Jibe Apparent Wind Calculator

Did you ever wonder where the wind is coming from when you jibe? The answer is “it depends”. more>>.

Did you ever wonder where the wind is coming from when you jibe? The answer is “it depends”. Make sure to play with presets in the applet below.

  • The graph in the settings section plots the speed throughout the turn (not to scale :)), from initiation to exit
  • “dip” speed is needed to reflect the mid-jibe speed loss that is a result of carving
  • Wind blows into the dot
  • The applet does not show your rig’s apparent wind, which also depends on in which direction you are swinging it and how fast

If you are interested in physics of windsuring, see also Board/sail/sailor lateral force article at Ebb Tide Windsurfing.

[kml_flashembed movie=”/wp-content/uploads/2007/04/jibecalc6.swf” height=”490″ width=”415″ /]

4 replies on “Jibe Apparent Wind Calculator”

Hi Sergey, I posted a link to this on rec.windsurfing before you enabled comments.

Newsgroup contributor Florian F said,
“Wow, nice work.
The app is relatively self-explanatory, but a little help with the
specific terminology used and how it applies could be helpful. Also, the jibe radius is usually proportional to the speed at any given moment. It is of little consequence to the apparent wind, but it would be cool if the application could take that into account as well. And, perhaps, space the dots relative to speed.
That means he’d have to wrap the entire logic into an algorithm that calculates positions from the supplied parameters first, rather than calculate apparent wind angles relative to absolute positions, but it would be even more impressive.”

I’m confused but curious.

1. Which way is the board sailing in the graph? From bottom to top?

2. What is the significance of the red lines on the display?

3. The “trails” are the wind direction, yes? What is the advantage to turning them off?


The board is sailing from bottom to top.

The red lines show wind speed, entry speed and exit speed.

The “trails” show wind direction at periodically spaced points. If you turn them off, you will unclutter display for playing with “Time Position” slider.

Leave a Reply

Your email address will not be published. Required fields are marked *