling the excess up at the foot. Now you have less sail area and a much lower aspect ratio sail. Sail aspect ratio is in the denominator of the sail induced drag calculation. Lower aspect ratio increases the induced drag coefficient. I wonder why sails are getting so tall and narrow now days? Look at the A Cat class. They could have any sail plan form they want and look what they have evolved to for highest performance.
Reefing or reducing sail area for speed is making the sail more narrow but keeping full luff length. Remember that the sail area that produces forward thrust is the front half. So don't reduce that area. The sail area that it pushing sideways and making the boat fly a hull and reaching max righting moment in less wind is the aft half of the mainsail. So reduce that area. Cut the leech back. I have reduced the sail area in my main and jib by 30% by making the sails more narrow. The boat is definitely faster in winds of 15 mph and more with the narrow sails than with the top down reefing. Another benefit of the narrow is that the sail becomes very "twisty". By that I mean the sail twists and untwists very quickly. Power up and power down happens with a small amount of mainsheet movement. The puffs are much more manageable than with the full size sail or with the top down reefing scheme.