The Ultimate Guide To Securing Your Boat Anchor

Anchoring your boat is an important skill to master for any sailor. It's essential to know how to put a chain and rope on a boat anchor to ensure your boat is secure and safe. The process involves selecting the right materials, such as a reliable anchor, a strong rope, and a durable chain, as well as understanding the science behind anchoring to ensure your boat doesn't drift. The weight of the chain, the length of the rope, and the technique used to connect them all play a crucial role in keeping your boat firmly in place, even in rough conditions.

Choosing the right type and size of boat anchor

Type of Boat

A tall sportfishing boat or power cruiser that can catch a lot of wind will need heavier gear than a low-profile bass boat. Boats used for long-distance cruising may need to anchor in rough weather and on a variety of bottoms, so they will need heavier gear and several different types of anchors.

Bottom Conditions

The type of anchor you choose will depend on the bottom conditions where you'll be boating. For example, Danforth or fluke-style anchors are a good choice for smaller boats because they have great holding power for their weight, and they fold flat for easy storage. However, they are less effective in deep mud or grassy bottoms.

Plow anchors are a good choice if the anchor is secured on a bow roller. They have a single penetrating point and can be effective in light grass and rocky bottoms.

Claw anchors are similar to plow anchors but have a broader scoop shape that works well in mud, clay, or sandy bottoms. They are also strong enough for rocky bottoms and will reset quickly if the wind changes.

Grapnel anchors are shaped like a grappling hook and are designed to grab onto structure on the bottom, such as rocks or submerged timber, rather than sinking into the bottom. They are available in many sizes, including very small models for jon boats, skiffs, or kayaks.

Mushroom anchors are very large and used for moorings or securing buoys. Small mushroom anchors may be effective in the softest river bottoms but have minimal holding power. They should only be used for personal watercraft, small aluminum fishing boats, or dinghies.

Boat Size

In general, the bigger the anchor, the better. However, anchor weight is not as important as its holding power, or the amount of pull force the anchor can withstand to hold the boat in place. As a rule of thumb, a holding power of 90 pounds is sufficient for safely anchoring a 20' boat in winds up to 20 mph. For a 25' boat in the same wind speed, you'll need a holding power of 125 pounds.

It's recommended to carry the largest anchor that will fit on your boat. If your boat is 22' or less, you have several options, including 7 lb, 10 lb, or 14 lb anchors. For boats 28-34 ft in length, an 18 lb anchor is recommended for winds up to 30 mph. Boats in this size range typically have large anchor lockers or mounted anchors.

If you're boating in extremely deep water, using a longer length of chain can help the anchor set faster and reduce the amount of line needed. In these situations, using an anchor one size up from what's recommended for your boat size can be beneficial.

Chain Type

When choosing a chain for your anchor, avoid vinyl-coated chain (VCC), as it's meant for playgrounds and swingsets and will wear off after one season. Zinc-plated chain, often sold as an "all-purpose chain," is also not recommended for marine environments as it will begin to rust after a month or less. Instead, opt for Hot Dip Galvanized (HDG) chain, which has high corrosion resistance.

By following these guidelines, you can choose the right type and size of boat anchor to keep you safe on the water.

Using a rope to chain splice

To attach a rope to a chain, you can use a rope-to-chain splice. This is a safe, strong, and simple method that can be used even if you're using a windlass, which doesn't allow for a shackle between the rope and chain.

Prepare the Rope: Count back approximately 16-20 "twists" or strands from the end of your rope. Apply tape at that point and then unravel the strands back to this point. You should have 3 strands. Tape the ends of each strand to prevent them from unravelling and label them as 1, 2, and 3.

Thread the Chain: Line up the rope with the end of the chain link. Take strand #2 and pass it through one side of the chain link. Then, pass strands #1 and #3 through the link from the opposite side, staying on the outside of strand #2.

Begin the Splice: Start tucking the strands in an "over 1, under 1" pattern. Tuck strands #1 and #3, then turn everything over and tuck strand #2 – remember to count over 1 and then slide the strand under one.

Continue Tucking: After the first 2 full tucks, ensure that your line is tight against the chain link and that each strand flows smoothly through each tuck. All tucks should go right to left, so keep flipping everything over to avoid confusion. Complete a minimum of 5 full tucks, keeping each one tight without distorting the lay of the line. Maintain the natural twist in each strand as you tuck.

