Literally thousands of apps will give you a weather forecast, but just a few dozen are designed for sailors and few of them offer genuine routing. A basic routing algorithm is built into the main navigational chart brands, but this is only enough to avoid the land – not to optimise passage times or comfort. For a reliable ETA that can see ocean currents and understand efficiency at different points of sail you need something more powerful.
There are two elements to a dedicated routing app. While still connected to high-speed internet ashore, you can use the weather routing software to advise on the best moment to set off, crunching detailed weather, wave and tidal data for days in advance. Then, once offshore, you’ll be relying on satellite data, which typically means far less bandwidth (see box-out on page 63), so you need very efficiently packaged GRIB files.
Seapilot
Originally developed to cover Swedish waters, the designers have long since broadened the app to cover popular cruising areas around the globe. Its core is an engine that can process chart data to plot a safe route, but it also combines this with weather and tide routing for optimal passage planning. You can also plug in your boat’s polars to get greater accuracy. The basic app is free, which gives you simple real-time navigational capabilities, but if you want the full weather and tide routing, you’ll need to pay for the €39.99 Premium subscription. And while the app works on official S57 electronic charts, as used commercially, you can also buy charts in-app. Prices vary from nothing in
