Polars and targets

1 Where they live, and who can change them

Open Boats. Each row ends with Polar, Targets, Calibration and Sails. The first two are this guide. That row is the only way in.

Both pages are written by admins and owners and read by everyone, and neither is billing-locked — the same gating as boat management. Setting a boat up is not something a lapsed subscription should stop you doing.

2 The polar

A polar is the boat’s target speed at every wind speed and angle. It is the yardstick behind percent-of-target in the player, the %tgt row on the video HUD, and the sail performance trend. Without an active one, all of those simply have nothing to measure against.

Three of them: Nav, Perf and Start

The page opens on a Nav / Perf / Start row of tabs, and everything under them belongs to the tab you are on — the drop area, the pills, the grid. Nav is the polar the product has always had: laylines, board times, target speed, the tuning guide, and what Race Control reads on the boat. Start is the boat accelerating out of a slot, which is a different set of numbers, and an owner who exports both from the same tool now has somewhere to put the second file.

Perf is the sheet the boat is judged against rather than the one it is steered by: percent-of-target in the player and the sail performance trend both measure against it. Leave it empty and they measure against Nav — which is where every boat stands until someone uploads one, so an empty Perf tab changes nothing and is not a thing to fix. Keeping the two apart is worth something the day you retune a target you sail to: with a Perf sheet in place, that edit no longer quietly re-levels a season of the numbers you were graded on.

The three are independent. Each keeps its own sources, its own active selection and its own grid, and none can move another’s numbers — uploading a start polar changes nothing the debrief prints. Leave Perf and Start empty and nothing about the boat changes.

Uploading one

Pick the tab first, then drop the file. Three formats, all auto-detected. You do not pick which is which.

1. Drop the file on Drop a .pol, Expedition table, or VPP CSV, or click to browse. Up to 2 MB.
2. That is the upload. There is no submit button and no preview — picking the file does it, and the notice tells you which kind was detected and how many rows came in.
3. If it did not become the active source automatically, press Activate on its pill.

That is what makes trying a new polar cheap: upload the VPP output beside the measured one, activate it, look at a race, and switch back if you do not like the answer. Nothing was overwritten — re-uploading only replaces the rows of that same kind.

With nothing active the page says so in as many words, and that role’s lookups are off across the product until you fix it — with the one exception the tab itself names: an empty Perf is measured against Nav, not measured against nothing.

Checking it landed right

Under the pills, the grid shows the active source’s own rows: TWS (kt), TWA (°) and Target BSP (kt), with a wind-speed filter to narrow it. Pick a wind speed you know the boat at and check a row or two. It is thirty seconds and it catches a unit mix-up before it quietly makes every percentage wrong.

Clear on a pill deletes that source and its rows. If it was the active one, the confirm says so — clearing it leaves the boat with no active polar for that role until you activate another, and no other role steps in. It names the role too: the other roles keep their own sources. The exception is Perf, and its confirm says which one it is: clearing the last Perf source measures the percentages against Nav again.

Target speeds between two grid points are interpolated over wind speed. Targets and interpolation has the rule, including what happens past the ends of your table.

The start model

The Start tab carries one more panel, under the grid: three small tables Expedition keeps beside the polar, describing how the boat changes state rather than how fast it goes when it is not changing.

Each is a function of a different quantity, so each table has its own column axis — and only the first of the three is indexed by wind at all.

Each row takes its own file — up to 64 KiB — and each upload replaces that table whole; the other two are untouched, including their own column axes, which are separate exports measuring different things. The panel prints the parsed matrix back so you can see the numbers that landed, with the upload time and the shape beside the heading. Delete returns one table to never-uploaded and leaves the rest alone.

Until August 2026 this page and the panel described all three tables from inference rather than from Expedition’s documentation, and described them wrongly — acceleration as seconds, brake as metres, and both of the lower two as functions of wind speed. The stored numbers were never touched and nothing on the platform computed with them, so no file needs re-uploading; only the labels above were wrong.

3 The tuning targets

This is the sheet on the bulkhead: rig and trim prescriptions indexed by true wind speed. Forestay at 12 knots. Rake at 18. Which kite. Nordic Stars keeps it per boat, per mode, and reads it at the wind you actually had.

The page holds two tables, stacked — a panel headed Upwind and one headed Downwind. There is nothing to switch between; scroll to the one you want.

Columns are free-form and class-agnostic. Your table is your table: your column names, your row of wind speeds, your vocabulary.

