This user guide covers Njord's two main products:

  • Njord Analytics, a web-based sailing analytics app
  • Njord Player, a PC and Mac app to combine video and data for a visual debriefing of your sailing day

Njord Analytics and Njord Player work well together, and some aspects work very similar in both apps. See Loading Boat Data.

For help with your user account, see Your Njord Account.

Make sure to use the search feature of this user guide (loupe icon above) to find relevant sections.

Getting More Help

In case this document does not answer your question, please contact us in one of the following ways:

Your Njord Account

To use either Njord Analytics or Njord Player, you need a Njord user account which is tied to your email address.

Login Form

Signing Up

  1. Visit and select Sign Up
  2. Enter your email address and a password of your choice
  3. You will receive an email with a confirmation code
  4. Enter this code in the signup form to complete the signup

When signing up fails, you may already have a user account with that email address, perhaps because someone invited you a while ago. In that case, try resetting your password (see below).

In Case You Don't Remember Your Password

  1. Visit and select Reset Password
  2. Enter your email address and click Reset Password
  3. You will receive an email with a confirmation code
  4. Enter this code and a new password of your choice to complete the password reset


Njord Analytics and Njord Player support the same types of files for loading data, and the process to load data looks the same in both Njord Analytics and Njord Player.

You can find the full list of supported data types at


The formula syntax below can be used to add calculated variables when loading data:

  • In the upload screen in Njord Player or Njord Analytics
  • In Njord Analytics, modify already uploaded data by selecting the uploaded data segment (Data section), and select Process
  • In Njord Analytics, configure one or more formulas to be applied every time data is uploaded to a certain boat. Set this up under Boat - Settings - Process


Heading - COGDifference between Heading and COG
DELTAPERSEC(UNWRAP(Heading))Rate of turn in degrees per second
DELTAPERSEC(BoatSpeed) * 60Acceleration in knots per minute
BoatSpeed / -(FILTER(DELTASEC(BoatSpeed, 10), DELTASEC(BoatSpeed, 10) < 0) / 10)When decelerating, how many seconds to zero knots at current 10 second deceleration average
INTERPOLATED(SERIES("2022-10-01T08:00+02:00", 10, "2022-10-01T11:00+02:00", 14))This could be TWS rising from 10 kts at 8 am to 14 kts at 11 am, for example


<Less thanTo be used with FILTER()
<=Less than equalTo be used with FILTER()
>Greater thanTo be used with FILTER()
>=Greater than equalTo be used with FILTER()
==EqualsTo be used with FILTER()
!=Not equalsTo be used with FILTER()
&Logical andTo be used with FILTER()
\|Logical orTo be used with FILTER()
!NegateTo be used with FILTER()


ABS(value)Absolute of value / remove sign
MIN(value1, value2)Minimum of two values
MAX(value1, value2)Maximum of two values
MOD(a, n)Modulo operation
SIN(value)Sine of value (which is expected to be in degrees)
COS(value)Cosine of value (which is expected to be in degrees)
FILTERPORT(value)Retains the value only on port tack (AWA between -170 and -10)
FILTERSTBD(value)Retains the value only on starboard tack (AWA between 10 and 170)
COALESCE(value1, value2)Choose value1 if it's not empty, else value2
SELECTPORTSTBD(valuePort, valueStbd)Select valuePort when sailing on port tack, valueStbd on starboard tack
UNWRAP(value)Removes wrap at 0/360 degrees, instead expands value below 0 or above 360 as needed for safe calculations
SHIFT(value, rows)Shifts value (series) by given number of rows
SHIFTSEC(value, seconds)Shifts value (series) by given number of seconds
DELTASEC(value, seconds)Delta of value compared to second seconds ago
DELTAPERSEC(value)Delta of value compared to previous datapoint, divided by number of seconds since last datapoint
ROLLINGMEAN(value, seconds)Rolling mean over second seconds
ROLLINGSUM(value, seconds)Rolling sum over second seconds
FILTER(value, mask)Filters value using the given mask, returning empty value where the mask is false
INTERPOLATED(value)Fill blanks between values by linear interpolation
INTERPOLATEDBEARING(value)Fill blanks between values by linear interpolation, correctly handling 0/360 degree wrap around
SERIES(time1, value1, time2, value2, ...)Produces a data series with the given values at the given times. Write times in ISO 8601 format with quotes, like "2022-10-01T10:00+02:00". Use with INTERPOLATED().

