Does every ship do this?
No. Dynamic positioning needs suitable equipment and power. Other vessels may drift where safe, maneuver, or anchor in a suitable location.
Episode guide
How do ships stay in place without anchors?
In deep water, an ordinary anchor may be impractical. A suitably equipped ship can use dynamic positioning: sensors measure its position and heading, and a computer coordinates thrusters to keep correcting drift.
How it works
Watch episodeYouTube
How it works
POSITION-HOLDING LABSYSTEM ON
TARGET POSITION
CURRENTTHRUST CORRECTION
Conceptual illustration, not a navigation simulator.
Questions, answered
Is the ship perfectly still?
No. Position-holding does not remove heave, roll, or pitch from waves. Strong conditions or equipment failures can exceed the system’s limits.
Why not just use a longer anchor chain?
Depth is only one constraint. The anchor needs a suitable seabed and pull angle, and the machinery must recover the hanging chain and anchor. Specialized deep-water moorings are a different system.
Sources & further reading
Primary sources explain the engineering. Reddit links show audience questions, not technical proof.
Keep following the question
Episode guide