How It Works


  1. Vessel must have transmitting AIS with MMSI issued by flag state.
  2. Vessel must be able to send and receive email at sea. An InReach device is not acceptable.  Typically, HF radio with Pactor modem or Iridium Go!
  3. You must commit to sending a daily report via email when on passage.

Before Departure

  • 48 hours prior to departure, the Vessel captain files a FLOAT PLAN with detailed information about vessel, crew and intended voyage.

  • Passage Guardian programs to track the vessel using satellite AIS and establishes a weather route for the vessel using

  • Passage Guardian confirms via email, receipt of float plan and reception of AIS signals from vessel. 

On Passage

  • Vessel captain sends DAILY REPORT via email.  If the daily report is not received, Passage Guardian commences the Missed Check-In Procedure.

  • Passage Guardian checks progress using satellite AIS at least daily, and investigates causes of vessel off-course or stopped notifications (at any time).

  • Passage Guardian checks weather daily looking out 7 days, and alerts vessel (via email) to any heavy weather ahead.

 On Safe Arrival


Passage Guardian is a best effort service to monitor the progress of a vessel conducting a coastal or ocean passage.

Passage Guardian is provided free of charge, and offered without any warranty.

For the avoidance of doubt, Passage Guardian does NOT provide;

  • Distress, urgency or emergency communication
  • Weather forecasts, or weather routing services to vessels

I recommend engaging a professional meteorologist to provide a tailored weather forecast and best departure date. Most routers will also (on request) provide a route and send you updates whilst you are on passage.

Additionally, I recommend a subscription to PredictWind which I consider a "must have" aboard any cruising yacht.