Currents — Overview
Currents are one of the most exciting — and humbling — additions to FairWinds. This page covers what they are, where they show up, and what to expect the first time you sail through one.
What Are Currents?
Ocean currents are large, persistent flows of water moving in a consistent direction and speed. Unlike wind, which changes constantly, major ocean currents are semi-permanent features of the ocean — the Gulf Stream has been flowing northeast along the US East Coast for as long as ships have sailed it.
In FairWinds, currents are modeled from real oceanographic data (GRIB files) and updated on the same forecast cycle as the wind. They affect your boat's actual position over the ground — pushing you sideways, helping you along, or working against you — regardless of what your heading and sails are doing.
If a race or expedition has currents enabled you will see an extra addition to the wind controls in the bottom right of the race viewer.
- 1-click: show the currents as a colored gradient
- 2-click: show the currents as arrows
- 3-click: turn current view off
The strength and direction of the current (the 'set' and 'drift') are shown wherever you hover your mouse.
Where Currents Are Active
Currents are enabled in several global, regional and local regions:
| Region | Current | Character |
|---|---|---|
| English Channel + Ireland | Tidal currents | Strong, direction reverses with tide |
| Western Atlantic | Gulf Stream | Fast, northward, warm — a sailor's highway or nemesis |
| South Africa | Agulhas Current | One of the world's strongest — notorious for rogue waves |
| East Asia | Kuroshio Current | The "Black Current" — Japan's equivalent of the Gulf Stream |
| Eastern Australia | East Australian Current | Flows south along the coast — the EAC from Finding Nemo |
These are enabled on a per-race basis, as the discrection of the race creator.
What You'll Notice
The first thing most sailors notice in a current race is that their boat isn't going where they're pointed. Your heading might be 045° but your actual track over the ground is 070°. That gap is the current pushing you.
The direction of the current is the 'Set'
The stength of the current is the 'Drift'
In FairWinds you'll see this both in a new reckoning line (the 'current' line - a blue line) and in your compass as a blue arrow, and in your instruments
-
The reckoning line drifting away from your heading arrow — the reckoning line shows where you'll actually end up, not where you're aimed.
Here's an extreme example crossing the Gulf Stream. Note your boat needs to point 20°+ to reach the destination:
The Key Mental Shift
In wind-only sailing, heading = path. Your boat always follows the straight line in front of it.
In currents, heading ≠ path. You need to aim somewhere other than your destination so that the current carries you onto the right track. How far off you aim depends on current speed, boat speed, and direction.
Current turns navigation from a one-variable problem into a vector problem — and that's where the skill and fun come in.
Where to get Currents
The current grib files are found on the same wind page:
Where to Go Next
Routing with Currents → — how to download current GRIBs, read the compensated heading, and avoid the common traps.