Choosing The Right Boat Anchor: A Comprehensive Guide

Choosing the right boat anchor is critical for safety and performance. The best anchor depends on several factors, including the size and type of boat, the seabed composition, and wind conditions. Boat anchors come in various types, such as fluke, plow, mushroom, and claw anchors, each with its own advantages and disadvantages depending on the anchoring conditions. It is recommended to consider carrying multiple anchors of different types to suit different seabeds and conditions. When selecting an anchor, it is crucial to prioritize holding power over weight, as this determines the anchor's ability to withstand pull force and keep the boat in place.

Holding power vs. weight

Holding power is the most important factor when choosing an anchor. While weight does play a role, it is more important that the anchor penetrates the surface of the seabed and creates enough resistance to withstand the force of the wind and waves.

The weight of an anchor is important when choosing one for your boat, but it is not the only factor to consider. Bigger is usually better when it comes to anchor weight, as more weight means more holding power. However, this is not always the case. For example, some anchors that weigh only 5 lbs can hold over 1,000 lbs. The weight of the anchor is important, but what you're really looking for is holding power, which may have little relation to the anchor's size and weight.

The holding power of modern anchors varies between 10 and 200 times the anchor's weight. This means that some anchors can generate more than twice their weight in holding power. As a general rule, a holding power of 90 lbs is sufficient for safely anchoring a 20' boat in winds up to 20 mph. For a 25' boat in the same wind speed, a holding power of 125 lbs is adequate.

The type of seabed you are boating on will also determine how much weight you need in an anchor. For example, rocky bottoms require anchors to snag on protrusions and hold precariously, rather than dig in. In this case, the weight of the anchor is less important than its design. Anchors with a roll bar, such as the Rocna and Manson Supreme, can penetrate the seabed more easily and create more holding power.

The size of your boat will also guide you in choosing the weight of your anchor. A good rule of thumb is to calculate one pound of anchor weight for every foot of boat length. However, this is not always accurate, as the efficiency of an anchor depends on its shape as well as the seabed and water conditions. For example, a 22' aluminium Jon boat may need a much smaller anchor than a 22' fibreglass cruiser, depending on the seabed and water conditions.

It is recommended that you carry the largest anchor that will fit on your boat. If you are anchoring in very deep water, using an anchor one size up could be beneficial, as it will allow you to set the anchor faster and with less line.

Bottom conditions

For example, if you are anchoring in sand, a Danforth or fluke-style anchor is a good choice. This type of anchor is designed to dig into hard sand and soft bottoms, and its flukes can bury themselves in the sand. However, they are not suitable for rocky riverbeds as they cannot dig in and hold. For rocky bottoms, a grapnel anchor is a better option as its shape allows the flukes to hook onto rocks and hold strong.

If you are anchoring in mud, you will need an anchor with a broader shank/fluke angle and greater fluke area so that it can penetrate deeply and reach a harder secondary bottom material. A plough or scoop anchor is a good choice for mud, as well as for clay and sandy bottoms. These anchors do not have projecting flukes that can foul easily, but their curved shanks make them more awkward to stow.

Mushroom anchors are best for soft, muddy bottoms. Their small size makes them easy to stow, and they are a popular choice for smaller boats and personal watercraft.

If you are anchoring in an area with grass, weeds, or vegetation, the weight of the anchor is often more important than its design. A Navy anchor is a good choice for these conditions as its long stock and distinct flukes can take hold of a crevice.

For shale or clay bottoms, the Claw, CQR, Delta, Rocna, and Supreme anchors are thought to be good due to their ability to penetrate vegetation. However, these conditions can pose a challenge to any type of anchor, and there is a high probability of false setting due to the anchor catching on roots and protrusions.

Anchor weight

The weight of an anchor is an important factor in its effectiveness. The general rule is: the bigger the boat, the heavier the anchor. However, this is not always the case, as the weight of the anchor is less important than its holding power.

The weight of an anchor is important in determining its holding power, which is the amount of pull force the anchor can withstand to hold the boat in place. The holding power of an anchor is dependent on its ability to penetrate the seabed and the suction created by the bottom material, as well as the weight of the material above the anchor. For example, in rocky bottoms, anchors snag on protrusions rather than digging in, so the weight of the anchor is less important than its structural strength.

