How to Select the Right Anchor This piece was contributed by the National Safe Boating Council (NSBC). Organized in 1958, their mission is to reduce accidents and enhance the boating experience. The NSBC is the foremost coalition for the advancement and promotion of safer boating through education. To learn more about the National Safe Boating Council, visit their web site at SafeBoatingCouncil.org. "What anchor should I buy for my boat?" It is difficult to answer this basic question, even though anchors have been used for centuries to immobilize boats at sea. Anchoring involves many variables besides just the anchor, such as environmental conditions, anchor rode, and anchoring technique.  Anchors dig into the seabed to hold a boat in position. They serve a safety role by keeping boats out of the surf or off the rocks. They also allow boaters to secure the boat temporarily while fishing, having lunch or spending the night. When an anchor penetrates the surface of the seabed, suction created by the bottom material plus the weight of the material above the anchor, creates resistance. In rocky or coral bottoms, anchors can’t dig in, but rather snag on protrusions and hold precariously. The holding power of modern anchors is remarkable, varying between 10 and 200 times the anchor weight. This means that some anchors that weigh only 5lb. can hold in excess of 1,000lb.! But with widely varying conditions in the real world, how do you select the anchor that’s right for your boat? Anchor Attributes: Ideally, an anchor should possess the following attributes: Quick to set and re-set when the wind/current shifts. Good holding in all bottom types: sand, mud, rock, coral and grass. Strength – able to withstand high loads on any portion of its structure. Good holding power at short scope Easy to release from the bottom without damage. Compact to store on deck or in a locker. Alas, no single anchor possesses all of these attributes, but certain ones represent a good balance for given conditions. Size:   To state that a particular anchor has the “highest holding power” is an over-simplification in a world of highly varied bottoms and conditions. A 30-foot boat does not need an anchor of a certain weight; it needs an anchor of the appropriate size given the expected conditions. Physical size, rather than weight, is actually a better indicator of holding ability. As you might expect, bigger is better. Bigger anchors have more strength to resist breakage, more surface area to resist pullout, and generally more weight to penetrate the seabed. It is a mistake to choose an anchor that weighs less or stows compactly and risk having an anchor that won’t work when you need it. See our chart inside for size recommendations based upon overall boat length. Anchor Designs:  The majority of anchors fall into one of three categories. First, there are high-penetration, lightweight, pivoting-fluke anchors like those from West Marine, Danforth and Fortress. They have the greatest holding power per pound of any style, based upon the large surface area of the flukes. Second are the more massive, plow-style anchors like the Bruce, Delta, CQR, Spade and Max. They have excellent structural strength, but do not penetrate as deeply into the seabed and/or have less holding power per pound than fluke-style anchors. However, they sometimes tend to set more easily due to increased weight. Finally, there are specialty anchors for specific bottom types with varying amounts of holding power (mushroom, grapnel and Yachtsman). Variations on these traditional designs exist, and new ones seem to be introduced all the time. In general, we have not been impressed by the performance of anchors whose designs fall outside the existing parameters. DO NOT allow yourself to be swayed by marketing hype and advertising gimmicks for the “newest concept in anchoring.”  We see anchors as a critical piece of safety gear to protect your investment in your boat. As a rule, you should not compromise for poor quality, “cheapo” anchors. Be on the lookout for spotty galvanizing, poor welds and other inconsistencies in the metal. We have carefully selected all the anchors we offer, and feel confident that these brands are the finest available. Here’s a brief rundown of each type that we sell, with pros and cons. West Marine Traditional -  Pros: Adequate holding power in sand and mud. Precisely made to original Danforth dimensions for roll stability and dependability, especially stock length and shank-fluke angle.  Cons: More expensive than many poorly made fluke-style anchors. Limited or no holding in thick grass, rocky, or clay bottoms.   West Marine Performance and Danforth Hi-Tensile -  Pros: Excellent holding power and resistance to damage. Constructed from heat-treated, high-tensile steel. Lightweight, buries deeply, and has tremendous strength. Precision control of the fluke-shank angle and symmetrical, “T” shaped flukes.  