For everyone but the multihull competitors, the course areas were set east of Key Biscayne, just a couple miles offshore. For the duration of the event, the southerly breeze was slightly more to the west than the 'normal' southeasterlies, making for an interesting scenario in wind and wave sailing. Though the wind showed a tendency to bend around the southern end of Key Biscayne, the wave pattern was more uniformly from the southeast, and often at a significantly different angle than the wind. This made for a completely different kind of sailing on each tack upwind. On starboard, boats were taking the waves and chop head-on, while on port, the waves were hitting the boats on the beam for a slightly smoother ride. To optimize speed, balance, and pointing ability, this meant adjusting the sail trim in a different fashion on each tack—twisted but powerful on starboard, and a little flatter and less twisted on port.
For those of us sailing on the offshore one-design course (including Mumm 30s, 1D35s, and Farr 40s), the first challenge in these circumstances was to decide first how to set up the rig. Without the dynamic rig adjustment of running backstays or checkstays, the middle shape of the mainsail is controlled by mast bend, which in turn is controlled by adjustment on the diagonal shrouds. Since these could not be adjusted except between races, the question became whether to try and optimize the tuning for the deeper and more powerful shapes necessary on starboard tack, or the flatter shapes that were better for port.
On John Musa's 1D35 Jacaibon, we opted for having a little more bend and flatter shapes appropriate for port tack, reasoning that if necessary we could manipulate other controls such as the outhaul to deepen the main on starboard. Also, as the day wore on we saw a tendency for the wind to increase, and we wanted to make sure we would therefore be fast on the last beat of the race as well as the first.
The most dynamically adjusted aspect of sail shaping that we tried to manipulate was the twist in the leech. On starboard tack, the impact of taking the waves head-on made the boat pitch more readily than on port tack. This meant the angle of attack of the wind on the sails would vary widely, especially at the top of the spar. So, in order to reduce the risk of having the sails over-trimmed and therefore stalling the flow of air, we would put more twist in the main and maybe a little more as well on the jib. This meant easing the jibsheet about an inch or two from where it was on port tack, and a similar and sometimes greater amount of ease on the mainsheet. While a little pointing was sacrificed, the twisted shape made the boat perform consistently faster through the waves, with the balance on the helm and heel angle controlled through adjusting the traveler.
After all this work getting upwind, going downwind was a blast, especially on port gybe where at relatively close true-wind angles we were all easily surfing down the waves. Fortunately both the finishes and the harbor were downwind, so it made for great endings to some long days!
If you encounter similar conditions when you race, keep in mind this simple lesson from the 2001 Acura SORC—when sailing upwind, the bigger the waves (and the more head-on they are), the more the twist.
Shifting Gears Upwind by Rich Bowen
Basic Roll Tacking by PJ Schaffer
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