The insurance assessor wants to know your sea state at 14:30 when the incident occurred. You have a vague memory of Force 4 going Force 5, swell building from the south-west. What you don't have is a logged entry with pressure in millibars, precise wind speed and direction, and visibility at that specific time. You have your recollection, which is worth exactly as much as it is in a dispute.
A properly maintained ship's log is not a bureaucratic requirement. It's the record that protects you when the facts become contested.
The Navigation Record
Departure Port and Departure Time with Departure Port Location (GPS coordinates) anchor the passage start. Three waypoint fields — Way Point 1/2/3 with their respective position coordinates — document the route actually sailed versus the planned passage. Destination Port, Destination Arrival Time, and Destination Port Location close the navigation record.
For a coastal passage in UK waters, this navigation structure handles the typical round-trip structure of a weekend passage — from home port to a destination harbour with waypoints off headlands and through tidal gateways. The position coordinates turn a named waypoint list into verifiable trackable data.
High Water At Destination and Low Water At Destination capture the tidal picture at the arrival port — the two numbers that determine whether you can enter the marina at your expected arrival time or whether you need to adjust speed and timing. A skipper arriving at a drying harbour with an unexpected 1.2m tide needs this data from the pre-departure planning stage, not from memory when the approach is underway.
The Weather Record as Legal Documentation
Sky State, Precipitation, Wind Speed (kts), Wind Direction, Visibility (metre/Miles), Sea State, Temperature (c), and Pressure (mb) together create the meteorological record that MCA guidance recommends be maintained in a vessel's official log.
The pressure field (millibars) is the field most recreational logbooks omit and most professional requirements include. Pressure trend over a passage tells you whether a system is building or clearing — a drop of 8mb in three hours during a coastal crossing is actionable weather intelligence. Logged at departure and arrival, it provides context for the sea state and wind observations.
Cruise Notes is the narrative log — the entry that records what the passage actually felt like, what decisions were made and why, what the crew encountered. It's the complement to the structured data fields, providing the qualitative context that numbers alone can't carry.
The Engine Log Is the Maintenance Record
Total Trip Time (hrs), Total Trip Time (mins), Engine Hours, and Trip Distance (nm) together build the running log that drives scheduled maintenance. Engine service intervals are measured in running hours, not calendar months. Without an engine hour log, you're either over-servicing or under-servicing — both expensive.
Fuel Usage (litres), Fuel Added, and Fuel Remaining create the fuel management record that makes range calculations accurate rather than estimated. A skipper who knows their consumption averages 8 litres per hour at cruising speed, with current fuel remaining at 60 litres, has a reliable range estimate. One who doesn't log fuel has a guess.
Crew Names is the last field — simple and often overlooked. In the event of an incident requiring RNLI response or subsequent investigation, the crew manifest is the first thing emergency services request. Having it logged takes thirty seconds. Not having it when needed is not an option.