Comparing Multiple Boats

When two or more boats sail together on the same day and their data is loaded into Njord, the analysis becomes much richer than what is possible from a single boat alone. This page covers why multi-boat data is so valuable, how to set it up, and the licensing scenarios that come up most often.

Why compare multiple boats

The decisive moments are the stretches where two boats "line up" — sailing close together, on the same tack, in essentially the same wind. In those windows you can attribute a speed or height difference to the boats themselves rather than to wind shifts or pressure differences, which is something you can never do with single-boat data alone.

Beyond pure lineups, multi-boat data also lets you:

  • Cross-check wind readings between boats — a TWS or TWD discrepancy often points to a calibration issue on one of them
  • Compare maneuver execution side by side — same conditions, different techniques
  • Use one boat as a reference while testing rig, sail, or trim changes on the other
  • Get more reliable TWD inference — the algorithm uses combined maneuver geometry from all boats

Almost every view type in Njord Analytics supports multiple boats. The most useful for direct comparison are:

  • Map — overlaid tracks; the Ladders tool draws lines between the boats' positions at equal times for a clear visual lineup
  • Statistics / Gain Loss — gain/loss between two boats broken into forward, sideways, and VMG components
  • Line Chart — overlay any metric (boatspeed, TWA, heel…) from all boats on the same axes
  • Scatter Chart — reference areas highlight each boat's mean ± standard deviation for quick visual comparison

Getting set up

Two things have to be true for you to compare boats in Njord Analytics:

1. You need access to all the boats

Access is granted per boat. If you created the boats yourself in your own account you already have it; otherwise the owner of the other boat needs to add you as a user on their boat. See Sharing Boat Access.

Each boat keeps its own list of permitted users, so sharing in both directions takes two steps: you add the partner team's email to your boat's permissions, and they add your email to theirs. Once both are done, both teams can see both boats.

Tip — finding the right contact on a partner team: Knowing that "boat X is on Njord" usually isn't enough to set up sharing. You need to identify the person on that team who manages their Njord account and the exact email address they use. It may be the owner, a coach, or a designated team member, and the boat itself may be named by sail number, full name, or sit under a coach's account — so you can't reliably guess the email from the outside. The fastest way is to ask the team directly: "Who handles your Njord account, and what email does it use?" Then exchange email addresses so each side can add the other to their own boat's permissions.

2. All the boats need to be in the same event

When the second (or third) boat's data is uploaded, it usually lands in a new auto-created event by itself. Add it to the existing event rather than creating a new one — analysis only works across boats that share an event.

There are two ways to do it:

Option A — from the event:

  • Open the event
  • Cogwheel menu (bottom right) → Edit Event
  • Add the boat to the Boats field, click Update

Option B — from the uploaded-data page of the second boat:

  • Open the uploaded-data page for the boat
  • In the Events list, uncheck Show events with <boat> only
  • Events for other boats you have access to will now appear, each with an Add <boat> to event button

License considerations

Once you've decided you want to compare with another boat, the practical question is who pays for what. The right setup depends on how the boats are owned and how the teams work together.

Fleet, club, or federation buying for several boats

A single Njord account holds the license, and that license covers all the boats in the fleet (e.g. an Olympic squad's coach account, or a club account for its J/70s). Adding more boats to the license unlocks volume pricing — the per-boat price drops as the fleet grows. The boats are all created under the same account, with team members added per boat as needed.

This is the simplest setup for any group where one entity has overall responsibility for the fleet's analytics.

Independent owners sharing data with each other

Each owner has their own Njord account and their own boat. Owners then grant each other access via Sharing Boat Access, and at the end of each sailing day each owner uploads their own data to their own boat. Everyone with shared access then sees all boats in Analytics (and can pull them into Njord Player for debriefs).

In this setup each owner pays for their own boat's usage independently — daily, monthly, or annual, whichever fits their schedule (see Setting up Payment). Volume discount does not apply across separate accounts; it only applies when multiple boats are billed to the same account.

If the partner team only uses Njord Player and not Analytics: sharing through Analytics isn't available to them, so log files have to be sent manually after each day, and each team needs its own Player license for the boats whose data they want to load. In special cases a custom arrangement may be possible — please contact us.

Two boats owned by the same team for in-house testing

Both boats belong on a single license under one account. This unlocks the two-boat volume discount and keeps all the data in one place, ready for direct comparison.

If you're not sure which scenario fits your situation, contact us — we'll help you set it up.