With version 3.85 of Seapilot for iOS (iPad/iPhone), the app offers access to a new navigation tool for Weather routing, using GRIB- and POLAR-files. This will assist sailors to plan an automatically optimized route with input from wind- and current forecast data in combination with your vessel’s specific sailing properties. (During 2016 same tool will be implemented also in Seapilot for Android and for Windows).
By combining data from a GRIB file with a POLAR table, Seapilot can present a recommended optimal route over open water – with virtual waypoints as course-changes necessary for adapting to changing wind and current over time.
The input values are Time, Wind- and Current forecast and the vessel’s specific sail performance, as well as two manually defined coordinates: Start and Finish. Other depth-related parameters regarding land, shoals and soundings in the chart, as well as the vessel’s actual depth, are subject to further app development. The tool is therefor aimed at weather optimated auto-routing, or ”Sailing Weather Routing” in open sea.
The navigation tool Weather routing costs SEK 499 / EUR 53,50 / USD 59,70 when purchased in your Seapilot user account on www.seapilot.com. After purchase-registration, the app settings will display new options for GRIB, POLAR as well as Optimal – set Start/Finish. NB. The Weather routing tool also requires the tool ”Marks, Routes and past Track” registered in your account.
GRIB files (GRIdded Binary) consist of wind/current-forecast data for a defined area during a certain forecast period. Such GRIB files may be downloaded or ordered from several weather services on Internet. Imported into your Seapilot-app, the GRIB file will create a matrix with arrows directly on chart, where you visually may follow the arrow changes by moving a timescale for corresponding forecast period. The GRIB file may also be updated for each new forecast period made public.
A POLAR file is, in this context, a wind performance profile table for a certain type or model of a sailing vessel, indicating optimal angel and velocity in relation to different wind speed intervals in the table.