The work a tug does at walking speed
A ship approaching a berth needs more than less speed. A harbour tug puts force at the right point on the hull while rudder, wind, tide and towline limits shape the final movement.
A place for slower thoughts
Harbour Notebook
Ports, tides and the measurements that connect ships to shore.
Words by Maya Rook
The archive
5 storiesFrom the notebook
Reading a seabed through sound
A sonar return is a measurement, not a picture of the ocean floor. Turning it into a useful chart means accounting for the water, the moving vessel, and what the echo cannot identify on its own.
The long journey of a container number
A container number moves from painted steel into gate, vessel and shipment records. Its check digit catches some bad readings; the journey still depends on reliable events and a match to the box.
Why a ship carries water it will later discard
Ballast water steadies a lightly loaded ship, then leaves as cargo comes aboard. The same voyage can move living organisms between ports, making the contents of a tank as important as its weight.
The zero beneath a harbour
Chart datum connects a sounding to a tide height. Its local reference, time period and uncertainty explain why the zero beneath a harbour needs a name.