The Ultimate Guide To Anchors And Anchor Chain
You may have seen it already over July 4th weekend: a boater going for his/her ground tackle in a hurry only to be stopped by knots, tangles, or an anchor that is not connected properly.
Embarrassment and inconvenience aside, mismanagement of your anchoring system has the potential to cause serious damage. Besides the obvious use of anchoring up at the sandbar, an anchor also serves as an emergency brake. When you need it, you need it right away, and it must work for you. Failure is a dangerous non-option, so in these two articles we will discuss how to keep you safe and your “e-brake” in working order.
What makes up your anchoring system?
Let’s start with what should be a refresher for most of us: some anchoring system terms. These terms are part of the vocabulary we need for discussing anchors. We will also highlight the components of the anchoring system and share tips and rules of thumb to help with anchoring product selection and best practices.
Chain
The length of galvanized metal links used to connect the anchor to the rode. The most common chain coil is BBB rated with thicker, shorter links that are stronger than standard proof chain. Chain is used for its weight and chafe protection. The chain helps the anchor to set and the rode to lie horizontally.
Line
The long length of nylon rope with an eye splice and thimble which is attached to the anchor chain.
Anchor line comes in three-strand, braided, or 8-plait styles. The three-strand variety is popular with boaters because it absorbs shock better than braided and is less likely to fray or get cut on rocks or jagged bottoms.
Anchor line is available in various diameters and lengths depending on your boat. The larger the boat, the wider and longer the anchor line required. There are many options to consider when picking your anchor rope.
Rode
The anchor line and anchor chain combined.
Anchor Shackle
The metal load-bearing connector between the anchor chain and the anchor.
Choose a high-quality shackle that can withstand stress. Hot dip galvanized metal shackles are the most sturdy and durable.
Swivels
A pivoting metal connector that some boaters install next to the anchor shackle.
Swivels are designed to release the twist in the anchor chain as it comes onboard so it will flake into the locker more easily and be ready to redeploy rapidly. Swivels are a hotly debated topic among boaters due to the potential for catastrophic failure of the swivel under high loads.
Snubber
An additional length of line attached to the anchor chain and deck mooring hardware.
Snubbers help absorb shock while anchored in swells or high-wake areas. This takes strain off the windlass and deck. Snubbers are commonly used on boats deploying all-chain rodes.
Ground Tackle
All anchoring related equipment including the anchor, anchor chain, anchor line, shackles, and connectors.
Scope
The ratio of the length of anchor rode deployed to the vertical distance between the sea floor and the point where your anchor rode comes on board.
Aim for a 5:1 scope ratio minimum, although a 7:1 ratio is preferable given the room. The lower the ratio, the greater the chance your anchor may drag.
Holding power
The amount of pull force an anchor can withstand while remaining set.
Holding power is expressed in pounds and can be measured with a strain gauge. Heaver anchors and anchors with large fluke areas tend to have higher holding power.
Kellet
Metal weight of any kind that is attached at some point along your anchor rode.
This ballast weight is also known as an anchor buddy/rider/chum/angel. The weight of the kellet used depends on the size of the boat. Kellets are a controversial and debated solution designed to help anchors set and avoid dragging as well as to dampen the surge from swells or wake.
Catenary
The curve of the anchor rode between the boat and the anchor.
A low angle of pull on the anchor maintains the catenary curve and provides energy absorption. Due to their weight, chain rodes have good catenary curves in light to medium winds, however in strong winds, the chain goes taut and loses its curve, offering no energy absorption.
Setting The Hook: Things To Consider When Selecting An Anchor
With all the anchoring system components fresh in our minds, it is time to apply them and select the right anchor. Three variables to consider during anchor selection are:
Boat Size
As a rule, your anchor chain should be at least as long as your boat, but no shorter than 10 to 15-feet. Your anchor line length will depend on anchoring depth. If you will be anchoring in deeper water, you will need enough rode to achieve a proper scope ratio. The rule of thumb is to plan 8-feet of line per 1-foot of anchoring depth.
Location
Where you anchor makes a difference. What are the currents, winds, and tides like? Will you be anchoring in protected waters? Select your anchoring equipment based on the type of locations and conditions in which you will be deploying your anchor.
Sea Bottom
Do you have a clean bottom? What does your bottom surface consist of? This determines not only holding power but also what anchor works best for the bottom you are anchoring in. Some anchors like a pivoting-fluke or non-hinged scoop do well in sand while others with broad flukes are best in mud. Consider a plow-shaped or grapnel anchor to dig into rocky bottoms and a heavy anchor for difficult shale, clay, and grass bottoms.
Anchor Types and Uses
Anchors come in six different types, and as we learned, the best anchor for you will depend on your boat, your location, and the sea bottom. Whichever type of anchor you choose, ensure you consult manufacturer guidelines to select an anchor weight that is heavy enough for your boat. The six types of anchors are:
Claw
Three claws help the claw or Bruce anchor dig into most types of bottoms, including rock. Note that you need a heavier anchor for your boat size to get a good set. The lower price of a claw anchor makes it a common choice with recreational boaters.
Danforth/Fluke
Pivoting flukes help this anchor bury itself in soft bottoms with grass or mud. A Danforth, or fluke type of anchor stows flat and is often used in smaller boats where space is at a premium.
Grapnel
The fixed upright flukes of the grapnel dig into many bottom types and offer a better hold than a standard fluke anchor in harder bottoms. A light version of a grapnel anchor can be a good choice for smaller boats.
Mushroom
The rounded bottom of a mushroom anchor simply rests on the seabed, making it best for small craft, canoes, and kayaks in waters with flat, even sea bottoms.
Plow
The sharp point of a plow anchor digs into rocky bottoms or those covered in grass and weeds. Plow anchors may also be called CQRs or wing anchors. They are common on larger boats that are anchoring in varying conditions and types of sea bottoms.
Scoop
The newest anchor type – the scoop – works in many bottom types and has high holding power. Scoop anchors are designed to be easier to set and reset than other anchor types. Scoops are available in Rocna, Spade, or Manson configurations.
Most Common Anchoring Mistakes
Time to learn from others’ mishaps. Watch out for these common errors that boaters make when selecting or deploying their anchoring system:
- Not securing the bitter end of the anchor line – usually seen on smaller day cruisers
- Improperly sized anchor for size of boat or conditions
- Wrong anchor for sea bottom
- Not enough scope
- Not enough chain
The Takeaways
Your boat’s anchoring system is like the emergency brake on a vehicle. When you need it, you can’t afford for it to fail. Set yourself up for anchoring success by outfitting your boat with the proper anchor, rode, and other components for the boat size, boating location, and type of sea bottom you expect to anchor in.
When you get ready to anchor, confirm your anchor line is properly secured to the boat and set with sufficient scope so the anchor won’t drag. Following these basic guidelines will help ensure your time on the water is as safe as possible.