Frequently Asked Questions

How can I add additional data (like heart rate) once a base log file has been uploaded?

To augment data or change any other settings that you made during the initial upload, go to the uploaded file (under Data) then click on the link "Uploaded by ... at ...", then select "Augment uploaded files". You will be able to add (or remove) files from the upload, and finally click "Update Data".

How do I access calibration info (e.g. difference between TWA tack to tack and HDG tack to tack and TWS upwind to downwind, etc)?

The Njord Analytics single boat report contains a calibration report which contains data to help with compass, paddlewheel and wind instrument calibration.

You can create a single boat report via the left hand panel, or via the cogwheel menu ("Edit Reports"). You will find the calibration report at the very bottom of the report main page.

Do you have an app that coaches can use for speaking in coach comments?

We offer text input for coach comments via Live Coach Tools — a mobile-optimised web app accessible from any smartphone browser, no download required.

For hands-free use on the water, consider using the dictation feature of your phone to let your speech be transcribed into a text comment.

Is it possible to see HDG-COG?

If you want to see a HDG-COG number in all chart types, you can calculate it like so:

Go to the uploaded data segment; select Process
Select Add Metric, then Custom Formula
Enter HDG-COG = Heading - COG
Press Apply

You can also see HDG-COG in the calibration report without performing the steps above.

My Velocitek is mounted on the cockpit side, how can I add 90 degrees to Heading to ensure that it is correct?

You can change Heading data like so:

Go to the uploaded data segment; select Process
Select Add Metric, then Custom Formula
Enter Heading = Heading + 90
Press Apply

Heading values will be re-aligned to the 0..360 degrees range after adding 90 degrees.

When setting up the course, is the bearing "from previous element" taken from the starboard end, port end, or middle of the line?

For course elements consisting of two marks (start line, finish line and gates), the center point between the two marks is used to calculate bearing from/to the previous/next course element.

What do I need to do to see an event in the performance database?

Events need to be added to the performance database first. Click on "Phases Database", then "New Phases Collection". You will be asked which races of that event to include (you could exclude practice races, for example, which is why events are not added to the performance database automatically).

Is there any way to output a GPX file of the race data?

Unfortunately, we don't support exporting data to GPX files yet. Supported export formats include CSV and Bravo file formats.

Does Njord Analytics run on iPad?

Njord Analytics runs on any modern browser, including on iPads.

Do you support yardstick / ratings?

No. Any calculations showing the rank of boats, such as in the Fleet Race Report, assume the boats are identical.

Do I need to recreate the report after changing a race's course?

You don't need to make a new report after adjusting the marks. Simply refresh the report page in your browser and the new course will apply.

How can I add sails, and delete old sails?

You can enter your sails, and enter new sails, in Njord Analytics using one of the 3 following methods:

On the water, use the live sail input page - it's accessible when navigating to your boat and choosing Live Coach Tools
When selecting any race or training, go to the annotations view, click "Edit Sails Usage", you can enter new sails there
When using any software to record events on the water, such as Expedition or KND, you can import the events file with your log file and the sail changes from that file will show up

You can rename and remove sails on the Sail Database page.

How do I send a Njord Analytics report to my team?

You need to add people to the boat first, you can do that under Data, then select your boat, then Settings - Permissions and enter the team's email addresses there.

All users that have access to the boat will also be able to access the report by visiting Njord Analytics. You can also have them notified via email with a direct link to the report. To do that, go to the report, and click on the share button next to the title. Select the people you want to send the email to and click Send Notification Emails.

Is it possible to set a manual TWD for each leg?

You may enter a fixed TWD for the entire day when loading data, or, In Njord Analytics, you can also use the TWD inference feature.

You may also use the INTERPOLATED(SERIES(...)) Formula.

In the comparison with another boat, sometimes the boat that loses meters ("VMG gain") has a higher average VMG - why?

It's a different calculation... "VMG gain" is calculated from the start & end position, using the TWD (average TWD, from both boats) as the reference bearing. "Average VMG" that you see in the table above is taking each boat's TWA & Boatspeed, calculating the instantaneous VMG along the track, and averaging that. In principle the winning boat should have higher average VMG, but that is only true when there are no wind shifts during the tests and both boat's wind instruments are perfectly calibrated. This is rarely the case, that's why such a small deviation is not unexpected. Place higher trust in the "VMG gain" value in this case.

How can I add a boat to an event?

Option 1:

Go to the event
From the cogwheel menu (bottom right) select "Edit Event"
Add the boat to the "Boats" field
Click "Update"

Option 2

Go to the boat and select a relevant segment of uploaded data
Uncheck "Show events with boat only"
Find the event you want to add the boat to, and click "Add boat to this event"

See also: Comparing Multiple Boats for the broader context of multi-boat analysis.

Why are my maneuvers not being detected?

