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Speed polars

Edit a polar and choose the primary polar

AdvancedUpdated

Edit a polar in Avelsta: drag the diagram points, correct the table, add angles or wind speeds, apply a percentage, overlay your sessions, save a version, set the primary polar.

The essentials

  1. Open Polars, then See details on the polar to edit.
  2. Diagram: drag a point to adjust the speed at that angle and wind.
  3. Table: click a cell to correct its value (in knots).
  4. Undo (or Ctrl Z / ⌘ Z) steps back, one change at a time.
  5. Click Save…: update the existing polar, or create a new one from these values.
Polar details: editable diagram and table
Editing a polar

Going further

The table

Action How
Correct a value Click the cell, type, confirm
Add an angle or a wind speed Insert button before or after a row or column
Remove an angle or a wind speed Delete button of the row or column
Scale the whole polar Type a percentage (for example 95) then Apply; applied for good when saving

In a generated polar, measured cells are blue and cells filled in from references are yellow.

Overlaying your sessions

The diagram’s Sessions menu shows the points of your sessions on top of the polar. It is the best way to see where the polar is too optimistic (points below the curve) or too cautious (points above), before adjusting.

Saving: update or create

Choice Effect
Update “name” The polar is updated; sessions whose POL was computed with it are recomputed
Create a new polar A new polar is created with these values; the current one stays as it is

Leaving the page with unsaved changes asks for confirmation.

The primary polar

Each boat has a primary polar, marked with a star. It is used for the polar percentage of sessions computed from now on.

  1. In Polars, on another polar of the boat, click ★ Set as primary.
  2. Confirm: the next sessions and imports will use this polar.

The POL of sessions already computed is not recomputed, so your sessions remain comparable. A boat’s first polar automatically becomes primary.

The list of polars, primary polar first
The boat’s polars

Deleting a polar

The Delete button of the details page. Sessions that referred to it are recomputed with the boat’s primary polar; if it was the primary, the most recent polar takes over.

Source sessions

A generated polar keeps the list of its source sessions, at the bottom of the details page. A source session deleted or merged since is flagged.

See also

  • Polar percentage (POL)The polar percentage compares the boat speed with its target speed at the same angle and wind. Computation, primary polar, recomputing sessions and interpretation.
  • Generate a polar from your sessionsCompute your sailboat’s measured polar from your NKE logs: choice of sessions, STW or SOG, measured cells, completion with similar reference polars, saving.
  • Import a polar (.pol, .csv, .txt) or start from a referenceAdd a polar to Avelsta from a .pol, .csv or .txt file, from the library of more than 510 reference polars, or by copying one of your polars. Accepted file format.
  • What is a boat speed polar?A sailboat’s speed polar gives the target speed for each true wind angle and true wind speed (TWA, TWS). Reading the diagram and the table, theoretical polar and measured polar.