Home / Seamanship / Navigation on board
The plotter shows where you are. Not why
Electronic navigation is good, and it fails. A flat battery, a wet unit, an update at the wrong moment. If you also know where you are, you notice within the minute. If you do not, you notice later.
Chart, course, dead reckoning
Course over ground out of heading, tidal stream and leeway. Dead reckoning is not a museum piece but the fallback when the screen goes dark: heading, speed and time give you a position good enough for the next harbour.
Bearings and fixes
Two bearings on fixed objects cross at your position, three make a small triangle and show how carefully you worked. The same bearing on two lights every half hour at night tells you whether the anchor is holding.
Buoyage
In IALA region A, red is to port when entering. Cardinal marks run clockwise, north, east, south, west, and the cones are the memory aid: two points up is north.
The collision regulations
Rules of the road, lights, sound signals. The three questions are always the same: can I see him, can he see me, and who gives way to whom. A boat under engine is not a sailing vessel, even with the sails up.
Tides, stream and weather
Tide tables before letting go, not after. Read the barometer through the day, because it is not the reading that counts but the change. Cloud and the Beaufort scale give you the order of magnitude before the phone signal confirms it.
The log book
Position, course, weather, engine hours, anything out of the ordinary. Variation and deviation are worked in, otherwise the series does not add up. A log book is the one record on board that nobody can reconstruct afterwards.
What this has to do with insurance
After a loss the log book is the best evidence you have: it shows weather, position and time, and it shows them in a sequence that was written before the loss. With us there is more to it: our blue water cover requires the digital NAMMERT log book once the boat moves more than 300 nautical miles from its reported location. Keeping it meets a contractual duty and at the same time produces the document that counts in a claim.
