Types of Marine Anchors: A Complete Guide for Yacht Owners

There are seven main types of marine anchors in common use: the plow (CQR), delta, Danforth (fluke), Bruce (claw), mushroom, grapnel, and navy (admiralty) anchor. Each is engineered for specific seabed conditions, vessel sizes, and anchoring scenarios. For marine yacht anchors specifically, the plow, delta, and Danforth designs dominate because they offer the best combination of holding power, resetting ability, and compact stowage for recreational and cruising vessels. Choosing the wrong anchor type for your seabed can result in dragging — one of the leading causes of vessel groundings and collisions at anchor.

How Marine Anchors Work: The Basic Holding Principle

All marine anchors hold a vessel in place through one of three mechanisms: penetration and burial into soft seabeds (sand, mud, clay), hooking or snagging on rocky or hard substrates, or dead weight for very low-current environments. The holding power of an anchor is not solely a function of its weight — a well-designed 10 kg plow anchor buried in firm sand can generate holding forces exceeding 1,000 kg, far beyond its own mass.

The rode (the chain or rope connecting the anchor to the vessel) plays an equally important role. A horizontal pull angle at the anchor shank keeps the flukes driving downward into the seabed. This is why a minimum scope ratio of 5:1 (chain) to 7:1 (rope) — the ratio of rode length to water depth — is recommended for reliable holding in most conditions.

Type 1: Plow Anchor (CQR and Variants)

The plow anchor, most famously produced under the CQR (Coastal Quick Release) trademark, is one of the most widely used marine yacht anchors worldwide. Its design features a single asymmetric fluke shaped like a ploughshare, hinged at the shank to allow the anchor to pivot and reset when wind or current causes the vessel to swing.

Performance Characteristics

• Best seabeds: Sand, clay, and firm mud — the plow drives deep and buries completely, creating high resistance.
• Resetting ability: Good — the hinged shank allows the fluke to reorient as the vessel swings up to 360°.
• Stowage: Fits neatly in a bow roller, making it the standard choice for yachts with a dedicated anchor fitting.
• Weight range: Typically 7 kg to 45 kg for recreational yachts. A 15 kg CQR is commonly specified for vessels up to 12 metres LOA.
• Weakness: The hinge joint can become a point of wear and may allow the anchor to skate across the surface before setting in very soft mud or kelp-covered seabeds.

Type 2: Delta Anchor

The delta anchor is a fixed (non-hinged) plow-type anchor with a weighted tip that causes the anchor to roll onto its point immediately on contact with the seabed, initiating faster burial than the CQR. Developed in the 1990s by Simpson-Lawrence, the delta has largely replaced the CQR on modern production yachts due to its superior setting speed and holding power.

Why the Delta Is a Top Choice for Yacht Anchors

• Setting speed: The weighted tip and fixed geometry mean the delta sets reliably in under 5 metres of drag distance in firm sand, compared to 10–15 metres for some hinged designs.
• Holding power: Independent tests have shown delta anchors generating holding forces of up to 150× their own weight in firm sand — significantly above the 50–80× ratio of traditional plow designs.
• No moving parts: The fixed shank eliminates the hinge wear issue of the CQR.
• Bow roller compatible: Like the CQR, the delta stows on a standard bow roller for easy deployment and retrieval.
• Weakness: Less effective in rock or coral, and can struggle to reset in very soft mud where it may skate rather than penetrate.

Type 3: Danforth (Fluke) Anchor

The Danforth anchor uses two large flat pivoting flukes mounted on a central stock to achieve burial through penetration. When horizontal tension is applied, the flukes rotate downward and dig into the seabed, burying the entire anchor. Danforth anchors are celebrated for their exceptional holding power relative to weight — among the highest of any anchor type in sand and mud.

Performance in Different Conditions

• Best seabeds: Sand and soft mud — the large fluke area provides exceptional penetration and burial depth.
• Holding power to weight ratio: A 4.5 kg Danforth can generate holding forces exceeding 450 kg in firm sand — a ratio of approximately 100:1.
• Stowage: The flat profile stores easily against the hull or in a dedicated deck bracket, making it popular as a kedge (secondary) anchor even on yachts that carry a plow as their primary.
• Weakness: Poor resetting ability — if the vessel swings 180° and the rode wraps under the anchor, the flukes can break out and the anchor may not reset. Also performs poorly in rock, clay, and thick kelp.

Type 4: Bruce (Claw) Anchor

Originally designed in the 1970s for anchoring North Sea oil platforms, the Bruce anchor features three curved claws that give it a distinctive appearance. The claw geometry allows it to set in any orientation and reset readily when the pull direction changes — a key advantage in tidal anchorages where vessels swing through 180° between tides.

Strengths and Limitations

• Versatility: Performs reliably across sand, mud, rock, and coral — one of the few anchor types with broadly acceptable performance in mixed or unknown seabed conditions.
• Resetting: Excellent — the three-claw design almost always presents a holding surface regardless of the pull angle.
• Holding power: Moderate compared to plow and delta designs. A 10 kg Bruce typically generates around 400–600 kg holding force in sand, compared to 700–1,000 kg for a delta of the same weight.
• Weakness: The claw profile does not bury as deeply as plow or fluke designs, so it can be dragged in very strong currents or storm conditions where other anchor types would remain set.
• Stowage: The three-dimensional claw shape does not fit cleanly in a standard bow roller and requires a purpose-designed fitting or anchor locker.

