The Ins and Outs of Boat Anchors: Part 1

Different Types of Anchors

Learn about the different styles of anchors and how to select the right anchor for your motor yacht

Knowing how to anchor your boat when necessary is an essential boating skill. In part one of our two-part post on anchoring, we share an introduction to selecting the right anchor for your boat.

Anchoring Your Boat

Anchoring your boat refers to securing it in place in the open sea for hours, days, or months at a time without the use of a dock or a moor. (See our guide to understanding the differences between anchoring, docking, and mooring). There are many instances when you might need to anchor a boat, including:

Spending the night at sea
During stormy weather
Taking a fishing or swimming break
Getting fueled up
Retiring the boat for the season
Relaxing to enjoy the scenery

How Many Anchors Do You Need?

Anchoring your boat involves dropping a large heavy object that is attached to your boat into the water, where it latches itself to the seabed with hooks and suction to keep the boat in place. You can anchor your boat anywhere you’re legally allowed to if you have an anchor cable, known as an anchor rode, that’s long enough (multiply the depth of your desired location – from the top of your bow to the bottom of the seabed – by 7, or by 5 if you have a heavier, all-chain rode to determine the scope).

Most luxury motor yachts come with built-in anchoring systems located at the bow and concealed from view, which takes the guesswork out of which size and weight of anchor is best for your vessel, but if you’ll be anchoring in rough seas and/or varying types of sea beds, we recommend carrying an additional anchor or two of varying styles and sizes.

For example, your boat’s main anchor is a great, all-purpose anchor for extended periods. However, if you’ll be making frequent stops and anchoring often, an anchor one or two sizes smaller that’s easy to deploy and pull up would be considered an asset.

Likewise, a storm anchor one or two sizes larger would provide more peace of mind during rough weather or for overnight stops. In addition, it’s always good to have at least one heavy backup in case you lose an anchor, or for situations where it’s wise to use two anchors.

Choosing the right anchor

There are several different types of boating anchors available. Each one is designed for various types of sea beds (i.e., mud, grass, sand, coral, or rock). The type of seabed you’re navigating will determine which anchor is most suitable to use. For motor yachts in the Pacific Northwest, a fluke/Danforth anchor is considered a general-purpose anchor. Carrying both a fluke anchor and a scoop style anchor is recommended.

Fluke Anchors

The modern fluke anchor, also called the Lightweight or Danforth, works in both soft mud and hard sand. Once made out of iron, today’s fluke anchors are aluminum, lightweight and consist of two flat, pointed, pivoting flukes that extend at a 30º angle from the anchor rod. Fluke anchors stow flat and have an excellent holding-power-to-weight ratio. Fluke anchors are those iconic-looking anchors most recognized by the general population (i.e. non-boaters). They are not suitable for grassy or rocky surfaces.

Plow and Scoop Anchors

Plow or scoop anchors are single point anchors that are good for grass, mud, and sand. Similar to fluke anchors, both plow and scoop anchors are heavier and have a plow-shaped wedge attached by a swivel to the shaft.

Mushroom Anchors

Shaped like an upside-down mushroom, mushroom anchors don’t have any way of gripping the seabed; rather, they are heavy and burrow under sediment, which is where their holding power comes from. Mushroom anchors should only be used for small boats like inflatable boats, rowboats, and canoes in heavily weeded areas for short stops only.

Specialized Anchors

Additional anchors on the market include the Grapnel, Herreshoff anchors, Delta, and Claw:

Grapnel: a shank with four or more tines small enough to hook into rocky bottoms. Best used in rocky bottoms.
Herreshoff: has small diamond shaped flukes or palms and can be stowed in 3 pieces.
Delta: a plow anchor with a rigid, arched shank that is self-launching.
Admiralty or Fisherman Anchor: the classic anchor design that consists of a central shank with a ring or shackle for attaching the rode.
Bruce or claw anchor: a claw-shaped anchor that is a variation of the plow design intended to have more staying power. Best used in rocky bottoms.

If you’re unsure of what style of anchor is best for your boat, always consult with a boating expert. One of our boating experts at Van Isle Marina will be happy to answer your questions.

Anchor Weight

The size of anchor you’ll need for your vessel will be specified by the boat’s manufacturer. Note that for larger boats, a working anchor and a storm anchor are recommended, with the storm anchor being twice as heavy as the working anchor. For 30’ boats, a working anchor weight of 700 lbs is recommended, and for 60’ boats, that number jumps to 2,000 lbs for the working anchor.

We recommend using a larger anchor than specified if there is an unusual amount of weight being carried on your boat. The physical size of the anchor and its type is more important than its weight, but always go for a larger anchor when in doubt.

Anchor Quality: Although they might not seem like it, anchors are an important piece of safety equipment – always buy high-quality anchors. If you are buying a pre-owned anchor, inspect it for rust, poor welding lines, and other inconsistencies in the metal.

Deck Cleats and Rollers: You also need to have the right type of deck cleats or anchor rollers for your anchors. If you may have a bow roller mounted on your boat already, just know that each roller is only suitable for specific types of anchors. If you don’t have an anchor housing on your boat already, make sure you have strong, sturdy deck cleats for tying the anchor to.

Anchor Chain or Rope?

With your anchor selection made, it’s time to pick the anchor line you’ll attach your anchor to. This line is called the anchor rode, and is typically metal chain, nylon rope, or a combination of the two.

Metal Chain is more expensive but requires less replacement over the years. It also helps to drop the anchor more quickly.

Nylon is strong, easy to manipulate, and relatively cheap to use. It also works well during sudden wind and current changes. However, it can snag or tear more easily and need to be replaced more often than chain.

Many boaters opt for using a combination of both materials and are more concerned with having the rode be of sufficient diameter. For example, aim for nylon rope should be 3/16″ (4.8mm) in diameter for a vessel under 10′ (3m) in length and 3/8″ (9.5mm) for a vessel under 20′ (6m). Increase the diameter by an additional eighth of an inch for each additional 10 feet of your vessel length.

When you buy a boat or yacht through Van Isle Marina, our boating experts will help familiarize you with your yacht’s anchoring system, so you feel confident you are prepared for anything when out on the water.

Give us a call or stop by to learn more about how we can help you develop your boating skills.

Anchor Types – Part 1