PredictWind Help Center

How to Change Weather Routing Settings

Routing preferences can be set from the top of the weather routing page.

 

NOTE: To save any of these settings you must click on the "Calculate Route" button

Optimise for Fastest Time

This will optimize the route for the fastest possible time.

Optimize for Comfort

This will optimise the route for the fastest time, but avoid high wind/wave regions in the forecast. You set your criteria for high wind and wave areas to avoid when you select ‘Comfort.' The minimum values for Wind Speed and Swell are 25knots and 2.5m. We do not allow lower values, as the optimal routes can be very long, trying to avoid these conditions.

Land Avoidance

Land avoidance is automatically enabled in the standard and professional packages.  The routing algorithm automatically avoids the land. The land avoidance uses 50m resolution data which will give great results in most cases. Please check all your waypoints are in the water for best results. You will also need to check the route does not cross the land, or any shallow areas, and is fit for navigation.

Polars

Polars define the performance of the yacht/power boat in different wind/wave conditions. It is important to define this accurately, so the optimal route is correct.

Polar Speed Adjustment

You have the option to adjust the polar speed by a percentage. If, for example, you are delivering a boat short handed and expect the boat performance to be slow by 20%, please apply 80% to the Polar Speed Adjustments.

Predefined

A list of popular yachts are listed. Select the closest yacht from the drop down list as well as motoring speeds below a certain wind speed if you are cruising or delivering a racing yacht.

Power Polars

This allows you to define a polar curve for a power boat. Simply fill in the boat speeds for the different conditions, and the performance curve will be calculated.

Sail Polars

Similarly this allows you to define a basic polar curve for a yacht. Simply fill in the boat speeds for the different conditions, and the performance curve will be calculated.

Advanced Polars

Allows you to edit and save your own custom polar curve to match the performance of your boat. Simply change the numbers, being careful to keep the same format, and spacing. Please use spaces not tabs.  The polar will be automatically saved after you perform a routing.

You can add extra colums/rows so long as you respect the same format.

Tws Twa, Bsp, Twa, Bsp, Twa, Bsp

4 0 0 47 3.59 60 4.3 110 4.36 141 3.26
6 0 0 45 4.99 60 5.93 110 6.13 143 4.67
8 0 0 43 5.89 60 6.93 110 7.21 146 5.77
10 0 0 41 6.39 60 7.44 110 7.82 150 6.57
12 0 0 40 6.63 60 7.71 110 8.29 155 6.99
14 0 0 39 6.75 60 7.87 110 8.64 165 7.19
16 0 0 38 6.82 60 7.98 110 8.89 168 7.6
20 0 0 38 6.91 60 8.15 110 9.43 170 8.38
25 0 0 39 6.98 60 8.27 110 10.36 168 9.45
30 0 0 41 7.01 60 8.32 110 11.04 157 11.62

Tws = True Wind Speed

Bsp = Boat Speed

Twa = True Wind Angle

The 4th and 5th Columns define the upwind target boat speed and true wind angles. The last two columns define the downwind target boat speed and true wind angles.

Wave Polars

Wave Polars adjust the boats performance depending on the wave forecast. This table allows you to adjust performance of the boat in all wave conditions. Use a % factor for the boat speed in the table below in various wave conditions. This is particularly important for light displacement boats.

The wave polars angles are the angle of the wave relative to the direction of the boat. ie 0 degrees is a wave approaching from the bow and 180 degrees is a wave approaching from the stern.

Tidal & Ocean Currents

If this option is selected the routing algorithm uses the tidal & ocean currents to find the fastest or most comfortable route. The data is displayed in the routing results - graphs, and currents tab.

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