How to Choose the Right Anchor

Choosing the right anchor is one of the most important equipment decisions a boat owner makes. An anchor that is too small, the wrong type for the seabed, or poorly matched to the boat's displacement can drag in the night — with serious consequences. This guide covers the main anchor types, how holding power works, matching anchors to seabed conditions, and sizing an anchor correctly for your boat.

Why anchor choice matters

An anchor is the single piece of equipment standing between your boat and the shore when the engine is off. In calm conditions almost any anchor will hold, but when the wind picks up at 2 AM and the tide changes, the differences between anchor types become critical. A well-chosen anchor set in good holding ground can hold a boat in 40 knots of wind. A poorly chosen one may drag in 15.

The key factors in anchor selection are the anchor type (design), the weight relative to the boat, the seabed conditions where you typically anchor, and the scope (ratio of chain rode to water depth). No single anchor works perfectly in all conditions, which is why many cruising boaters carry a primary anchor and a backup.

Main anchor types

Danforth (fluke) anchor

The Danforth, or fluke-style anchor, uses two flat flukes that pivot and dig into the seabed. It excels in soft bottoms — mud, sand, and silt — where the flukes can bury deeply. The Danforth offers excellent holding-to-weight ratio in soft ground but struggles on hard sand, weed, or rocky bottoms where the flukes cannot penetrate. Danforth anchors are lightweight and easy to handle, making them popular as secondary anchors on smaller boats. They are also common on bowriders and day boats that anchor in sandy coves.

CQR (plow) anchor

The CQR, or plow anchor, has a single pivoting fluke shaped like a farmer's plow. It sets reliably in a wide range of seabeds — sand, mud, weed, and gravel — making it a versatile all-round anchor. The CQR was the standard cruising anchor for decades and remains widely used. Its hinged shank allows it to reset if the boat swings with tide or wind shift. The main drawback is that it can be slow to set in very soft mud and may not penetrate hard pan.

Rocna (roll-bar) anchor

The Rocna is a modern roll-bar anchor that has gained a strong following among cruising sailors. The roll-bar ensures the anchor always lands in the correct orientation, and the concave fluke design provides fast setting and high holding power in most seabeds. The Rocna outperforms traditional plow anchors in independent tests, particularly in weed and hard sand. Its main drawback is the bulky roll-bar, which can make it harder to fit on some bow rollers. See our used boat buying guide for more on evaluating anchor gear when purchasing.

Bruce (claw) anchor

The Bruce, or claw anchor, was originally designed for offshore oil rigs. Its three-claw design allows it to set in most seabeds and reset reliably if the boat swings. The Bruce is forgiving and easy to handle, but its holding power-to-weight ratio is lower than modern designs like the Rocna. It remains popular on motor yachts and flybridge cruisers where a bow roller can accommodate its shape.

Spade and other modern anchors

The Spade anchor uses a sharp tip and concave fluke to achieve fast setting and deep penetration. Other modern designs — the Manson Supreme, the Vulcan, and the Mantus — offer similar performance characteristics with different shank and fluke geometries. All of these modern anchors significantly outperform older designs in holding power per kilogram.

Matching anchors to seabed conditions

No anchor works in every seabed. Understanding the bottom where you anchor is essential:

• Mud and silt: Danforth and fluke anchors excel. Plow and roll-bar anchors also work but may need more scope to dig in.
• Sand: Almost all anchors perform well in firm sand. Rocna and Spade designs set fastest. Soft sand can be tricky for plow anchors.
• Weed: Roll-bar and spade anchors cut through weed to find holding below. Danforth anchors tend to skip over weed without setting.
• Rock and coral: No anchor holds reliably on rock. A grapnel or small fluke anchor can lodge in crevices, but this is not secure holding. Avoid anchoring on rock when possible.
• Hard pan: Spade and Rocna anchors can penetrate hard seabeds where older designs bounce off the surface.

Sizing your anchor

Anchor sizing is based on boat length and displacement, not just weight. A 40-foot sailing yacht displacing 8 tonnes needs a substantially larger anchor than a 40-foot motorboat displacing 4 tonnes. Most anchor manufacturers provide sizing charts that account for both dimensions.

As a general rule, cruisers often size up one category from the manufacturer's recommendation. The cost of a larger anchor is modest compared to the cost of a grounding. A typical 40-foot cruising yacht might carry a 20-25 kg Rocna or CQR as a primary anchor, with a 15 kg Danforth as a backup.

Chain vs rope rode

The rode — the line connecting the anchor to the boat — affects holding power. All-chain rode is heavier and keeps the anchor shank flat on the seabed, improving holding and absorbing shock loads. A rope-chain combination is lighter and easier to handle but provides less holding in rough conditions. For boats that anchor frequently in exposed conditions, all-chain rode with a snubber is the standard choice.

Carrying a backup anchor

Most experienced boaters carry at least two anchors: a primary for routine anchoring and a backup (often a different type) for different seabed conditions or emergency use. A common combination is a Rocna or CQR as primary with a Danforth as secondary. For more on essential boat equipment, see our boat buying checklist and boat safety equipment guide.