Note: all function names are case insensitive and may be written in lower case too.

Frequently Asked Questions

Is there a smoothing function for wind data? E.g. 5s, 10s, 15s, 30s averaging of wind coming from dinghy masts to remove noise?

When loading data and adding a wind data file (set file purpose: "Wind Data"), go to the file settings panel via the Info symbol in the uploaded files list. You can enter a custom amount of damping (in seconds) there.

Enter Damping for Wind Data


Njord Analytics is a web-based application that can be used from any modern browser and operating system. You can upload boat log data from anywhere, and share with your team.

Adding Wind Data

If there is no wind instrument on your boat that can be recorded in the boat's log file, there are 3 ways to add True Wind Direction (TWD) data to the analysis.

Setting TWD to a Fixed Value

Even when wind data is not otherwise available or cannot be inferred, adding a fixed values for TWD can enhance the data and provide TWA and VMG estimates. Choose "Use a fixed wind direction" in the upload form.

Adding in TWD from Other Sources

When sailing small boats, it can often be easiest to measure true wind from off the boat, such as from a coach boat or nearby buoy. Wind data can be uploaded in any of the supported formats (select File Purpose: Wind Data in the upload form).

Using Inferred TWD

Use the TWD Inference feature to let the system infer True Wind Direction throughout the day. It uses maneuver angles from tacks and gybes, and will also follow wind shifts when sailing straight. Having TWD data available (even if only estimated), unlocks features such as VMG gain/loss analysis which can be performed on any part of a test or lineup.

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, which you can do by accessing on your mobile phone.

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.

Input comments on the water

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

Calculate HDG-COG

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.

How can I cut a race from a long day's track?

The All Day view helps you to trim a long day's track into relevant training segment or races for further analysis.

  • Use the controls in the timeline to restrict the tracks displayed to the approximate time of the race you want to cut out
  • Click and drag on the lower part of the timeline to let the boats move along the track
  • Click on the track of the boat once to mark the start time, using recognizable maneuvers such as the prestart phase to guide you. As you hover over the track to find the end time, you will see a preview of the race track
  • Click on the track another time to mark the end time
  • Adjust the start and end time as needed, for example to round the start time to the full minute
  • Enter a name for the race and click Create

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:

  1. On the water, use the live sail input page - it's accessible when navigating to your boat and choosing "Live Coach Tools"
  2. When selecting any race or training, go to the annotations view, click "Edit Sails Usage", you can enter new sails there
  3. 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"


Njord Player is a document-based application. When launching the app, you will start with an empty document. It is recommended to add boat data and media assets from a single race or racing day to a document only, and create additional documents for other racing days.

To add content to a document, follow these guides:

Once data has been added, configure media playback in the main window and additional windows, and seek on the timeline to play back the race at any point in time.

Don't forget to save the document – this will allow to pick up after reopening the Njord Player app.

Import Boat Data

Method 1 - Loading Boat Log Files Directly in Njord Player

This method is recommended when you are not using Njord Analytics, or when your computer does not have an internet connection when you load data. See method 2 below when you are using Njord Analytics together with Njord Player.

To add boat log files to a document:

  • Open the Data screen by clicking the Data button in the timeline of the main window, on the Load Data button in the respective notification bar (see screenshot below).
  • Add a boat log file via the Add Log File button or by dragging it onto the view (read more about supported data sources.
  • Select the correct boat from the selection field. Boats are retrieved from your Njord Analytics account; you may add new boats directly from Njord Player by specifying a name and a boat class.
  • Click Use Data to confirm.