Finish the Splice: Lightly roll the splice back and forth while pressing down to smooth it out. Once you've completed all your tucks, trim off the excess strand. Some people also like to use a butane torch to lightly melt the end of each strand to keep it in place.

Regularly check the splice for any signs of chafe, wear, or unraveling, especially if it's bearing a lot of load or being used in rough conditions.

Alternative Method:

An alternative method is to seize the rope about 16 inches from the end with ordinary whipping twine to prevent further unravelling. Then, unlay the twist to the seized point, taping the ends with electrical tape. Feed 2 strands through heat shrink in one direction and one in the opposite direction. Pull all the strands tight and apply heat to shrink using a high-heat hair dryer. Cut the whipping carefully and continue with an eyesplice. After 3 complete tucks, reduce the tails by 1/3 and melt flat with a hot knife. Continue with 3 more tucks for a nice taper, then cut off the remaining lengths and melt flat.

Selecting the right anchor chain

Material: Hot-Dipped Galvanized vs. Stainless Steel

Hot-dipped galvanised chains are the most prevalent option for motor and sailing yachts due to their corrosion resistance. The process involves hot-dipping the chain in molten zinc, creating a multi-layered, deep-seated fusion that protects against abrasion. While all galvanising will eventually rust, hot-dipped galvanised chains can last for years without seeing a drop of rust.

Stainless steel chains, on the other hand, offer a more pristine appearance and are available in different grades (G3, G4, G6, and G6+). They may also be electro-polished to provide even greater resistance to marine degradation. Stainless steel is generally two to three times more expensive than galvanised chains and not as readily available.

Chain Size and Calibration

The size of the chain depends on various factors, including the length and weight of your boat, windage, displacement, and anticipated cruising plans. The formula for calculating anchor chain size takes into account the length of the vessel, displacement, windage, and weight of the anchor.

There are two main calibrations of anchor chains in Europe: DIN766 and ISO4565. Calibration ensures that each link is the same length and size, which is crucial if you're using a windlass, as the chain must be compatible with the windlass gypsy.

Chain Length

The length of your anchor chain depends on the depth of water you'll be cruising in and your anchoring plans. A traditional rule of thumb is to have a chain that is three times longer than the water depth, ensuring the chain lays flat on the seabed and maximises its holding power. For example, in 10 metres of water, you'd need at least 30 metres of chain.

If you're boating in coastal or global waters without knowing the exact depth, a typical chain length is 80-150 metres. It's also important to consider the size of your anchor locker and the windlass's lifting capacity to ensure it can handle the weight of the chain and anchor.

Grade of Chain

The grade of the chain dictates its linear strength and break load. Grades are comparable between mild and stainless steel, with stainless steel usually denoted by a simple 'G' prefix (e.g., G4 is equivalent to Grade 40). For galvanised chains, Grade 40 and Grade 70 are commonly used, while stainless steel chains are available in G4, G6, and G6+.

It's worth noting that while chain failure is rare, it's always recommended to use a manufacturer break load-rated solution to prevent potential disasters during severe weather.

Manufacturer and Quality

When choosing a manufacturer, opt for a recognised brand with a reputation for quality and reliability. While price can be a factor, it's essential to prioritise the galvanising quality and longevity of the chain over cost. Read reviews, consult experts, and ensure the supplier can provide a test certificate to guarantee the chain's quality and compliance with safety standards.

In summary, selecting the right anchor chain involves considering the material, size, calibration, length, grade, and manufacturer. By taking these factors into account, you can ensure your boat's anchoring system is safe and reliable.

Understanding the importance of anchor rode

The anchor rode is a critical component of any anchoring system, connecting the anchor to the boat. It typically consists of a combination of chain and rope, with the chain situated at the anchor end. The importance of the anchor rode lies in its ability to withstand the forces acting on the anchor and maintain a secure connection between the anchor and the boat.

