On the Water

Anchor & Docking

Every way a boat stops: at anchor, alongside a dock, on a mooring buoy or stern-to a quay. These guides cover the method from choosing the spot to setting the alarm, why anchors drag and how to tell before the boat does, the lines and fenders that keep a boat still alongside, the anchors and chain that hold it, and the regulations that decide where you may stop at all.

19 guides

Start here

How to Anchor a Boat

The complete method — spot, scope, lay, set, watch — with a pass/fail test at every step.

Read the guide

Setting the anchor

Dragging, and the night watch

Docking and mooring

Anchors and ground tackle

Where you may anchor

More in Anchor & Docking

Anchor & Docking: common questions

How much anchor chain should I let out?
Scope is measured from the bow roller to the seabed, not from the waterline: depth at high water plus the height of your bow. For all-chain rode, 5:1 is a working minimum in settled weather and 7:1 for an overnight stay or any forecast wind; rope rode needs more. The number depends on depth, not on boat length — a 10 m boat in 10 m of water needs the same scope as a 15 m boat in the same spot.
How do I know if my anchor is dragging?
The bearings to two fixed objects ashore change, the boat lies beam-on to the wind instead of head-to-wind, the chain goes slack and taut in jerks, or a GPS anchor alarm shows the boat outside the circle it should be swinging in. At night the GPS alarm is the only one of those that works while you are asleep, which is why it is set before the last person goes below.
What anchor alarm radius should I set?
Centre the alarm on the anchor, not on the boat, and set the radius to the chain you have out plus the boat's length plus a margin for GPS error — typically 10–20 m. Our anchorage pages give a recommended radius for each spot, from 40 m on a mooring buoy to 120 m in deep Mediterranean bays. A radius wide enough to ignore the swing is wide enough to ignore a drag.
What lines do you need to tie a boat to a dock?
Four: a bow line and a stern line to hold the boat against the dock, and two spring lines — one led aft from the bow, one led forward from the stern — to stop it surging backwards and forwards along it. The springs are the ones most people leave off, and they are the ones that stop the boat working its fenders to shreds overnight.
Can you anchor anywhere you like?
Broadly, in open water outside harbours, channels and marked no-anchoring zones, yes. In practice the exceptions are where most boats want to be: marine parks and reserves, seagrass (Posidonia) meadows across the Mediterranean, cable and pipeline areas, swimming zones in season, and any bay a municipality has filled with paid moorings. The chart and the local notice board are the two sources that count.
What is the best anchor for sand, mud and rock?
For sand and mud, a modern scoop or plough design (Rocna, Spade, Mantus, Delta) sized generously for the boat; for rock and weed, the same anchor with a trip line, because no anchor holds well in rock and the question becomes whether you can get it back. The right answer is usually one good primary anchor sized up one step from the chart, not three different anchors.

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