Every boater will spend the majority of their time anchored when out at sea whether they are fishing, swimming or just basking in the sun on the boat. Anchoring helps the boat to not just maintain a still position but keeps it from drifting with the current, the surf or hitting rocks and other boats.
This is why it’s crucial to learn how to anchor a boat in the best way. This guide will teach you all you need to know how to anchor a boat.
What anchors do
Anchors work by digging into the sea bed. This creates suction which in turn causes resistance. The more the boat pulls the anchor, the more it digs down into the sea bed creating more resistance until eventually, the boat stops.
Choosing the right anchorage
This is the first step before dropping down your anchor. You want to make sure that your chosen location is ideal, has sufficient sea depth and has enough space for the length of the boat and the length of the anchor rope. In case of strong winds and the boat starts to circle in the water, the radius should be free from other objects that the boat could bump into.
Ensure there are no rocks, shoals and other boats in the immediate distance. You would be lucky if there are no other boats in the anchorage. However, if you sail by and there are other boats, choose the location and the distance wisely to prevent any accidents.
Choosing the right type of anchor
The right type of boat anchor will depend on the type of sea bed that you will anchor into. Generally, your plotter or GPS will tell you what you need to know about the nature of the sea bed.
Most sea beds will have sand, clay, mud, or grass. The different types of anchors includes fortress, delta, spade, CQR, Lemwar, Bruce and Rocna style blades. While any of these will do in most types of sea beds, they have different features that make them perform better with certain anchor techniques more than others.
A sand sea bed is simple for the anchor to penetrate. What’s more, sand offers good holding capacity. The best type of anchor in this situation is the traditional fortress anchor.
With a mud sea bed, there is lower shear strength. The anchor should have a larger fluke area allowing it to dig deep into the mud and reach where there is greater shear strength. In the majority of cases, the mud-covered sea bed often has different materials underneath such as rocks or sand. A fortress anchor will dig deep into the mud and achieve a secure hold.
Yet another reason why fortress anchors are ideal for muddy sea beads is that they can easily be converted into a broad fluke angle.
Some sea bead comprises of rock and coral. Here the holding power of the anchor will depend on where the anchor lands as well as the type of anchor. A plow anchor that features a high structural strength will generally work the best in coral and rocky sea beds.
As for the grassy or clay bottoms, these are often a challenge for most types of anchor techniques. It is the weight of the anchor itself that counts allowing it to dig deep into the seafloor and get past the soft upper part.
One of the reasons why anchoring in such types of seafloors is such a challenge is because they sometimes cause a false setting. This is where the anchor hooks to root-only to later give. Installing boat underwater lights can help you see the seafloor especially when it’s shallow.
So which type of anchor should you go for?
Well, the best solution for the different types of sea beds is to have all the different types of sailing anchors. Also, ensure that the boat has the right size anchor. It should be compatible with the length, displacement of the boat as well as the hull size.
Selecting the right scope length
The ratio of the depth of the water to the bottom of the boat plus the height of the bow from the water surface compared to the length of the anchor line is known as the scope length. This is an important consideration when anchoring your boat as it will determine just how far the boat drifts when you let down the anchor.
The generally accepted scope length is 7:1 or 8:1. This means that if you are in 15 feet of water, with a bow height of 5 feet, then the anchor line should be 20X7 which is 140feet.
While it is possible to adjust the length of the anchor line, it’s important to keep in mind that the longer the scope the better and sturdier the anchoring. As a simple example, if you had a large boat anchor and more chain, you can opt for a 4:1 scope. Other types of anchors may not be able to get a secure hold and you might need a 10:1 scope.
Another important consideration is when you drop the anchor, the tension will be the same regardless of whether you reduce the scope. This means that it’s possible to set the anchor and then shorten the scope afterward.
When you are choosing the right scope length, you will also need to consider how long you plan to stay. A shorter 5:1 scope can be used if you plan on staying for just a short while a longer 8:1 scope is best when you plan on staying longer. A shorter scope is also ideal during calm days.
Choosing the best rode
There are two main types of rodes—nylon or chain. For light-duty anchor techniques, nylon rode will do just fine. A chain rode is ideal for quick anchoring and the great thing with it is that it doesn’t require much scope.
You can also use a chain and nylon rode. It is a common feature to use the combination of these two as it will help in lowering the angle of pull allowing you to set the anchor and keep it set.
