| Transatlantic routing is too complicated to do in your head! Nowadays, all expert navigators use PC-routing software, which weighs wind, current and boat performance polars to predict the quickest route. The software determines the best route at the start, and corrects as you go, applying the latest wind and current data and computing from your actual position. Our router consistently predicted the best way to go, all around the Volvo Ocean Race .... | |
Local Knowledge Products & Services Local Knowledge specializes in detailed current forecasts for tidal and ocean waters around the world, plus top-rated routing and tactical software. During the DCNAC we will provide the following: 1. Tidal currents from Newport along Cape Cod and the Bay of Maine, around the north of Scotland and in the waters between Scotland and England and the German Bight, all the way to the finish near Hamburg. 2. Ocean currents across the Atlantic Ocean, comparable to but more extensive than those we provided in Leg 7 of the Volvo Ocean Race. 3. Our topflight "Force 4" tactical program, including the unique routing engine used by the top boats in every recent major ocean race. Or, alternatively, our mid-level "Offchart Racer" program, with the same routing engine and many of Force 4's ocean-racing features. Our router was featured in the leg-by-leg routing commentary of the Volvo Ocean Race in Seahorse Magazine by developer David Brayshaw. For his analysis of the 2002 Bermuda Race, CLICK HERE. 4. Current data in digital format to support displays and routing computations by third-party racing software, including MaxSea, Deckman for Windows and Raytech. FOR PRICING AND HOW TO ORDER, SEE BELOW |
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| The following examples assume Volvo 60 polars and use wind and current data from Leg 7 of last year's Volvo Ocean Race to illustrate routing solutions and ocean current predictions across the Atlantic. Our router is unique in that it computes quantitative alternative solutions for comparison (there are a variety of options to define computation of the alternative routes). Results are displayed in graphical form overlaying the electronic chart, along with a table showing time (in hr:mm) for each route. For easy interpretation, times are color-coded to match the route. The "red route" is always the fastest. | |
Routing Solution Without Current Input This example ignores currents but uses the actual wind forecast beginning at 1600 hrs UTC on April 29, 2002. Force 4 routes from a point shortly after the start off Newport to a point approaching the turning point at the north of Scotland. The optimal "red" route follows the greater wind intensity to the northeast (wind vectors are shown at time of start), and is some 37 hours faster than the more southerly "yellow" route. The optimal route during the actual DCNAC will of course depend on the wind forecast at the time, and also the current forecast (below) |
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| Same solution showing predicted boat positions (black dots) on the comparative routes several days later, at 0800 hrs UTC on May 3, 2002. The right-hand column of the 'Best Course Comparisons' box shows distance in nm from the dot to the destination point (just under 1300 nm for the boat on the optimal red route). Wind vectors are shown at that time and are more uniform than at the start. This allows variations in current to play a stronger role in the routing solution when current is included (see below). At the start, the routing solution is almost entirely driven by the wind. | |
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Routing Solution With Currents & Constant Wind This example shows the effect of variable current alone, using our predicted ocean currents on April 29, 2002, but assuming wind dead ahead along the rhumbline, at 15 knots from 65T. This direction is less favorable, and the magnitude is less than the average magnitude of the wind forecast, so the route takes longer. The route also follows the current pattern (see below) and is initially almost due east (compare to first example above). The router predicts a difference of up to 20 hours, based solely on differential current along the different routes. |
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Routing Solution With Currents and Wind The solution shown below puts all the data together, the wind forecast and our predicted ocean currents. The optimal red route is now some 6 hours faster than the zero-current solution (see first example above), and the portion in mid-Atlantic is more easterly. |
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| Detail of same solution in mid-Atlantic. The red vectors are current (see more detail in graphics below), and the red route is able to utilize the current flow to ENE at the upper right. As noted above, the winds in this portion are more uniform and from astern (gybing conditions), so the boat can take advantage of the favorable current without paying a significant penalty in reduced pressure or in sailing extra distance. | |
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| Comparison of solutions with (red curve) and without (blue curve) ocean currents. | |
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Current Predictions used taken during Leg 7 of Volvo Ocean Race - West Atlantic |
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Current Predictions used taken during Leg 7 of Volvo Ocean Race - MidAtlantic |
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Pricing & Options: 1. Ocean Data alone in format for LK or 3rd-party Software: $400 Note: the high-resolution tidal-current model for the coastal waters in the DCNAC is available only from Local Knowledge. Once purchased, it can be renewed each year for $250. 4. Force 4 Tactical Package: Force 4 program (list $2,000) and all current data at just $2,450. 5. Offchart Racer Ocean-Racing Package: Offchart Racer program (list $695) and all current data at just $1,150. LK can also provide electronic wind files, and even navigators. Contact us for details as follows: by email: info@goflow.com by phone (US): 415-332-8507 |
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