I was strongly reminded of this rule of thumb while sailing off the south coast of England during most of August. We had 1,000 miles of sailing in the 50-foot Bob Derecktor-built ketch Snow Lion. Most of it was racing: a 110-mile overnight race in the English Channel, the 605-mile Fastnet Race out to Ireland and back, and a total of eight long day races in Cowes Week (that annual gathering of 1,000-plus racing boats), and the extraordinary America’s Cup Jubilee. The last, a floating history of great yachts and great sailors, was the most splendid regatta in history—a vivid reminder of our pastime’s historic roots in technological progress, aesthetic beauty, and sportsmanship.
Throughout that exciting month of racing there was plenty of time and opportunity to study the behavior and consequences of current because there was so much of it. Accurately judging laylines when we tacked and jibed for marks was a constant problem. After a while we became adept at finding ranges (the Brits call them "transits") against which to gauge whether we were holding our own against a side current.
With a range of between two and four knots, the differences were dramatic. A reliable rule of thumb is that a one-knot current running into the wind doubles the size of waves. Stronger currents have an even more radical effect of making waves higher, steeper, more frequent (with a shorter period), and more unstable, with white water flying everywhere. All this of course affects every aspect of sailing, from sail trim to steering to tactics. Normally the rule of thumb when beating is "sail in smooth water" because, then, a head sea slows a boat. But if a favorable current is running, lumpy seas can be good for you, if a little uncomfortable.
It’s not generally known that current also affects wind speed, sometimes profoundly. A boat sailing closehauled in a favorable current always has a surprising amount of apparent wind. To determine apparent wind speed, add the true wind to the boat’s speed (or, when beating upwind, to about 0.75 the boat’s speed). After the Fastnet start, on the sprint out of the Solent the four-knot favorable tide and our eight-knot boat speed gave us a speed over the ground (SOG) of 12 knots. This transformed the Force 6 (22-27 knot) true wind into apparent wind readings sometimes in the gale range of Force 8 (34-plus knots). Had the current been ahead, our SOG would have been four knots and the apparent wind in the mid-20s. In this blow, some crews severely shortened sail in order to be under better control so they could stay clear of competitors. A few sloops were under jib alone, one boat set her storm trysail in place of her mainsail, and we on Snow Lion eventually doused our main and sailed under headsail and mizzen (the famous combination known as "jib and jigger."
In the Fastnet, because the Royal Ocean Racing Club started smaller boats early and larger ones later, the crowding was dense as the large fleet squeezed into the narrows off Hurst and the Needles (the chalk towers at the Isle of Wight’s western end). Some people enjoyed this, but most of them were ashore. Yacht racing in England is a spectator sport, and several people who watched from Hurst later told me they had never seen anything like this big fleet pounding its way upwind, bow-to-stern, on the evening of August 12. On the water, the crowding was at times conducive to serious frights. As far as I know there were no collisions, and for that we can thank the fleet’s seamanship skills.
When the wind, sea, and traffic eased, we got our main back up and beat for 30 hours down to Land’s End. After the turn, there followed 15 hours of thrilling reaching toward Ireland until a front came through and left us with some more beating. The conditions were astonishing when we tacked around Fastnet Rock at sunset on the third day, with a rainbow to one side and the lighthouse backlit by the post-frontal clear, orange sky. A fast run got us to the finish at Plymouth 35 hours later, the 24th boat to finish, but with that exciting hard beat in a strong current still fresh in the memory after three and a half days, and with the knowledge that the English Channel and the Solent still had a lot of tidal current left to heave at us.
Defending the JubileeI must take issue with my editor and friend Dan Dickison’s concerns about the long-term value of the America’s Cup Jubilee (see Jaded on the Jubilee). Not only was it the most fabulous gathering of sailboats of all kinds in history, but it offered great hope for the pastime’s continuing success. Anyone who has doubts about the value and symbolism of the Jubilee should consider three facts:
First, it was an example of admirable sportsmanship. The Royal Yacht Squadron was sponsoring the nautical extravaganza in honor of the 150th anniversary of its losing the America's Cup.
Second, the Jubilee helped heal old wounds. At the end of the week, the flag officers of the co-sponsoring New York Yacht Club awarded the prize for "The yacht that has brought the greatest benefit to the sport through participation in the America's Cup Jubilee Regatta" to Australia II, the boat that under a cloud of controversy and bitter feelings in 1983 took the Cup away from New York after 132 years. All (or most) is forgiven.
And third, while celebrating the past, the Jubilee celebrated the future. The RYS and NYYC acknowledged the pastime’s continuing vitality when they named as overall regatta winner Bear of Britain, a Farr 52 sailed by a crew of 17-25 year olds and skippered by a former National Optimist Champion. Yachting lives!
Basic Thoughts on Tide by Jim Sexton
Using Tidal Current Tables by Jim Sexton
Understanding Tidal Currents by Jim Sexton
Buying Guide: Chartplotters
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