How To Anchor A Boat

To the uninitiated, anchoring a boat is a pretty straightforward task. You drop the anchor over the side, and bam, you are anchored. How much more could there be to it?

Contrary to popular belief, anchoring a boat is a bit more complicated than it may seem. Just ask the hundreds of boat owners every year who accidentally chuck their anchor into the water without connecting it to the boat. But there’s a lot more involved than just tying your anchor to your boat.

Here’s a guide to anchoring your boat safely and securely.

Boat Anchor Basics

Anchors work by clinging to the seabed, which prevents a boat from drifting. This can keep your boat in place when you are fishing or keep you in the same spot for swimming. It is also essential for safety. For example, if you want to spend the night on the water, you don’t want to drift into rocks or float out to sea!

How an anchor attaches will depend on the nature of the seabed. If the bed is muddy or sandy, a broad, plow-style anchor can dig in and provide suction. For rocky bottoms, hook or grapple-style anchors are best since they can grab onto the rocks. Vegetation is perhaps the most challenging type of seabed, but a heavier anchor is most suitable since it can effectively penetrate the roots and leaves to reach the bottom.

Anchoring A Boat: Step By Step

Step 1: Check The Depth And Determine Your Scope

Before you drop your anchor, you will need to know how much line to release, depending on how deep your water is. So, the first thing you will need to do is measure the depth. If you don’t already have a depth finder, now is an excellent time to buy one. Otherwise, you will need to guesstimate.

Now, multiply that depth by the scope of the anchor. In almost all cases, this is going to be a 7:1 ratio. The scope is simply the ratio of the depth to the length of the anchor line. For example, for 10 feet of water and a standard 7:1 scope, you would need to let out 70 feet of anchor line.

In tighter anchorages, a 7:1 scope may not be possible. In this case, it is possible to tighten the scope to a 4:1 or even a 3:1 ratio. Lower than that, and your anchor won’t have much holding power.

Step 2: Drop The Anchor

Now that you know how much line to let out, it is time to drop your anchor. With the boat at a complete stop, lower the anchor slowly into the water. Many people drop the anchor straight in, but that’s a terrible idea. The line can get bunched up, complicating the entire process. The excess line can also get looped or tangled around rocks and other underwater structures.

Ideally, your boat will drift backward slowly as you lower the anchor. Allow this to happen naturally until the entire line has been released. If there is insufficient wind or current, you can apply a bit of reverse throttle to keep the boat in motion. When dealing with swift winds or currents, you may need to use some forward throttle to slow the boat’s drift.

If performed correctly, the anchor should now be on the bottom, but far out in front of your boat, with the line taut and angled.

Step 3: Set The Anchor

Now that the anchor is on the bottom, it needs to be “set” or fastened to the seabed. To do so, tension must be applied to the anchor line. Tie the line around a cleat, and put the boat in slow reverse. It should pull the line taut, and the boat should rock forward slightly when you let off the throttle.

If the boat does not rock forward, you haven’t set your anchor. You have just dragged it along the bottom. To ensure that the anchor is set, you may need to try a few times. Don’t give up! Otherwise, your boat can drift around freely. You may as well not even drop an anchor in the first place!

Step 4: Keep Watch, And Reset If Necessary

Remaining at anchor is easy when you have consistent wind and current. For instance, if you have anchored in a river, you can essentially remain anchored indefinitely since you will be pulling at the anchor from a consistent direction.

That said, currents, tides, and winds can all change in a hurry. So if your boat drifts in the wrong direction, it can pull the anchor free from its mooring. Thankfully, there are a few ways to avoid this:

  • First, set alerts on your depth finder and chart plotter if you have them. The depth finder can let you know if you are drifting towards — or away from — the shore. The chart plotter will let you know if you have drifted too far in any direction.
  • An electronic compass or autopilot can also be helpful. Many allow you to set an alert if the boat’s heading changes. This can warn you that the boat is starting to drift.
  • Last, keep watch, like a good sailor. When you first anchor, pick a landmark and take a bearing. Then, check that bearing every hour or so. If it changes, you know you are drifting around.

Using Two Anchors

One way to reduce the risk of drifting is to double up and use two anchors. Set one anchor on one side and the other anchor at a 180-degree angle. Because of the need for some slack to set both anchors, you will still drift slightly. However, you will drift in a small area between both anchors.

One thing you should never do is secure an anchor to the stern of your boat. If the line is put under tension, it could pull your stern down in the water and swamp your boat. So always fix your anchor to the prow; never to the stern. This is applicable even if you have two anchors. In that case, attach both of them to the prow.