Work through these checks in order:

TWA data must be present. Open the Line Chart and add TWA. If it is missing or flat, add wind data first — see Adding Wind Data.
TWA must cross the trigger angle. A tack requires TWA to cross 0°; a gybe requires TWA to cross 180°. Use the Line Chart to verify TWA moves correctly around the maneuver. If it jumps without crossing (e.g. 30° to 330° without passing through 0°), heading data quality is likely the issue — see below.
Check the Upwind/Downwind TWA range in boat Settings → Filters. The boat must be sailing within the configured range for the full Exclude Time before and after the maneuver. For foiling boats, the default Downwind range (120–170°) is often too wide — lower it to match your actual downwind TWA.
Check the data sample rate. Maneuver detection requires at least one sample every 3 seconds (0.33 Hz); 1 Hz or higher is recommended. GPX files from smartwatches often record at only one sample per 5 seconds — configure the device to record at 1 Hz.

Why are maneuvers detected but not analysed?

Enable "Include maneuvers without full analysis" and "Extended data" in the Maneuvers view settings. A "Reason Not Analyzed" column appears explaining why each maneuver was skipped.

Common causes:

Too close to another maneuver. Analysis requires (Average Time Before + Exclude Time Before) seconds of clean sailing before the maneuver, and likewise after. Back-to-back maneuvers within ~30–40 seconds will often be skipped.
TWA outside the configured range at the Exclude Time point before or after the maneuver. Widen the range or increase the Exclude Time.
Boat speed below ~2 knots.

Note: maneuvers cannot be added manually. The fix is always to adjust detection settings or correct the underlying data.

My heading data looks wrong — TWA and maneuver detection are broken

If a self-contained GPS device (Sailmon, Velocitek, Vakaros) is not mounted facing straight forward on the centreline, recorded Heading will be offset and all derived TWA will be wrong.

Option 1 — drop Heading and use COG instead:

Go to the uploaded data segment → Process → Drop Metrics → select Heading
Add a Derived Metrics step — Njord will recalculate TWA from TWD and COG

Option 2 — apply a fixed offset for a known mounting angle:

Go to the uploaded data segment → Process → Add Metric → Custom Formula
Enter Heading = Heading + 90 (adjust the angle to match your mounting)
Heading values are automatically re-aligned to 0–360°

For Vakaros specifically: if the device is mounted more than ~10° off the centreline, Njord will reject the Heading channel automatically with a "Heading appears invalid" warning and fall back to COG.

How do I recalculate metrics after changing an input (boatspeed, heading, calibration)?

When you want to substitute one channel for another (e.g. use SOG instead of BSP, apply a speed offset, or recalculate TWA after fixing Heading):

Go to the uploaded data segment → Process
Select Drop Metrics and drop all derived metrics that depend on the changed input — typically TWA, TWS, VMG, and any downstream metrics
Apply your correction: Add Metric → Custom Formula (e.g. BoatSpeed = SOG or BoatSpeed = BoatSpeed + 0.5)
Add a Derived Metrics step to recalculate the dropped metrics from the new base

Note: Applying a formula twice applies it cumulatively. Use Reset to Uploaded Files on the Process tab to start over from the original data.

Why is my TWD inference producing wrong results mid-day?

TWD inference works best with clean straight upwind/downwind sailing, clear tacks and gybes, and consistent wind. When it drifts mid-day:

Limit the inference time range to start at the first start
Enter an initial TWD seed value (e.g. the bearing of the first start line)
For significant mid-day wind shifts, re-run inference separately for each segment with its own wind conditions rather than covering the whole day in one pass

With multiple boats loaded into the same event, inference is more reliable — the algorithm uses combined maneuver geometry across all boats.

If inference fails entirely, try "Weather Data" or a manually entered constant TWD. Defining a full race course (all marks) also helps — leg boundaries from mark roundings are more robust to wind shifts than TWA-based detection.

Polar targets are not appearing or look wrong

Verify a polar is set as default. Go to boat Settings → Polars and confirm one is marked as active.
Polars are applied at upload time only. Changing the active polar does not update previously uploaded data. To re-apply: go to the uploaded segment → Process → Reset to Uploaded Files (re-runs processing with the current polar). Or drop the polar-derived metrics and add a Derived Metrics step.
Enable targets in chart settings. In Scatter or Targets views, the polar targets overlay must be enabled via Chart Settings.

The start report shows incorrect BelowLine values or bow position

Check your unit preference. BelowLine is displayed in meters or boat lengths per user preference — set at app.sailnjord.com/profile/settings. Two users can see different numbers for the same data.
Check the GPS antenna location setting on the boat (bow, centre, stern) — applied at upload time. After changing it, re-upload the log file.
Check for erratic Heading data. Start-line metrics rely on Heading to calculate bow position. If Heading is erratic, drop it via the Process tab — Njord will use COG instead.

Njord User Guide