| "Local Knowledge" offers a range of PC programs at different levels, each incorporating our detailed hydrodynamic current model of San Francisco Bay, based on and tested with current measurements over the past 7 years, and now the gold standard in SF Bay racing. |
| NEW-GENERATION TACTICAL SOFTWARE WITH 2007 SF CHARTS & CURRENTS |
| Local Knowledge now offers a range of PC programs at different levels, each incorporating our detailed hydrodynamic current model of San Francisco Bay, now the gold standard in SF Bay racing. The examples below are based on our "Force 4" tactical program, which is best used live onboard, monitoring the GPS and boat instruments. But our entry level "Force 2" program at just $200 contains the same current information, charts and many options to study currents and plan racing strategy. All programs come preloaded with BBS marks and courses. |
| Strong Bay currents have a major impact on laylines and route selection. The zero-current laylines are shown by the blue straight lines, and the current-corrected laylines by the magenta dots. In the example below it is more than 5 minutes faster to sail to the upwind mark (at Blackaller) via the lower layline (starboard tack to layline) than via the upper layline (port tack to layline). Our programs compute current at every point, and you can add as many current displaypoints as you like, zooming in on the race venue. The yellow boxes in the example have been added by the user. The flood currents shown range to 3.4 knots at the Golden Gate and vary sharply over the racecourse. |
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| San Francisco Bay currents are swift and change dramatically in direction from point to point. Local Knowledge PC programs enable you to study currents in advance and make printouts at a sequence of times to take along on the boat. Better yet, for boats that can operate an onboard computer, our currents are essential input to tactical software, such as our own "Force 4" and "Offchart Racer," and third-party programs such as Deckman for Windows. |
| NEW FOR SF BAY RACING ... LK now offers an intermediate tactical program called "Offchart Racer." This program includes the same routing engine used in Force 4 (the program used by top racers worldwide, including Oracle and Alinghi), but for a fraction of the price. "OR" reads wind grib files and our LK currents and applies your boat polars to compute the fastest (and comparison) routes, current-corrections to laylines and much more. OR was used to great advantage in the 2004 Pacific Cup, where Inspired Environment scored a big upset by taking a much more northerly route than its competitors, finishing a half day ahead. Just $695. |
| OR was used to compute the example below, taken at noon on 9/16/2004 near max flood. The blue vectors show the current during a leg from near Treasure Island to Harding Rock. The current causes a huge shift in the laylines (magenta dots compared to blue lines), partly due to set and drift and partly due to the change in effective wind direction due to the current. The routing solution produces an optimal (red) course and several comparison courses (other colors). The times for these routes are shown in the "Best Course Comparisons" box, color-coded to match the route (these all assume constant wind at 10 knots from 250 degT). The solution predicts a diffrence of almost 2 minutes on this leg from current alone. |
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