| 2002 Bermuda Race - Wind, Current and Results |
| TO SEE DAILY ROUTING/TACTICAL ANALYSIS OF PACIFIC CUP - CLICK HERE |
| The 2002 Edition of the
Newport to Bermuda Race presented a great opportunity for record times - and a major
challenge to competitors. Normally, racers cross the Gulf Stream at right angles, and
spend perhaps a few hours in the central flow. This year, a huge "meander" in
the normally eastward-flowing Stream turned it first south, for more than 150 nm, then
sharply east for just a bit, and then back north again before resuming eastward flow. The
southerly portion offered a 4-5 knot boost in the right direction, but was almost directly
opposed to strong southwest winds. When a boat is going with the Stream, but against the
wind, big waves pile up and the boats take a pounding. This is fairly common in races up
from Miami along the coast, but extremely rare, if not unheard of, in the Bermuda Race.
This made for very rough, if fast, sailing and, with strong winds almost all the way,
record times. From a routing standpoint, the Race presented two major issues: (1) how to handle the low pressure zone moving from the Chesapeake eastward across the rhumbline; and (2) how to take maximum advantage of the Gulf Stream (both the meander and a large warm eddy just north of it), while dodging cold eddies to the south. One needed to route well west of the rhumbline to work the current, but too far west could get one into the very light air associated with the center of the low. The trick was to stay east enough to avoid all but a touch of the low, but end up west enough to head south at the northeast edge of the warm eddy. This is tricky, but just the kind of situation that modern routing software excels at. Navigating on Morning Glory, I found that the Local Knowledge "Force 4" routing program did it just right, accurately predicting just when we would reach each point and picking the fastest route to sail the whole race. To be effective, of course, the routing software needs a good mathematical description of the wind and the currents. In this Race, we and numerous other boats used our Local Knowledge Gulf Stream predictive model, developed in collaboration with oceanologist Jenifer Clark and called "astonishing accurate" by top navigator Stan Honey on Pyewacket. For the wind, we took a free grib file off the navcenter.com site, and found this quite accurate as well. Applying appropriate polars for the boat, "Force 4" turned out the routing solution in seconds. BELOW WE RECOUNT THE KEY MOMENTS AND ISSUES IN THE RACE ... |
| Predicted wind at start (1430 EDT on 6/14), originally from due east and ranging to 25 knots (magenta vectors). Of main concern was the low pressure region approaching from the west; see light wind area to the left of the rhumbline to Bermuda (red line), at bottom left of graphic. The intersection of the low with the course meant a rapid shift from easterly to southwesterly winds, and a period of uncertain, light and shifting winds during the transition. This favored the larger boats, which were able to get by with minimal effect before the center went by. |
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| Predicted wind at 2400 on 6/14, with center of low at 39 deg latitude, east of the south Jersey coast. The colored lines show the routing solutions computed by Local Knowledge "Force 4" software, using the Local Knowledge current-prediction model for the Gulf Stream, a 5-day wind "grib" file off the web, and polars for Morning Glory, an 80-ft maxi. The red line shows the optimal route, and the black dot on each line the predicted position of the boat on that route. Predicted and actual positions were very close during the race and, as shown in the graphic, we got by and saw only the approaching edge of the low. |
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| Predicted wind and positions at 0400 on 6/15. The low, with approaching center of very light wind, has now moved further east, into the region (red line) previously traversed by Morning Glory and the other IMS 9 boats. This became more and more of a problem for the slower boats as they reached the low, with some of them spending 4-5 hours without wind. |
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| Predicted and actual positions of IMS 9 fleet at first morning report: 0800 on 6/15. The fleet has taken advantage of the east side of the clockwise-circulating warm eddy, and is about to move south to pick up the SE to southerly flow of a very extensive 150 nm "meander" of the Gulf Stream, with speeds up to 5 knots. This provided a huge boost for the boats that caught it right. We on Morning Glory (MG) are slightly east of the optimal route, having opted to play it safe earlier by sailing east a bit to avoid more of the low, then tacking back west to resume our southerly course. While tied for first in distance with Boomerang (BO), we are not quite as far along as we should be, and BO is better positioned to enter the main Stream first (which she did by 10 minutes or so). The next nearest boat, Pyewacket (PY) is some 8 nm back, and appears to face some adverse current at the lower edge of the eddy. Others, such as Carrera (CA), appear to have missed the southerly flow of the eddy, taking it more in the middle. All of these are small effects, however, compared to erring too far to the east (say along the rhumbline) and facing the adverse 4-5 knots of the northward-returning loop of the Stream (note the "blue" course avoids the worst of this and stills is almost 6 hours slower). [The left-hand column of the 'Best Course Comparisons' box shows time to the destination mark (here northern approach to Bermuda) in hh:mm] |
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| Predicted positions at 2000 on 6/15, emerging from the Gulf Stream. At this point Morning Glory was very close to her predicted position (black dot on red route), and the optimal route from there was pretty much a reach, in strong southwesterly winds, all the way to Bermuda, with perhaps a slight diversion to catch the west (southerly-flowing) side of a cold eddy at about 34.25 deg lat. Tactically, the race seemed to be over, and with a slight edge in boat speed MG seemed in great position to make it to Bermuda first. This was not to be. At that moment the mainsail halyard broke and it was too close to dark to rig another. While the crew rigged a trysail, Pyewacket caught up from behind and passed us. MG sailed almost 12 hours that night giving up 3+ knots in speed, and lost more sailing with reefed main after replacing the halyard the next morning, spotting PY almost 5 hours. PY finished with the new record, 4.5 hours ahead, in a time that should stand up for years. This was the year for a record, with strong winds almost all the way and that big boost by the Gulf Stream's wild meander. |
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| Predicted winds, predicted positions and actual positions of IMS 9 fleet at second position report, 0800 on 6/16. By this time the low had moved NE out of the way of the fleet, and another was on its way east from the mouth of the Chesapeake. Winds were now strong from the southwest (red vectors to 30 knots), backing more to the south and slackening somewhat approaching Bermuda. PY was now in first, some 46 nm ahead of MG, followed closely by BO. Blue Yankee (BY) and Brightstar were at identical positions, some 8 nm ahead of MG. MG overtook these two to finish third, but even at top speed could not have caught PY at this point. BY corrected out first, both in IMS 9 and in the fleet overall, but PY got the record. |
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| A key to the success of all these boats was accurate knowledge of the Gulf Stream, and all but Boomerang were Local Knowledge clients, with Blue Yankee, Pyewacket and Morning Glory all using LK's "Force 4" routing engine as well as current predictions. |
| CLASS WINNERS USING LOCAL KNOWLEDGE ROUTING AND/OR CURRENTS
Class 2: Aura (2) |