You may add multiple boats to the same document. This can be useful to show training partners or competitors in addition to the main boat. To do so, repeat the process above.

Adding boat log data to an empty document

Method 2 - Loading Data via Njord Analytics

This method is recommended when you are using Njord Analytics together with Njord Player. We recommend to load the relevant boat data in Njord Analytics first, as it is then straightforward to use the same data in Njord Player. In some cases support for new data file formats is also available in Njord Analytics first, requiring use of this method over method 1 above.

  1. Ensure that the boat's data has been loaded in Njord Analytics by you or another team member.
  2. From the menu in Njord Player, select File, then Download from Njord Analytics….
  3. Select the date that you want to download data for.
  4. Choose the boats that you want to download.
  5. Njord Analytics may also have race information that is useful in Njord Player (such as race start times, and course marks). Select an event to download races from.
  6. Click Download to confirm.

Import Media

Adding Media to a Document

To add media assets to a document:

  1. Open the media group configuration screen by clicking on the name of any media group (Video by default) in the timeline of the main window, or on the Add Media button in the respective notification bar (see screenshot below).
  2. Add one or more media assets via the Add Assets button.
  3. The asset file timestamp and the file time zone will be autodetected in many cases. If the autodetected values are not correct, you may change them using respective fields. Select multiple assets to change the time zone for multiple assets at the same time.

Adding media to an empty document

Supported Media Formats


Extensions: MP4, MOV

The file timestamp is taken from the capture date recorded in the video file (falls back to file creation date if unavailable).

When recording video using DJI drones, it is recommended to enable the Video Caption option and retain the generated .SRT files. These files will allow the Njord Player app to accurately detect file timestamp offsets that may be present in DJI video files.

When using newer GoPro models, select time stamp source QuickTime Time Code = Start of video in Njord Player to make consecutive clips align correctly.

Njord Player supports MP4 files using the AVC/H.264 codec or the HEVC/H.265 codec. Playing back videos in the HEVC/H.265 codec requires a faster computer than playing back videos in the AVC/H.264 codec. If you experience poor video playback performance, consider changing the camera setting to AVC/H.264.


Extensions: JPG, PNG

The file timestamp is taken from the photo capture date recorded in the file's EXIF tags (falls back to file creation date if unavailable).


Extensions: MP3, WAV, M4A

The file timestamp is taken from the file creation date.

Frequently Asked Questions

Does Njord Player support 360 degree-type video (e.g. from a Garmin Virb 360)?

Yes, 360 degree video is supported since Njord Player version 2.3.0. Add a 360 degree video and drag/pan the video using your mouse (also during playback).

Do you have a suggestion for a dictaphone, preferably with GPS for time stamping?

Phones (e.g. the iPhone Voice Recorder app) work great as a dictaphone because the timestamps are usually accurate with no effort required.

Other dictaphones work too, but you might have to set the time each morning for it to be accurate.

In any case, it helps to do an audible time countdown at the beginning of the recording, so you can verify the correctness of the recorded timestamp after you load the file in Njord Player.

How to I switch off the dual view in the main window?

From the menu, select View - Window Layout - Single View.

How do I share video with performance data overlays?

Njord Player does not support exporting video files with the performance data that you see on screen "burned in" (this is supported for photos, however).

If you need to share video and data, consider sharing the Njord Player file and video files together, which allows someone else with a Njord account to download Njord Player and view the video and data together.

If you really need it to be a video file, you could do a screen recording of Njord Player playing your video & data.

Does Njord Player run on iPad?

Njord Player does not run on iPad. It runs on Windows and Mac. Find the right download link for your platform on our Njord Player page.

I am moving video files off of my laptop onto a hard-drive (running out of space). Does this mean that Njord Player is now looking in the wrong place for the files? Do I have to re-import the media again?

We suggest to keep the Njord Player file (.sail2) in the same folder as your video. E.g., one folder per day usually works great. You can have sub-folders for video, but everything should be in the same top folder. You can then move that entire folder around and it's not going to be a problem for Njord Player.