Type 5: New-Generation High-Performance Anchors (Rocna, Spade, Mantus)

Since the early 2000s, a generation of engineered high-performance anchors has entered the market, drawing on computational fluid dynamics and seabed mechanics research. These anchors — including the Rocna (New Zealand), Spade (France), and Mantus (USA) — combine elements of the plow and fluke designs to achieve faster setting, deeper burial, and higher holding-power-to-weight ratios than any previous generation.

What Makes These Anchors Different

• Roll bar: The Rocna and Mantus feature a curved steel roll bar at the crown that ensures the anchor always lands fluke-down, eliminating failed sets caused by the anchor landing on its back.
• Concave fluke: The concave or scoop-shaped fluke creates a self-burying geometry — as horizontal load increases, the anchor drives deeper rather than pulling out.
• Holding power: Independent tests by SAIL magazine and Practical Sailor found Rocna and Spade anchors generating holding forces of 200–300× their own weight in sand — roughly double the performance of traditional plow designs.
• Seabed versatility: All three designs perform well in sand, mud, clay, and grass, and reset reliably through full 360° swings.
• Cost: Premium pricing — a 15 kg Rocna costs approximately $400–$600 USD versus $150–$250 for an equivalent traditional plow — but the performance advantage justifies the investment for offshore cruising yachts.

Type 6: Grapnel Anchor

The grapnel anchor features four or more rigid tines radiating from a central shank, designed to hook onto hard substrates — rock, coral, wreckage, or artificial structures — rather than bury into soft seabeds. It is the correct anchor choice for rocky coastal anchorages, reef diving platforms, and dinghy anchoring where a burying anchor would be unable to find purchase.

Grapnels are not appropriate as primary anchors for yachts anchoring in open roadsteads or tidal anchorages. They can become permanently snagged on underwater obstructions, and holding power in sand or mud is minimal. For small dinghies, kayaks, and tender craft, a 1–2 kg folding grapnel that collapses flat for compact stowage is a practical and widely used solution.

Type 7: Mushroom and Navy (Admiralty) Anchors

Mushroom Anchor

The mushroom anchor, shaped like an inverted mushroom cap, holds by suction and dead weight in soft silt and mud seabeds. It does not penetrate or hook — instead, it gradually sinks into soft substrate over time, building holding power through suction resistance. Mushroom anchors are used almost exclusively for permanent moorings, buoys, and light-traffic markers rather than yacht anchoring. A typical permanent mooring mushroom anchor weighs 100–500 kg and can hold vessels of 10–20 metres in moderate conditions once fully embedded.

Navy (Admiralty) Anchor

The classic admiralty or navy anchor — the symbol of maritime tradition — features a long stock perpendicular to the flukes that orients the anchor for penetration. Despite its iconic status, it is rarely used on modern yachts due to its awkward stowage (it cannot be stowed in a bow roller), risk of the rode fouling on the exposed stock, and the existence of superior modern alternatives. It remains in use in certain working vessel and traditional boating contexts.

Anchor Performance Comparison by Seabed Type

Sizing a Marine Yacht Anchor Correctly

Anchor manufacturers publish sizing guides based on vessel length overall (LOA) and displacement. These are minimum recommendations for normal conditions — for offshore passages, overnight anchoring in exposed locations, or storm preparedness, stepping up one size is standard practice among experienced cruisers.

Primary vs Kedge Anchor: Why Most Yachts Carry Two

Most experienced sailors carry a primary anchor — their main everyday anchor, typically a delta or high-performance design stowed on the bow roller — and a kedge anchor, a lighter secondary anchor stowed in the anchor locker or lazarette. The kedge serves several purposes:

• Freeing a grounded vessel: The kedge is rowed out by dinghy in the direction of deeper water and set, then the vessel is winched off using the anchor windlass or winch.
• Mediterranean mooring (stern-to): The kedge is dropped off the bow as the vessel reverses into a berth, holding the bow off the quay while stern lines are secured.
• Tandem anchoring in severe weather: A second anchor is set in line with the primary to double the holding power in storm conditions.
• Backup if the primary anchor is lost: Anchors can become permanently snagged on underwater obstructions and must be abandoned. A kedge ensures the vessel is never without anchoring capability.

A common and practical combination for a 10–12 metre cruising yacht is a 15 kg delta or Rocna as the primary anchor on chain rode, and a 7–9 kg Danforth as the kedge on a rope-and-chain combination rode — covering both deep-burial soft seabed and rocky conditions between the two designs.

Anchor Materials: Galvanised Steel vs Stainless Steel vs Aluminium

Marine yacht anchors are manufactured in three primary materials, each with distinct tradeoffs:

• Hot-dip galvanised steel: The most common and cost-effective choice. Provides good corrosion resistance in salt water when the galvanising layer is intact. Galvanising lasts approximately 5–10 years in regular saltwater use before re-galvanising or replacement is needed. Weight provides the necessary mass for setting.
• 316L stainless steel: Offers superior corrosion resistance and a polished appearance favoured on superyachts and prestige vessels. Approximately 30–60% more expensive than galvanised equivalents. Note that stainless steel can be susceptible to crevice corrosion if the anchor sits buried in anaerobic (oxygen-deprived) mud for extended periods.
• Aluminium alloy: Approximately 30–40% lighter than steel anchors of the same design, making aluminium anchors attractive for weight-conscious racing yachts and performance cruisers. However, aluminium anchors must be significantly larger (and therefore heavier in absolute terms) to achieve equivalent holding power, partially offsetting the weight advantage. Not recommended for permanent mooring use.