Anchoring Basics: Choosing an Anchor and Setting It

Anchoring Basics: Choosing an Anchor and Setting It

Discover Boating, the consumer program of the National Marine Manufacturers Association (NMMA), calls anchoring a basic seamanship skill every boater should master, even if you rarely plan to anchor. An anchor holds you in a quiet cove for a swim or an overnight stay. It's also essential safety gear. If the engine fails, a well-set anchor keeps wind or current from pushing the boat onto a shoal, rocks or a surf beach. Discover Boating also notes that most new boats don't come with an anchor, so it's one of the first things to buy.

This guide covers choosing the right size and type, the parts of the anchor rig, setting and checking the anchor, getting it back up, the federal anchor-light rule, and the mistakes that sink boats. A seamanship course goes much deeper, and our boater education guide lists where to find one.

Choosing the size

Discover Boating says anchor makers' sizing guidance, usually based on boat length, is a good starting point. Go one size up if:

Bigger is generally better, but what really matters is how well the anchor holds in the bottom, not how much it weighs. Boats that cruise long distances may need several anchors for different bottoms and rough weather.

Anchor types

Type Best for Watch out for
Danforth (fluke) Smaller boats. Folds flat, stows easily, great holding power for its weight in sand and hard mud. Less effective in deep mud, grass or rock. Can pull free if the boat swings and pulls the opposite way.
Plow Heavier boats with a bow roller. Single point, likely to reset itself if the boat swings. Good in light grass and soft bottoms, and can hold in rock once it grips. Bulkier and heavier, doesn't fold. Better on a bow roller than in a locker.
Claw Mud, clay and sand. Strong enough for rock. Resets quickly when the wind shifts. Struggles on very hard bottoms or thick weeds (as all anchors do). Best with a bow roller or windlass.
Grapnel Snagging rocks or submerged timber. Folding tines stow compactly. Small sizes suit jon boats, skiffs and kayaks. Grabs structure rather than digging in. Some have bendable tines to free a snag.
Mushroom Very large ones are used for permanent moorings and buoys. Small ones hold only in the softest river bottoms. Use them only on PWCs, small aluminum boats and dinghies.

The rode

The anchor connects to the boat by the rode. On most family powerboats, that's a length of chain at the anchor end with nylon line from the chain to the boat. Together the anchor and rode are called ground tackle. Discover Boating says to keep it ready to deploy at a moment's notice, since you may need it fast if the engine quits.

Setting the anchor, step by step

  1. Find the depth. Use a depth finder if you have one.
  2. Work out the scope. Scope is the length of rode you let out compared with the water depth. Discover Boating recommends 7:1 (7 feet of rode per foot of depth) when there's room. In 10 feet of water, that's about 70 feet of rode.
  3. Approach into the wind or current. Motor about one scope-length (70 feet in the example) past the spot where you want the boat to end up, and lower the anchor. Don't throw it.
  4. Fall back. Let the wind or current carry you back while you pay out rode, or back down slowly if there's no wind or current.
  5. Cleat it at the bow. Once enough rode is out, secure it to a bow cleat.
  6. Set it. Apply gentle reverse power to dig the anchor in.

Make sure it isn't dragging

Pick two landmarks on shore that line up and watch whether they shift, or set an anchor-drag alarm on your GPS, chart plotter or depth finder. If the wind, current or tide changes and the boat swings over the anchor, it may reset itself. If it doesn't, reset it. Discover Boating stresses staying alert the whole time you're at anchor.

Choose the spot with care. Leave room to swing a full circle at your scope without hitting other boats, docks or the shallows. Stay out of channels and heavy traffic, especially with swimmers aboard. Our kids and dogs guide covers swimming from an anchored boat.

Anchor lights and shapes

The federal Navigation Rules (33 CFR 83.30) cover anchored boats:

Getting the anchor back

Motor slowly toward the anchor while pulling in the rode. When you're directly over it, it should break free. If it's stuck:

The mistake that sinks boats

Never tie the anchor off at the stern, and never try to pull a stuck anchor free with the engine while the rode is on a stern cleat. Discover Boating warns this can pull the stern down far enough for water to pour over the transom and swamp the boat. Always anchor from the bow.

Budgeting

An anchor, chain, rode and, on bigger boats, a windlass are usually bought separately from the boat. Add them to your first-year equipment costs in the True Cost tool.

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