Every vessel at sea is required to maintain a ship’s log—a detailed record of the vessel’s journey, environmental conditions, and onboard operations. A well-kept logbook is not just a formality; it plays a vital role in navigation, safety, and managing the boat’s systems and crew.

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⛵ 1. Why Keep a Ship’s Log?

Keeping an accurate navigation log helps the skipper:

• Track current and forecast weather and sea conditions

• Monitor vessel systems and onboard resources

• Aid in navigation by recording position fixes and course details

• Provide crucial evidence in case of incidents or investigations

• Maintain operational records for engine, fuel, and supplies

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📍 2. Essential Information to Include in a Ship’s Log

Regardless of the style or format of your logbook, the following details should be consistently recorded, ideally every hour or whenever a significant event occurs:

• Date and Time: Use local, ship’s time, or Universal Time (UT), clearly specifying which

• Vessel Details: Name, MMSI number, and radio call sign

• Crew: Number of persons onboard

• Ports: Departure port and destination, including high water (HW) and low water (LW) times and heights

• Distance and Speed: Water log (distance traveled) and water speed (log speed)

• Heading: Record true, magnetic, or compass heading—specify which

• Leeway: Estimate and log periodically

• Position Fix: From GPS, visual bearings, or buoyage

• Sail Plan: Current sails set and configurations

• Wind Conditions: True and apparent wind speed and direction

• Visibility: Clear notes on visibility conditions

• Sea State and Weather: Including cloud cover (noted as eighths, e.g., 5/8), barometric pressure, and weather forecasts

• Systems Monitoring: Battery charge, fuel tank levels, bilge condition, and water tank status

• Comments: Observations such as position relative to landmarks, expected tides, crew watch details, or any notable occurrences

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🛠 3. Additional Recommendations for Longer Voyages

For extended passages, it’s important to log additional operational data:

• Times water tanks are filled or changed

• Engine, generator, battery charger, and watermaker running hours

• Weather report schedules and satcom contacts with home or authorities

• Separate logs for vessel maintenance, defects, and crew health records

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🏆 4. Practical Tips for Effective Logging

• Record entries regularly and consistently—typically every hour on the hour

• Use clear and unambiguous language, noting changes in conditions or vessel status

• Set watch instructions, such as “Wake me if wind speed increases by 4 knots” or “Wake me if visibility drops below 2 miles”

• Keep your deviation and variation corrections handy when recording courses

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🚀 Final Thoughts: Why a Ship’s Log Matters

Maintaining a thorough navigation logbook enhances situational awareness and ensures your voyage is well-documented for safety and operational efficiency. Whether you sail for leisure or professionally, a detailed ship’s log is indispensable.