MAX EBB — "W
MAX EBB
eight to leeward!" shouted the skipper. The race had started in a pleasantly warm northerly breeze, but as often happens with light northerlies in early spring, it had faded by the second windward leg. "More leeward weight!" he repeated. "I need more heel angle!" We all slid our feet over the leeward rail, leaning out against the bare lifeline wire. "Why are we doing this?" asked the novice crew sitting just astern of me. "Don't the sails and fins work better when they're vertical, so they can project more of their area to the flow?" Lee Helm had brought one of her engineering grad student friends along for the race. He was not a sailor, but knew enough about hydrodynamics to be dangerous. "We're using gravity to keep the sail full," I answered. "There's not enough wind pressure to keep the sails in the proper shape, so heeling the boat helps. What little wind there is will find something resembling the right shape in the sails." "That's true, but it's, like, mostly for helm balance," Lee corrected me from her perch forward on the rail. "Gotta heel enough to put some weather helm on the boat, 'cause the keel and rudder are more efficient if they both lift in the same direction. Induced drag is minimized if the spanwise lift loading is distributed
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Latitude 38
• April, 2018
evenly on each foil." "Good point," said the new sailor, who seemed to fully comprehend the point Lee was making. "If heel were zero," Lee continued, now directing her explanation at me, "the boat would not have any weather helm, the rudder might have to push to leeward
"I'm never happy unless I'm pointing higher than all the boats around me." to hold course, and the keel would have to do all the work resisting side force." "Isn't helm balance controlled more by mast rake?" I asked. "The range of adjustment for mast rake is, like, only 10 or 20 centimeters," said Lee. "But heel angle moves the rig side to side by meters. The books show helm balance as being all about side force, but there's a forward thrust force from the sails too. Heel moves the thrust from side to side, so heel angle has a big effect on steering force. Changing heel angle is, like, the quickest way to adjust helm balance." Meanwhile the wind had started to come back.
"Too much heel!" called the skipper. "Let's move a couple of bodies to windward!" This was a welcome development. I stayed on the leeward rail while Lee and her friend moved to the high side. I expected to join them on the windward rail as soon as the wind came up just a little more, but instead it held at around eight knots. A larger and faster boat was starting to gain on us from astern, threatening to roll over us to windward. "Let's move to centerline," Lee suggested quietly, gesturing that I should come off the rail while she moved down to the boat's centerline. "Get right under the boom," she instructed. "If we do this right we can seal the root loss from the mainsail, and point higher." The three of us, in our PFDs and foulies, filled up the air space nicely between the front half of the boom and cabin top. "That should give you, like, another degree of pointing," Lee called back to the afterguard. "Good, we're trying to pinch up to give that boat on our stern some bad air and hold them off," replied the tactician. "But, like, don't sit on their face," Lee advised. "That will make them tack, and we want to stay in safe leeward position where we're lifted a little in their upwash. We're going faster with them on our windward quarter than if they weren't there." It was subtle, but it seemed to work. With our bodies blocking the air flow under the boom, we were pointing high enough to hold even with the oncoming threat, and stay in the advantageous safe leeward position. "I'm never happy," announced the s k i p p e r, " u n less I'm pointing higher than all the boats around me!" "A pincher," Lee whispered. "But on this kind
