A log book was originally used with a “chip log” to record and determine the distance a vessel travelled over an amount of time. The reading of the log was recorded at specific times (hourly or half hourly) giving the distance travelled, which presented after a little calculation of tide, an estimated position.

 

Now that we have the benefits of reliable GPS, the modern use of a logbook has grown to contain other bits of information to record whilst on passage. A short list of the information inserted into the logbook on a daily basis is presented below:

 

Name of the vessel

Tides of major and local ports

MMSI / Call sign of the vessel to use in emergency

Passage and pilotage plans with information passed to the local Coast Guard

Forecasted and current weather information including, cloud coverage and wave heights

Course steered

Dolphin / Whale sightings

Latitude and Longitude GPS positions (Marked in pencil on the paper chart)

Log readings

Engine rev / temperature log readings if needed

Engine checks and notes of any leaks

Crew on board and details of their next of kin

Details of any changes (course steered) or major issues or incidents

Log entry every hour or half hourly

 

The list is not exhaustive but gives an idea as to the information input with a pen and not a pencil (so that no changes are made at a later date).

 

The logbook is our black box on board and always taken with you in the event of the craft sinking, on fire or a collision. The Captain / skipper can then use it to prove to the insurance companies and authorities that you were professional and indeed truthful with regards to the correct passage taken and actions taken.

 

Leisure craft in foreign waters are often stopped and checked by local customs, and one item they do check is the logbook including last refuelling stop, due to the red diesel rules and regulations abroad.

 

The logbook is also used as a back-up (should your plotter and GPS systems shut down), you then have a known last position at a given time, course steered and speed. This is extremely useful if you are caught out in fog or away from sight of land.