Anchor a Boat

One of the first things that every sailing enthusiast must learn how to master is the proper technique for anchoring a boat.

The primary job of an anchor is to dig into the seabed and temporarily secure the boat, holding it in a relatively fixed position until the boaters are ready to set sail again.

In addition, anchors provide an important safety measure by way of keeping the boat off the rocks and out of the surf, which can reduce the risk of damage or accidents. Below is a basic guide that will teach you how to properly anchor a boat.

Anchor a Boat

Choose the Anchor According to the Bottom Condition

It is important to have a basic knowledge of what type of bottom you’ll be anchoring into; otherwise, you could run the risk of your anchor not properly set, basically rendering it ineffective.

There are all kinds of different anchors that come in a variety of designs for different bottom conditions, but the real key to successful anchoring depends more on properly selecting an appropriate bottom for anchoring than on the design of the anchor itself.

The following is a quick synopsis of the main seabed types, along with the recommended anchor types to suit each condition.

Anchor type

* Mud – Mud typically has a low level of shear strength, which means that you will need an anchor that has a more expansive fluke area as well as a sharper shank-fluke angle.

This will allow the anchor to achieve a greater level of penetration into the mud, and it provides a broader swath of material for the mud to hold against in order to provide more resistance to the pull.

Quite often mud is simply a layer of material on top of some other type of material, which means that if your anchor can manage to penetrate deep enough to set into the lower layer, it will provide a much firmer hold. One of the best anchors to use in mud is a Fortress anchor due to its adjustable fluke.

* Sand – Sand is definitely one of the most anchor-friendly bottoms due to its consistent holding power and predictable results.

Whenever you have a hard sand bottom, you can expect your anchor to hold with robust tension. Lightweight anchors such as the Fortress or West Marine Traditional, both of which are basically Danforth-style variants, work excellent in sand.

* Rock – In terms of determining holding power, the type of anchor you’re working with is secondary to the location where you’ll be dropping the hook.

Grapnel-style or plow-shaped anchors work well for this purpose, as they offer reliable structural strength. While Delta, Bruce or CQR anchors work well, the old-school Fisherman anchors can do an adequate job too.

* Shale – Anchor weight is one of the most important factors to securing a good hold when you’re working with this type of bottom.

Delta and CQR anchors are typically capable of penetrating through shale, grassy or clay bottoms, but be aware that false settings often occur due to the convoluted shapes and protrusions that are often found on this type of surface.

Choose the Right Equipment

Anchor equipment

* Anchor Size – As you can see just from the above discussion about the various seabed types, your best bet is to utilize several different anchors on your boat, each of a different size or weight.

Your primary anchor should be used for general purposes, such as fishing, etc., while you can use a smaller anchor for temporary deployments and short breaks.

You should also keep a larger storm anchor in case you encounter some particularly rough weather, or if you need to make an overnight stop.

In addition, consider keeping a heavy backup anchor on hand in case one of your anchors gets lost (which does happen), or for situations where using two anchors would be recommended.

Your best bet is to follow the recommendations of your boat’s manufacturer, but if you’re carrying a particularly large amount of weight on your boat, that should definitely factor into any decisions regarding anchor size.

If you’re not quite sure, it’s always better to err on the side of caution by purchasing a larger anchor; after all, for most cruising boats, you can never have too much stability, only not enough.

* Anchor Rode – Nylon ropes (known as anchor rodes) are commonly in use today to attach anchors to boats.

The elasticity of nylon is useful for responding to sudden changes in current or wind direction, and they’re fairly easy to manipulate and deploy.

Most anchor rodes feature a three-stranded nylon composition, and they’re fairly resistant to snagging or tearing on objects on the seabed, but they can get difficult to work with once they become stiffened by salt.

* Anchor Chain – Galvanized anchor chains are incomparably strong and they can send the anchor to the bottom quite quickly, but they are definitely more difficult to work with due to their weight.

Top choices that are commonly in use include Hi-test chain (strong yet light), proof coil (features a “G3” imprint on each link) and BBB (smaller links but exceptionally strong).

* It should be noted that many sailors use a combination of rope and chain, which requires extra shackle joints in order to keep each length adequately fastened.

Choose the Spot to Anchor

Spot to anchor

* Depth charts definitely come in handy for this purpose, but don’t forget to use your eyesight as well! Try to avoid any areas where strong currents are present (especially for an overnight stop), and try to select a location that is best suited for your anchor type.

* Wherever you choose to anchor, you have to be sure that you have an adequate swing radius in all directions, in case the wind or current changes.

Take a measurement of the depth of your potential anchoring spot, and then multiply that number by 7; this will give you a rough estimate of how far you can expect your boat to drift from the spot where your anchor is set.

Once you have confirmed that you will have adequate clearance on all sides, you can then safely drop your anchor.

* Check tide and weather information, and be aware of the timing of both the high and low tides to be on the safe side.

Keep an eye on the weather forecast for potentially threatening conditions, such as high winds or potential storms.

How Much Rope You’ll Need

Anchor rope

* A common newbie mistake is not including the bow in your depth measurements. To get an accurate picture of how much rope you’ll need, add the height of the bow above the water to the total water depth. If the water depth is 12 feet and your bow is 5 feet above the water’s surface, your total depth will be 17 feet.

* From this total depth measurement, you can determine the scope, which is the ratio of how much anchor line you’ll need in relation to the total depth.

