27th Aug 2025
An anchor is one of the most essential pieces of safety equipment on board. Whether you’re pausing for lunch in a quiet bay, waiting out a tide, or seeking shelter in a blow, your anchor is what keeps you safe, secure, and exactly where you want to be. But with so many types and sizes available, choosing the right one for your boat can feel daunting.
In this guide, we’ll cover everything you need to know about anchors: from the different designs and how they work, to how to size them correctly for your boat and cruising grounds.
Why Anchors Matter
An anchor isn’t just about convenience - it’s a vital safety tool. A reliable boat anchor gives you confidence to stop in unfamiliar waters, ride out changes in tide and wind, and even deal with emergencies such as an engine failure near shore. Selecting the right anchor means balancing holding power, seabed conditions, weight, and ease of handling.
The Main Types of Anchors
Over the years, many anchor designs have been developed, each with strengths and weaknesses. The best choice for you depends on your boat type, the seabeds you frequent, and whether you want an everyday anchor, a storm anchor, or a kedge (secondary) anchor.
Plough Anchors
Plough-style anchors, such as the CQR and Delta, are extremely popular. Their plough-shaped fluke buries quickly into sand, mud, and gravel, making them versatile all-rounders. The Delta, in particular, is widely used as a primary anchor on cruising yachts and motorboats thanks to its strong holding power and self-launching design.
Claw Anchors
Best known through the Bruce design, claw anchors set quickly and are easy to handle. They hold well in a wide range of seabeds, especially sand and mud, though they may struggle in thick weed or very hard ground. Many motor cruisers favour claw anchors for their reliability and relatively compact shape.
Fluke Anchors
Fluke anchors, also called Danforths, are lightweight with wide, flat flukes that dig in quickly to sand and mud. They offer excellent holding power for their weight, making them popular as a kedge anchor or for small boats. However, they perform less well in weed or rocky ground.
Modern Scoop Anchors
More recent designs, such as Rocna and Spade anchors, have become the gold standard for cruising sailors. These anchors feature a concave, scoop-like design that digs in deeply and reliably. They reset quickly if the boat swings with the tide, and they hold strongly in a wide variety of seabeds. For long-distance or liveaboard cruisers, modern scoop anchors are often the first choice.
Grapnel Anchors
A grapnel is a traditional multi-pronged design, often used on very small boats, tenders, or for temporary anchoring on rocky bottoms. They are compact and cheap but offer limited holding power compared to modern anchors.
Matching the Anchor to Your Boat
Anchor choice isn’t one-size-fits-all. The right anchor depends on your boat’s size, weight, and how you use it. Manufacturers provide sizing charts based on length and displacement, but there are some general principles worth keeping in mind.
For dayboats, tenders, and small inflatables, a lightweight fluke or grapnel is usually sufficient. For cruising yachts and motorboats, most owners choose a plough, claw, or modern scoop anchor as their primary. The general rule is to err on the side of slightly bigger and heavier - an oversized anchor may be harder to stow but will give you far more security if the wind pipes up.
It’s also wise to carry more than one anchor. A smaller kedge anchor can be invaluable for manoeuvring, kedging off, or anchoring from the stern, while a heavier storm anchor provides peace of mind for serious cruising.
Considering the Seabed
Not all anchors perform equally across different seabeds.
Sand and mud:
Most anchors perform well, but ploughs, flukes, and modern scoop anchors are particularly effective.
Weed:
Thick weed can stop anchors from penetrating. Modern scoop anchors with sharp flukes, like the Spade or Rocna, tend to perform best.
Rocky ground:
Anchors may struggle to dig in at all. A grapnel or a heavier plough may be the best option, but in rocky areas, anchoring is always more difficult.
Gravel or shingle:
Holding can be variable. Heavier ploughs or modern scoop anchors are generally the best choice.
Knowing the conditions you usually anchor in helps narrow down your options significantly.
Chain, Warp, and Scope
An anchor’s holding power depends as much on the rode (the chain and warp connecting it to the boat) as on the anchor itself. For most cruising boats, an all-chain rode is ideal, as the weight of the chain keeps the pull on the anchor horizontal and improves holding.
If weight or locker space is an issue, a combination of chain and rope warp works well. In this case, the first 5-10 metres should always be chain, followed by nylon warp which stretches to absorb shock loads.
Scope refers to the ratio of rode length to water depth. A minimum of 4:1 is recommended in calm conditions, increasing to 6:1 or more in strong winds. Without enough scope, even the best anchor may not hold.
Tips for Choosing Your Anchor
When it comes to anchors, reliability is everything. If you’re torn between two sizes, always go larger. Think about your boating area: for example, an anchor that excels in mud may not be right if you frequently anchor over weed. Finally, consider how the anchor fits on your bow roller or stows in your locker. Some designs, like the Delta, are self-launching, while others may require manual positioning.
Final Thoughts
Anchoring is one of the joys of boating, whether it’s enjoying lunch in a peaceful cove or riding securely overnight in a quiet harbour. Choosing the right anchor for your boat means peace of mind, better safety, and fewer sleepless nights worrying about dragging.
At Pirates Cave Chandlery, we stock a full range of anchors - from traditional ploughs and flukes to the latest Rocna and Spade designs - along with all the chain, warp, and accessories you need. If you’re unsure which anchor is right for your boat, our expert team is always here to help you find the perfect match.
