Anchoring

A boat at anchor is only as safe as her ground tackle and the way it is set. The two ideas that matter most: lay out enough scope so the pull on the anchor is along the seabed, not upward – and choose ground that actually holds. Try the scope calculator.

Scope ratio (rode : depth)

–

Rode to veer–
Pull angle–
Holding–

Know your hooks

Different anchors suit different seabeds. A cruising boat often carries a main “bower” plus a second anchor of a different type for mixed ground. One device below is the odd one out – a drogue, which works in the water, not on the seabed.

Fluke / Danforth

High in sand · mud

Light and flat with huge holding for its weight in sand and mud. Poor in weed or rock and slow to reset if the wind shifts.

Plough / CQR

Good all-round

A hinged ploughshare that buries itself. A long-trusted all-rounder, though it can be slow to dig in.

Delta

Good all-round

A fixed, one-piece plough. Sets quickly and resets well – a popular bow-roller anchor.

Claw / Bruce

Reliable setting

Sets easily in most bottoms at any angle with moderate holding. Struggles in soft mud and hard sand.

Scoop · Rocna / Spade

Excellent

Modern concave “new-generation” anchors. Set fast and hold extremely well across most seabeds – today’s favourites.

Fisherman

Rock & weed

The classic stocked anchor. Lower holding for its weight, but one of the few that hooks into rock, weed and kelp.

Grapnel

Dinghies · rock

Folding hooks for dinghies and small boats, or for snagging rock. Little holding in soft ground.

Drogue

Heavy weather · drag

Not a seabed anchor at all – a cone of tough fabric streamed astern on a bridle in a survival storm. It drags through the water to slow the boat, stop her surfing down wave faces and hold her stern-to the seas. Its cousin the parachute sea anchor streams from the bow instead, to hold her nearly stopped and bow to weather.

Dropping the hook

1

Choose the spot

Shelter from the expected wind, room to swing a full circle, and a holding bottom – check the chart and note the depth and tidal range.

2

Work out scope

From depth + bow height + tide, decide how much rode to lay (use the calculator above). Allow more if wind is forecast.

3

Approach head-to-wind

Motor up slowly into the wind to your spot and bring the boat to a stop.

4

Lower, don’t throw

Lower the anchor under control as the boat drifts back, paying out rode steadily so it lies along the bottom.

5

Dig it in

With the scope out, snub the rode and let the drift – or a touch of reverse – drag the anchor until it bites and holds firm.

6

Check it holds

Take a transit ashore or watch the plotter. If it drags, recover and start again – never trust a doubtful set.

Weighing anchor

1

Shorten in

Motor slowly up toward the anchor, taking in rode as you go so it never comes under heavy load.

2

Break it out

When the rode is straight up and down, the boat’s momentum or a gentle motor ahead breaks the anchor free of the bottom.

3

Recover & stow

Bring it up, wash off the mud, and stow anchor and chain securely for sea.

4

If it’s stuck

Snub it and motor slowly ahead to trip it. A tripping line rigged to the crown beforehand frees a fouled anchor.

What lies beneath

The chart marks the nature of the bottom – S sand, M mud, Wd weed, R rock. Anchor where you can actually dig in.

  1. SandExcellentThe ideal bottom – anchors bury cleanly and hold hard.
  2. Firm mud / clayGoodReliable holding once the anchor is well dug in.
  3. Soft mudFairHolds, but let the anchor soak in and use extra scope.
  4. Shingle / gravelFairVariable – the anchor may drag before it finds a bite.
  5. Weed / kelpPoorThe anchor skates over the top. Find a clear sandy patch.
  6. RockUnreliableMay not dig, or may jam fast. Use a tripping line to recover.

Anatomy of an anchor

Ring / shackle Stock Shank Crown Arm Fluke
Rode
The whole length of chain and/or rope connecting boat to anchor.
Chain
Heavy links that lie on the seabed; their weight keeps the pull horizontal and resists chafe.
Warp
A rope rode, often with a short length of chain at the anchor. Lighter and cheaper, but needs more scope.
Snubber / bridle
A stretchy line taking the load off the windlass and absorbing snatch as the boat sheers.
Bitter end
The inboard end of the rode – always made fast to the boat so you can never lose the lot.
Windlass
The deck winch that raises and lowers chain and takes the strain of weighing anchor.