The primary purpose of the anchor rode is to absorb shock loads and provide elasticity, preventing the anchor from dislodging or breaking under stress. Nylon is the material of choice for anchor rodes due to its elasticity, strength, and ability to absorb shock loads. It is flexible, strong, and lightweight, making it ideal for anchoring. Nylon's elasticity also helps to mitigate peak loads on the anchor and boat, ensuring a more secure connection.

Another advantage of using both chain and rope in the anchor rode is to protect the nylon rode from abrasion and wearing away. The chain, being heavier, lies on the bottom and holds the rode in place, ensuring that the pull on the anchor is horizontal. This reduces the chances of the anchor unsetting or breaking free. The weight of the chain also helps to achieve the optimal angle between the rode and the seabed, further stabilising the anchor.

The length of the anchor rode is an important consideration. The general rule of thumb is to have approximately 1 foot of chain for every 1 foot of boat length. However, in extreme conditions or extended periods of anchoring, it is recommended to have 1 foot of chain for every 6 feet of rope to achieve an optimal angle between the rode and the seabed. The amount of anchor chain required can also depend on factors such as boat length, weight, boating locations, and water depth.

In summary, the anchor rode plays a vital role in the anchoring system by providing elasticity, absorbing shock loads, and protecting the nylon rode from abrasion. The combination of chain and rope ensures a secure and stable connection between the anchor and the boat, even in challenging conditions. By understanding the importance of the anchor rode and selecting the appropriate materials and lengths, boaters can ensure a safe and effective anchoring experience.

Attaching the anchor to the chain

Selecting the Right Materials

The first step is to choose the appropriate materials for your anchoring system. The two main options are galvanised or stainless steel. While it is generally recommended to avoid contact between dissimilar metals to prevent corrosion, using stainless steel connections with galvanised anchor systems is common and can be managed with proper precautions. If you have a stainless steel anchor and chain, use stainless steel fittings to join them together. If you have a galvanised system, galvanised shackles are typically the best choice.

Correct Alignment and Load Distribution

When attaching the anchor to the chain, ensure proper alignment of the load-bearing surfaces. Match the length and shape of the bearing surfaces as closely as possible to distribute the load evenly. For example, use a round pin that fits snugly into a round hole, with both parts being the same length. Avoid pinpoint loads, as they can compromise the integrity of the connection.

Providing Articulation and Allowing Rotation

The connection between the anchor and the chain should be able to withstand forces from different directions. The wind may shift or the tidal set may reverse, causing an "awkward" force on the anchor shank and the connection. Additionally, the anchor may need to rotate as it approaches the bow roller during retrieval. Therefore, consider using an anchor swivel connector or a connector designed to twist or flip the anchor, ensuring it docks correctly into the stem head fitting.

Strength and Quality Considerations

Always use components with a manufacturer-minimum break load rating to ensure the overall strength of the anchoring system. The working life of each part will depend on the quality of the base metal and the finish. For steel, use a minimum grade of 40, treated with hot-dip galvanising. Electroplating is not suitable for a marine environment. For stainless steel, use a minimum grade of 3 marine quality A316. Additionally, consider using shackles with flush-fitting pins to prevent snagging or jamming in the stem head roller.

Attaching the Chain to the Anchor

Now, let's get into the step-by-step process of attaching the chain to the anchor:

• Select the appropriate shackle size. Use shackles one size larger than your chain. For example, if you have a 1/4" chain, choose a 5/16" shackle.
• Connect the anchor to the chain using the shackle. Pass the pin of the shackle through the designated hole in the anchor and the corresponding link in the chain.
• Secure the pin in place. Some shackles have a protruding head with a hole drilled through it for tightening and securing the pin. Others may have a flush-fitting pin.
• Test the connection. Ensure that the shackle is properly aligned and provides sufficient articulation for the anchor.
• Add a swivel or connector if needed. This will allow the anchor to rotate and twist, facilitating easy retrieval and correct docking.
• Consider using a chain repair link (Maillon Rapide) for a streamlined attachment. This option provides a smooth load-bearing surface but may require filing the thread to fit through a calibrated chain, and a thread-locking compound is necessary.
• Check the connection regularly. Ensure that all components are secure and show no signs of corrosion or wear.

Remember to choose materials and connections that suit your specific boat and anchoring needs. By following these steps and maintaining your equipment, you can feel confident in the security of your boat's anchoring system.

Frequently asked questions