Cons: More expensive due to design and materials. Limited holding power in thick grass, rocky, or clay bottoms.   Fortress -  Pros: Excellent holding power in both sand and mud. Constructed from lightweight aluminum. Can be set for sand bottoms with a 32° fluke angle, or mud with a 45° angle. Can be disassembled for storage.  Cons: Light weight may make sets difficult in current and when underway. Limited or no holding in thick grass, rocky or clay bottoms.   CQR -  Pros: Good multi-bottom anchor - penetrates weeds and grass, hooks coral, penetrates sand and mud. Very strong construction.  Great reputation among cruising sailors.  Cons: Expensive. Hard to stow except on a roller. Limited holding power in mud.   Delta -  Pros: Very strong construction. Free-fall design for easy deployment from anchor rollers. One piece design, with narrow shank cross-section.  Cons: Expensive materials and construction result in higher price. Limited holding power in mud.   Bruce and Claw -  Pros: Quickly sets in most seabeds. High-strength design. Good holding power, veers well due to its roll-stabilized design. Acts like a grapnel in rock and coral.  Cons: Difficult to stow unless in rollers or chocks. Limited holding power in mud.   Spade -  Pros: Relatively new anchor design which is best described as a concave Delta. Has received rave reviews from cruisers around the world as a high-holding power anchor with excellent strength and versatility. Available in galvanized steel, stainless steel and aluminum construction.  Cons: Difficult get in the U.S. since it is manufactured in Tunisia (but we have it). Somewhat expensive, especially if the shipping is paid for by the customer.  Select an anchor based upon its ability to hold in the expected bottom conditions. Remember that physical size, not weight, is usually the best indicator of holding ability. For inland boaters, a single anchor of strong design and adequate size is appropriate. For coastal and offshore cruisers, two anchors of contrasting design (fluke and plow) are recommended for increased security and holding in different sea beds. Assessing Bottom Conditions: Anchors need to develop enough resistance in the seabed to withstand the environmental forces on the boat—the wind and the waves. An anchor’s ability to develop resistance is entirely dependent on its ability to engage and penetrate the seabed. We have participated in several anchor tests, and despite varying results, there always seems to be one undeniable conclusion: the selection of a suitable bottom for anchoring is a much more critical factor than the design of the anchor. So how do you choose the right anchor design? You must take expected bottom conditions into account. Here is an analysis of potential options, based on the seabed. Sand: Fine-grained sand is relatively easy for anchors to penetrate and offers consistently high holding power and repeatable results. Most anchors will hold the greatest tension in hard sand. Best in sand are the West Marine and Fortress anchors.   Mud: Mud has low sheer strength, and requires anchor designs with a broader shank-fluke angle and greater fluke area. This allows the anchor to penetrate deeply to where the mud has greater sheer strength, and also presents more surface area in the direction of pull. Mud is frequently only a thin layer over some other material, so anchors that can penetrate through the mud to the underlying material will hold more. Fortress anchors have superior holding power in mud, because they can be converted to a broad fluke angle.  Rock and coral: Holding power is more dependent on where you happen to drop the hook, than on the type of anchor you have. Plow-shaped or grapnel-type anchors, with high structural strength to sustain the high point loads generally work the best. These include the Bruce, CQR, Delta, or Yachtsman. Shale, clay and grassy bottoms: Tough bottoms for all anchor designs. The weight of the anchor, more than its design, may be the most important factor in penetration and holding power. CQR and Delta anchors, as well as Yachtsman anchors, are thought to be good due to their ability to penetrate the vegetation. However, these conditions have a high probability of false setting, due to the anchor catching on roots and protrusions, rather than something solid. Anchor Rode Choices: The anchor rode on a pleasure boat generally consists of three strand nylon line with a short length of galvanized chain at the anchor end. Nylon is used because of its elasticity. Its stretch reduces the peak load which your boat places on your anchor (and vice-versa). Galvanized chain is used between the anchor and the nylon line for abrasion resistance, and to keep the pull on the anchor shank more parallel to the seabed. So how do you choose the appropriate components for your boat? We think the world can be divided into four groups. Weekend boaters