Most experts recommend a scope of at least 7:1 for nylon rope rode and 5:1 for an anchor chain. In our above example, if you were using a nylon rope rode, you would need to let out 119 total feet of line (7 x 17 feet). In stormy conditions, use a scope of 10:1 for additional stability.

* Once you have determined your scope measurement, cleat the anchor line at that length. Make sure to tie a strong knot in order to achieve a firm and robust cleat hitch.

How to Drop Anchor

* Make sure to slowly and deliberately lower the anchor over the bow, and give the line only enough play to tightly control the anchor’s direction until it safely hits the bottom.

Although it’s a popular trope in movies, throwing your anchor overboard in real life will most of the time cause a tangled mess in your line.

* Gradually let out the line, 1/3 at a time, making sure that the boat is straightening out as you allow the line to straighten out as well.

If the boat doesn’t seem to be straightening out at all, more than likely your anchor is drifting and hasn’t set. Try again, this time picking a comparable spot if possible.

* If the anchor has been properly set, the boat should straighten out, which should further set the anchor into the seabed.

Once this happens, firmly tie your anchor rode around a bow cleat. At this point, it’s a good idea to tug on the line to double-check and make sure that the anchor has indeed been set.

* “Snub” the anchor, which means using your engine to give it a final hard set.

The helmsman should put the boat in reverse until the rode is pulled taut; once this is done, turn off the engine and check to make sure that the anchor wasn’t pulled free.

Resetting

Reset anchor

* If wind direction or current is inconsistent, it can cause the boat to pull in different directions, which can sometimes dislodge the anchor.

If your Chartplotter features an anchor alert, set it to notify you of any abnormal boat swings that seem too far from the place where the anchor was set.

* Set water depth alerts on your depth sounder, so that if your boat begins to drift into significantly shallower or deeper water (a sign that the anchor has come loose), you’ll know about it.

* Identify landmarks that can give you a good sense of where you first set anchor. If you notice that the boat has drifted too far from these landmarks, it’s probably time to reset your anchor.

* Set alerts on your autopilot or electric compass to notify you of any radical changes in the boat’s heading. Reset your anchor if need be.

Why Use Two Anchors?

Sometimes you’ll be forced to work within confined anchorages, which means you’ll have to keep a closer eye on your boat’s swing radius.

Try dropping one anchor offshore and the other one closer to the beach, which will offer a more firm position for your boat. Another recommendation is to drop one anchor into the current or wind, and another one 180 degrees away.

After that, pull both lines to the bow, which will create a nice, tight arc within which the boat can swing around without possibly resetting when the current or wind changes.

In addition, as mentioned earlier, two anchors are useful in case one gets lost, and with more than one anchor, you have the flexibility select the most appropriate anchor type for the conditions you’re working with.

Conclusion

There is no substitute for experience, so if you get an opportunity to learn how to anchor a boat from a seasoned sailor, make sure to take advantage of it. Keep the above tips in mind as well, and be sure to assimilate and practice them until they become second nature.

Do you know how to anchor a boat? If so, you are welcome to share your experience in the comments below.

8 COMMENTS

  1. Daniella,
    I love this post mainly because when most folks take to the water on any sort of vessel the anchor is probably one of the least thought about items on board.

    I will admit to never have given any thought to the bottom surface that I would try to be anchoring to, mainly because you can rarely see the bottom.

    I also greatly appreciate the thought process of making the anchor as important a tool as it really is, great job and I really have enjoyed the rest of your site as well,
    Gary

    • Hi Gary,

      For anyone going sailing, anchoring is on of the most important thing not to neglect. A poor anchoring can turn you sailing holiday into an embarrassing situation.

      I am glad you like my article and wish you a wonderfull day!

  2. I didn’t know that there were different anchor designs for different bottom types. But now it comes to a logical sense.

    The way you explain all the formation types and different anchor types suitable to them are really interesting to read.
    Good work and impressive article. I haven’t got bored while reading it.

    • Hi Tyler,

      Yes, there are so many different techniques as well!

      I am glad that you enjoyed my article and that you didn’t get bored:)

      Thank you for the comment, I truly appreciate!

      Have a wonderful day!

  3. Technique apart, I think some people who love to sail ignore how important to anchor and use with their brute force.

    What I’m saying is that it’s not conducted properly. This, I think, could damage both the boat and the person as a result.

    I’ve never anchored a boat so there’s not much to say in all honesty. Still, thanks for sharing the tips. Interesting and knowledgable.

    • Hi Tar,

      People don’t ignore at all how important anchoring is. They know that this is a very significant part of sailing. This article is more for beginner and for who want to learn a bit of theory before practicing on a real boat:)

      Thank you very much for the comment and wish you a lovely day!

  4. I have to admit my ignorance here. Even though I am fairly experienced at boating, more so in lakes than in the ocean, I had no idea that there were different anchor designs to help you adjust to different types of bottoms.

    Very informative post. I definitely learned something today that will make me a better prepared boater in the future.

    • Hi Alec

      Indeed, there are difference types of bottoms, that’s why it is very important to choose the correct anchor according to it. There is a huge different between rocky, sandy, weedy, mud, etc.. So, make the right choice when you buy it!

      I am glad you’ve found the article helpful:)

      Thank you for the comment and wish you a wonderful day!

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