Note that when you are calculating the scope size, make sure to exclude the length of the chain on the end of the anchor as its function is to add extra weight to the anchor. However, you can include it if its more than 6 feet of length.
How to anchor your boat
Now that you know what you need to look for in terms of the type of anchors and the different sea beds, it’s time to learn how to anchor a boat.
The first step is to note where you want your boat to be and with a steady and slow speed go past this spot against the wind or current. Where you will set your anchor will depend on the scope length. Having a good boat speedometer will help you pick the best speed when anchoring.
slowly come to a stop and gradually release your anchor. If you were to quickly drop the anchor, it would form a heap of anchor line and chain on the sea bed. Releasing slowly means that only the required length is used.
Based on the type of sea bed, you may find that the anchor will drag for a distance before it hooks to the seafloor. You can include an extra length to your line to cater for this.
After dropping your anchor and it reaches a scope of 3:1 you can now secure your rode and then move the boat in reverse for the anchor to set correctly.
If you notice that the rode loosens then pulls tight, this means that the anchor is skipping. This also means you will need to reset. On the other hand, if the anchor is set correctly, you can now release more anchor line until it reaches the required scope.
You can now turn off your boat engine.
What if the anchor gets dislodged?
There are four ways you can tell if the anchor becomes dislodged.
First, your anchor alarm on the GPS/chart plotter can be set to give you an alarm in case the boat drifts too far or goes beyond the scope length.
An electronic compass on the boat can also be set to give you an alert if the boat changes the direction significantly.
Thirdly you can set your depth sounders to give you an alarm if there is a significant change in the depth of the sea bed.
Lastly, take note of any prominent features near where you are anchored. In case the boat starts to drift further away from such features or landmarks then you can suspect that the anchor is dislodged.
Using two anchors
Sometimes you might find yourself in a narrow body of water with opposite banks being pretty close. What’s even more challenging is if there is another boat around. How do you anchor your boat in such a situation? Well, you use two anchors.
While there are many ways that you can make use of two anchors to properly hold your boat, the two most common methods include.
Bow and stern anchoring
Here you will drop one anchor close to the beach while the next anchor will be set offshore. This holds the boat securely and prevents it from drifting. A useful trick is to take advantage of the tension in the first anchor and use it to set the second anchor.
Dropping two anchors from the bow.
This type of anchoring will require you to drop the first anchor into the current and wind and then drop the second anchor 1800 away from the first. The boat will not drift further out and can only drift in an arc. Every time the wind changes direction, the boat will be held by an anchor.
Pulling up the anchor
When it’s finally time to leave the area, you will need to pull up the anchor. Turn on the motor and move the boat forward towards the direction of the anchor. All the while pulling up the anchor. It should dislodge easily.
Sometimes the anchor might get stuck. In this case, shorten the scope by moving the boat closer to the anchor. Try pulling the anchor while being directly above it. In case it doesn’t dislodge, tighten the rode and circle the boat until you find the position where it will dislodge. Pull it up as soon as it does.
More tips for anchoring a boat
It is always a good idea to carry an extra anchor not just for double anchoring but also as a back up in case the first one gets lost.
Always have an anchor that can be dropped fast. It doesn’t matter how strong your anchor is. If it will take a long time to drop into the seafloor, then you could hit rocks or crash into the shore by the time the anchor holds.
Make regular maintenance checks on the whole anchor system. Remember that the anchor can only be as strong as the weakest parts so check for bent flukes and loose shackles.
To allow you to tell just how much scope you’ve released, you can add plastic numbers on the nylon rode. These are great for telling you the depth. You can also use that boat deck paint that remained after painting the deck to color intervals of say, 25 feet.
If you are in a tight spot and you find that it is near impossible to let out as much scope as you would like, you can add a weight or sentinel to the anchor line. You can attach the weight using shackles.
Anchoring is best done when you have someone with you to help out. You can even come up with your hand signals to communicate from different sides of the boat such as slow down, stop or pull up.
And having a washdown system in place will allow you to bring up a clean anchor other than scooping dirt from the seafloor.
Globo Surf Overview
Anchoring a boat requires certain measures to make sure that the anchor doesn’t dislodge and the boat is where you need it to be. You will need to consider the type of anchor and the nature of the sea bed. It helps to have an extra anchor in case the first anchor gets tangled and lost.
With this guide on how to anchor a boat, you can enjoy your time out at sea, do fishing and even relax in your comfortable boat deck chair as you enjoy the warm sun knowing that your boat is secure.