Starting a table

An empty mode offers a Columns box, prefilled with a sensible set for that mode as comma-separated names. Edit it to your own and press Create upwind table (or Create downwind table). Then add rows.

If the crew already keeps these numbers in a spreadsheet, do not type them again — section 5 is the shorter road.

Rows, columns and saving

• Add a row — put the wind speed in Add row at TWS and press Add. Rows keep themselves in wind order, and a duplicate wind speed is refused.
• Edit a cell — click and type. It saves when you leave the cell; Enter is the fast way out, Escape puts the old value back.
• Add a column — press Add column in the panel head, type the name and press Add: it is appended as the last column, blank in every row, and it carries the chip its name earns straight away (section 6), so widening a table no longer means re-importing one.
• Rename a column — press Rename column in the panel head, pick the column and type the new name: the column keeps its place in the table and every value already under it.
• Delete a column or a row — the × in its header or at the end of its row. Both confirm and both name what goes.

The panel head tells you where a save is: Saving…, then Saved. If one fails, your typing stays on screen and a Retry appears beside the message — nothing is discarded behind your back.

Clearing a table

Clear table empties the mode entirely, and the confirm counts what it is about to delete. Deleting the last column does the same thing and says so, because a table with rows and no columns is not a state that exists.

4 Cells that are words

A target cell holds a number or a word. Max, A1.5, 3.9-4.2, 96/100 — whatever the sheet on the boat says. Just type it.

Words behave differently from numbers, deliberately:

• Numbers interpolate between the wind speeds either side of the one you had.
• Words step. A word holds from its row until the next row that has one — which is exactly how a sail selection works. You do not fly half an A2.
• Words are never graded. The player shows them as written and offers no verdict, because a named sail has no deviation to measure.

A cell holds at most 20 characters; longer text is refused and the cell goes back to what it held. Anything the app cannot read as a plain number stays a word verbatim, including things that look like arithmetic — 1e3 is the word 1e3, not a thousand. Guessing there would be rewriting your data.

5 Importing the team’s own sheet

Import CSV in the panel head of either mode. It replaces that mode’s whole table in one go.

What the file needs: a header row, and its first column must be the true wind speed. Everything else is up to you. Commas and semicolons are both understood — Excel writes semicolons in comma-decimal locales, and the sniffer works out which you have.

1. Press Import CSV and pick the file.
2. Read the preview. Each column shows the header exactly as your file spells it, a box with the name it would be stored under, and its channel chip.
3. Rename any column you want to. This is the moment to wire one up — section 6.
4. Check the sample rows, then press Replace the upwind table and confirm.

Problems are listed under the columns. Some block the import and say exactly which line and column they mean — no wind-speed column, no data rows, a cell over 20 characters, two rows at the same wind speed, an unnamed column, two columns with the same name. Fix the file, or fix the rename boxes, and the confirm button comes back. Anything not blocking — a stray cell past the last header, say — is listed as ignored rather than acted on silently. Past eight issues the list summarises the rest.

One parsing rule worth knowing: a decimal comma is read as a decimal point only in a semicolon-separated file. In a comma-separated one, a quoted “8,3” stays the word 8,3 — because guessing there would change your numbers.

Taking the table back out

Export CSV in the panel head downloads that mode’s table in the shape described above — wind speed first, then your columns in their order, words as written, blank cells empty — so an exported file imports back without editing, and the table you have been editing is a file the crew keeps.

6 The chips on your column heads

Every column head wears one of two chips, and they answer a question the product owed you for a long time.

Exactly five column names are wired, and this is the whole list:

So a column called bs is target only and a column called bsp is graded live — same number, different answer. Rename it to wire it up, or keep your own word and keep it plain. Both are legitimate; the chip just makes the choice visible instead of invisible.

7 Where all this shows up

• The debrief player’s tuning guide — one tile per column, at the live wind, with the boat’s own value under each target. The debrief player walks it.
• Percent-of-target in the player and on the video HUD — that one is the polar, not the tables: the Perf grid, or Nav while Perf is empty.
• Race Control’s TARGETS tab — the same sheet, same column names, live at the helm. Race Control on the boat.
• The sail performance trend, which measures against the polar and deliberately not against the tuning tables — the wind-angle conventions differ, and mixing them would make the percentages quietly mean something else.

Change a table and the change is live everywhere immediately. There is nothing to publish and nothing to re-run.