The weight of an anchor is also important in determining how much anchor rode (the line connecting the anchor to the boat) is needed. A good rule of thumb is to use one foot of rode for each foot of boat length. However, if you plan on anchoring in deep water, you will need more line.

When choosing the weight of an anchor, it is recommended to consider the following:

• The size and type of your boat
• The conditions you will be boating in (wind speed, current, water depth, etc.)
• The type of seabed you will be anchoring in (sand, mud, rocks, etc.)
• How you use your boat (day trips, overnight trips, offshore, etc.)

For example, a 22' aluminum Jon boat may need a much smaller anchor than a 22' fiberglass cruiser, depending on the seabed and water conditions.

It is generally recommended to carry the largest anchor that will fit on your boat and to have multiple anchors of different weights and styles for different conditions.

Anchor rode

The anchor rode is a critical component of your anchoring setup, connecting the anchor to your boat. It is typically made of rope or chain, or a combination of both. When choosing an anchor rode, there are a few important considerations to keep in mind. Firstly, it is crucial to have sufficient length for your setup. As a starting point, consider having one foot of rode for each foot of the boat's length. However, this may vary depending on the depth of the water and the specific anchoring situation.

For example, in 80 feet of water, you will likely need more than 80 feet of rode. Additionally, using a combination of rope and chain is generally recommended over using just rope or chain. The metal chain, connected to the bottom of the rope closest to the anchor, acts as a weight underwater, keeping the front side of the anchor down and preventing it from bobbing up when waves hit the line. The rope, on the other hand, pulls the chain, allowing the anchor to dig into the floor and set itself.

When anchoring, it is important to have plenty of anchor rode, allowing the anchor to be far out from the boat. This helps the anchor to set itself effectively without interference from the boat bobbing up and down in the waves. For instance, in 10 feet of water with a sandy bottom, you may require 60 to 80 feet of line.

Remember, the rode plays a crucial role in ensuring your anchor holds firmly and keeps your boat secure. By taking into account the specific conditions and following the guidelines above, you can make an informed decision about the type and length of anchor rode that best suits your anchoring needs.

Anchor style

There are several anchor styles to choose from, each with its own advantages and disadvantages depending on the seabed composition, wind conditions, and size of the boat. Here are some of the most popular anchor styles:

Fluke Anchor

The fluke anchor, also known as the Danforth anchor, is a popular choice for smaller boats as it folds flat for easy storage and has excellent holding power relative to its weight. It performs well in hard sand and mud bottoms, but struggles in rocky or grassy surfaces. It is also prone to getting fouled on rocks or the anchor rode. The fluke anchor is typically recommended for boats 30 feet or less in length.

Plow Anchor

The plow anchor, also known as the CQR or Delta anchor, is a versatile option that works well in most bottom conditions except rock. It has a single penetrating point and can often reset itself if the wind or current changes direction. This style is bulkier and more challenging to store than the fluke anchor. It is a common choice for heavier powerboats and cruising sailboats.

Scoop Anchor

The scoop anchor is a variation of the plow anchor, with a broader scoop shape that makes it well-suited for mud, clay, or sandy bottoms. Like the plow anchor, it can be challenging to store due to its shape.

Claw Anchor

The claw anchor, also known as the Bruce anchor, is an all-purpose anchor that performs well in most conditions, including mud, sand, rock, and coral. It has an easy setting and resetting capability but struggles with harder surfaces like clay or heavy grass. The Bruce anchor is a popular choice among recreational boaters in North America.

Mushroom Anchor

The mushroom anchor gets its name from its distinctive shape and is commonly used for small boats, personal watercraft, or permanent mooring buoys. Over time, silt builds up on the mushroom anchor, increasing its holding power. It works best in soft, muddy bottoms but is not recommended as a primary anchor for larger boats.

Grapnel Anchor

The grapnel anchor is designed for rocky bottoms, with flukes that can hook onto objects like rocks. It is compact and foldable, making it suitable for small boats such as kayaks, canoes, and dinghies. While it may not have the same holding power as other anchors, its design and size make it a good secondary or stern anchor.

Frequently asked questions