Plan for the weather you might get.
Every forecast is one version of what might happen. Most sailing apps take that version, find the fastest route through it, and hand you a single answer. ProSail routes your race or passage through the whole range of forecasts, then shows you the plan that still works for the weather that’s expected.
Why ProSail
The hardest decisions at sea are rarely about where the boat is. They’re about what route works best for the expected weather, and how it could change. You make those judgements with a forecast you know won’t be exactly right, and you have to decide how much risk or time to take.
Forecasters already know this. The big weather centres run their models dozens of times with small changes, and the spread between those runs shows how sure they can be that day. Almost none of that reaches the skipper. ProSail is built to put it in front of you in plain language.
It’s also built to be simple. Expert routing software can do almost anything, but it takes a navigator and an afternoon to work it out. ProSail asks a few questions and runs the numbers. What comes back is a decision you can talk through with your crew.
How we think about planning
- Plan against the forecast range
- We route every plan through around fifty versions of the forecast and show you how many of them it works in.
- Pick the plan that works for you
- The fastest route in the most likely weather is not always the best choice. We show which option wins most often and which one protects you when things go wrong.
- Start from your limits
- For a passage that means your crew’s comfort, such as wind, sea state, beating and darkness. For a race it means how much risk you want to take. The plan starts there.
- Say how sure we are
- When two options are within a whisker of each other we say so, because a single route presented as certainty is worse than no advice.
- Show what the alternatives cost
- If you’d rather take the other route, you should know what it’s likely to cost and when it might pay.
- The skipper decides
- ProSail is decision support, not an autopilot. It doesn’t replace a passage plan, local knowledge, seamanship or your other tools.
- Check afterwards
- After each race we publish what the forecasts said and what actually happened. For your own passages, the same honest review comes from your track, and each one teaches ProSail a little more about your boat.
Who’s behind it
I’m Alastair Norman. Over the last 20 years I’ve run crewed charters in the Channel, the Solent and the Med, and I hold the RYA Yachtmaster Ocean. My racing started in 2010, with three RORC Fastnet campaigns in 2011, 2013 and 2015, plus Cowes Week and inshore round-the-cans racing.
The decision that kept me up at night as a skipper was never the navigation. It was what route worked best for the expected weather and tides, what the crew could handle and how it could change. ProSail is the tool I wanted for that, and for the race decisions that come down to the same question.
ProSail is built by MuMu Media Ltd, my software company in the UK.
Forecasts: ECMWF open data (CC BY 4.0). Currents and tidal streams: Copernicus Marine Service. Coastlines: Natural Earth. Boat polars: ORC certificate data.