Why this app

Draft

Where it started

Until now I planned my passages with commercial products, mainly Weather4D. It is a great app, but I sail in the southern North Sea and the Channel, and there its routes very often ran straight through what is not allowed on the water: wind farms and traffic separation schemes, mostly. A route I cannot sail is not much of a plan.

The second thing that bothered me was the annual subscription for the weather models. I have a problem with that in principle. The meteorological services publish their forecasts free of charge. Charging a little for processing that data and keeping it available on servers is fair — WeatherRouting’s relay does exactly that. Charging for the data itself is not.

I looked at the alternatives:

• Navionics had automatic routes in its app and on its website. That feature has moved behind a hefty subscription, it never did weather routing — it was built around motor vessels — and in my experience the routes were disappointing.
• Weather services such as PredictWind and Windy offer routing too, but behind subscriptions as well.
• OpenCPN is my main navigation software, and I am a great fan. It also has a weather routing plugin, which I have tested, but I find it hard to use and rarely do. And while OpenCPN is actively maintained, its architecture is dated. I’m realy hoping that a modern version will be built that uses most of the OpenCPN core as it is today, but adds a UI in a browser so we can use the complete modern controls ans libraries available today.

I am a great fan of open source. The weather data is free; the routing methods were worked out by academics and published for everyone. So why should routing cost money? WeatherRouting is my attempt at an app that is free and works for me, as a sailor, in reality.

How I sail

I sail mostly in Europe. During long weekends or single weeks that means short trips to England, France, the Channel Islands, the south coast of England and up the English east coast. Once a year a longer trip takes me further: Brittany, the Scillies, Scotland, or the Nordic countries — Denmark, Norway, Sweden and the Baltic. The long trips I mostly sail single-handed.

That shapes the app. A single-handed sailor in busy waters needs a route that respects the rules of the water, and a plan made before leaving that still holds when there is no internet at sea. My main concerns are to estimate aspects of a trip:

• What is the weather like?
• High winds, no wind, seastate?
• Durations, arrival times: I want to be “upstream” of the tidal current when approaching a destination in light winds.
• Recalculate a route while underway.

What WeatherRouting has to be

• Free. The app is free and stays free.
• Open data, from the source. The forecasts, currents and tides come straight from the services that publish them openly. These pages explain each source and its limits.
• Respecting the rules of the water. A route has to keep out of wind farms, cross traffic separation schemes as the rules require, and keep a sensible distance from the coast.
• Working offline. The app runs on the boat’s own computer, and the routing needs no internet. Getting new forecasts must work with as little connectivity as possible — through the relay, which cuts the data down to your area, or even by email through Saildocs.
• Leaving the judgement to the sailor. Where a choice is a matter of seamanship — how close to the coast, how to cross a traffic lane — the app has a sensible default that you can change.

What it costs

The app itself is free, and if you download the models yourself, directly from the weather services, it costs you nothing.

Two parts do cost money to run: the relay, which fetches and trims the forecasts for you, and the online version. Both need capacity in a data centre, and I pay for that. For now that is fine. If the app comes into wide use, a small fee for the relay and the online version will be needed to cover those costs — never for the app, and never for the data.

Who it is for

For anybody who is interested. For now it is being tested in a small circle of friends; later it will be open to anyone.

What it is not

Caution

WeatherRouting is strictly a planning aid. It is not a chart plotter and not for navigation. Always check a route against an up-to-date official chart and the official tide tables before you sail it.

WeatherRouting shows no official nautical charts, and that is deliberate. Navigational charts carry copyrights and licences that go against the principles of this app. I briefly considered including them, but it is not a viable option. The chart objects the router respects come from OpenStreetMap and OpenSeaMap instead — see Charts and zones.

About the name

“WeatherRouting” is not a creative name: it simply says what the app does. It may well change one day, suggestions are welcome.