in inland and coastal areas may carry an anchor simply for use as a “lunch hook” or for unlikely emergency situations. For such applications you can use an all-rope anchor rode. We recommend that you use 1/8" inch of anchor line diameter for every 9' of boat length (every 8' for high-windage boats). All-rope rodes minimize the total amount of weight in the anchor system, but are not recommended for extended anchoring conditions. Most boaters, regardless of location, should supplement nylon line with a small length of galvanized chain at the anchor end of the rode. This helps the rode lie on the bottom, and adds abrasion resistance. We recommend about one-half to one full boat length of galvanized Proof Coil chain, whose diameter is half that of the nylon line (1/2" line = 1/4" chain). To connect the two components, place an eye splice and thimble in the line and use a galvanized anchor shackle which is one size larger than the chain (1/4" chain = 5/16" shackle), or use a rope-to-chain splice. A rope-to chain splice allows the rode to self-stow when used on windlasses with rope-chain gypsies. Abrasive bottom conditions, especially coral, require more chain to protect the soft nylon rode from the bottom. In general, chain has greater longevity than nylon line, so longer lengths of chain (from one to three boat lengths) will help extend the life of the rode. Remember that chain weighs one to 2lb. per foot, so adding more chain dramatically increases the weight of the rode, as well as the strain on your back. Large diameter chain will be much heavier, and will lie on the bottom in higher winds, but may present some penetration resistance in hard sand.  Long-distance cruising boats and boats with larger windlasses generally use all-chain rode. This reduces the need for scope because chain is very heavy and lies easily on the bottom. Chain is also “self-stowing” when weighing anchor. It is important to consider, though, that a windlass and all chain rode may add 250lb. to the bow of your boat and adversely affect its performance. For boaters who want to save weight, yet still need a lot of tensile strength, we recommend Hi-Test chain, which is about 50% stronger than similar-sized Proof Coil. A Note on Scope: Scope is the ratio of anchor line paid out to water depth plus freeboard. Anchors hold the most when the pull on their shanks is parallel to the seabed. More line paid out also increases shock absorption by the anchor line. Anchoring experts continue to recommend 7:1 scope when possible, although cruisers might laugh at the idea of paying out 7:1 scope due to limited swinging room in crowded anchorages. Shorter scope must be compensated for by using larger anchors or more chain to lower the angle of pull.   General Observations: Despite claims to the contrary, no single anchor design is best in all conditions. A particular anchor design will generally perform well in one or more bottom conditions, but will be less effective in others. Boaters voyaging to areas where there is a specific type of bottom must carry an anchor(s) suitable for that bottom.  For all but very small boats, we recommend that all boats carry at least two anchors, for the following reasons: • You’ll have another if one anchor is lost. • Different anchor types will handle different conditions. • You can anchor bow and stern in tight anchorages.  Anchors are safety gear. Don’t skimp and buy cheap, poorly engineered and constructed junk. Look for quality construction features (beefy components, strong materials, strong welds, good galvanizing) when choosing an anchor. When in doubt, select the larger size. For an extra $50 or $100, the next larger size will simply hold better. Size should be a consideration when it comes to anchor storage, but safety should not be compromised to save space. The Effect of Wind: Larger boats present greater resistance to the wind, which in turn pulls harder on the anchor and rode. Sizing anchors based upon conservative wind velocities is foolish because you cannot run out and buy "the next size up” when the wind pipes up. Since wind determines the overall force on an anchor system, we recommend sizing your anchor to withstand heavy weather.  Inspect your entire anchor system frequently for chafe, loose shackles, and bent flukes. The system is only as reliable as its weakest component. Store at least one anchor so that it can always be used immediately. Even the strongest anchor won’t do you any good if you can’t deploy it. Quickly deploying even a small anchor can keep you from going further aground.   West Marine's Anchor Selection Chart Got a question about boating safety? Post your question in one of our Boating Forums! Got a boating safety tip to share with others? Share it in one of our Boating Forums or submit an article about it and have it published right here on BOATOhio.com! Back to the top... Back to the Boating Safety Index...