How to Anchor a Boat

There’s more to anchoring a boat than simply tossing an anchor overboard. Knowing how to properly anchor a boat is an essential skill for any boater. Anchoring a boat can make all the difference in an emergency, when you’re fishing, or just having fun with family on the water. 

What We’ll Cover for How to Anchor a Boat

While in movies it often looks like something just hits a switch and the anchor drops, any long-time boater will tell you that’s not exactly a sound method and that’s not how anchors work. You need to walk through a few steps to anchor your boat, especially if you’re in unfamiliar waters. This is going to include:

• Pre-anchor considerations including anchor types
• Checking the depth 
• Identifying the seabed
• Checking for hazards
• Positioning your boat
• Preparing anchor and line/calculating scope
• Dropping the anchor safely
• Checking for drag and setting markers
• Resetting the anchor if needed
• Retrieving the anchor
• Night anchoring

In addition, we’ll also look at some tips for anchoring, including in tight spaces.

Basic Steps for Anchoring a Boat

In simple terms, the process of anchoring your boat should only take a few steps. We’ll give you the very basic rundown here and then address some of these steps in a little more detail further on. 

1. Check your depth with a chart or depth sounder and ensure you have enough rode (line) to drop anchor where you’re positioned.

2. Calculate your scope, which is the ratio of line to depth. You’ll want about 3:1 in calm waters and as much as 5:1 in rougher seas. Some boaters will go as high as 10:1 in high winds and somewhere in the middle if their mooring for the night.

3. Lower your anchor (don’t just toss it) and let out the scope you calculated slowly before securing your line to a bow cleat. 

4. Find a fixed and easy to track landmark on shore that you can use to check for drag. Your GPS can also help do this if a landmark isn’t an option. You’ll need to monitor this over the course of your time at anchor to see if you’re moving or not. You can pull the anchor up and reset if you find you haven’t set it properly and there is some drag.
   
5. When it’s time to retrieve the anchor, you’ll want to slowly power the boat towards where it’s anchored while pulling in the line. The anchor should pull free once you are directly above it. If it’s snagged, you can very gently maneuver the boat in a circle around the anchor to pull from the opposite direction and loosen it.

6. Check the condition of your line and your anchor, clean off anything that may have become caught or soiled it, and safely store it for next time. 

Pre-Anchor Considerations

There is a checklist of steps you can take before worrying about the actual process of anchoring your boat. These won’t take long and, in the case of choosing the actual type of anchor, will be pretty limited by what anchor you have available. That said, there are many types of anchors on the market, so at some point you need to choose which one you think will serve best. Some boaters will have a couple types of anchors on board, depending on the seabed they expect to find.

Anchor Types

Fluke Anchor: Sometimes called a Danforth anchor. This kind of anchor works best on a muddy bottom. They’re great in sand as well. These are not ideal for a rocky bottom, however. These are recommended for medium sized boats.

Plow Anchors: Ideal for rocky bottoms. It can also set well in a bottom with a lot of weeds. These are recommended for larger boats.

Mushroom Anchors: You’ll want to use a mushroom anchor on a loose, flat bottom. They don’t set the way other anchors do. Best used only for kayaks or canoes.

Claw Anchors: Set well in many rough and rocky surfaces. Coral and weeds are also ideal for these. 

Grapnel Anchors: These are typically best for smaller vessels. The grapnel will anchor to a rock and set incredibly strongly.

Most boaters are going to use either the fluke or the plow anchor. The others have their supporters but it is rare that you’ll find yourself in many instances when either a fluke or a plow does not get the job done for you. To determine the anchor that will work best for your boat your best bet is to defer to guidelines from the manufacturer, so you will have to comparison shop. 

Check the Weather

• This is a tip some boaters forget about before they head out. Not only is the weather important information for boating in general, it’s important for anchoring. Knowing if the seas are going to be rough will alter how much line you’ll be using. 
• It can also help you determine if it will be safe to anchor at all. If you don’t have enough line to scope for the conditions, dropping anchor is not advisable. This can prevent damage to your anchor, the rode, your boat and accidents that could harm you and your passengers.

Check Depth and Conditions

Charts and depth sounders are vital here. You need to calculate distance to the bottom to get an accurate read on how much line you’ll need. 

This is also good to determine the type of seabed you’re dealing with so you know if your anchor will work properly. If the bottom is covered in rocks, for instance, you know the fluke anchor may not be ideal and you’ll either need to use a different anchor if you can, or change location.

Finally, be aware of any hazards like debris, other vessels, sunken trash and so on.

Calculate Scope

The anchor line, or rode, needs to be calculated based on two things:

• Water depth
• Water conditions

There are many different recommendations from many different boats on how to calculate this. 

• The bare minimum you will see listed anywhere is 3:1 and this is for perfectly calm conditions like you might find on a small pond or lake.
• In this example, 3:1 refers to how many feet or line, or rode, you need compared to how many feet deep the water is. So three feet of line for every one foot of water. If you were fishing in a shallow, 5 foot deep pond, your scope would be three times that or 15 feet.
• On larger bodies of water with a stronger current, even in calm weather, a good minimum to use is 5:1. 
• However, it’s not unheard of for boaters to boost that as high as 7:1 in an effort to better handle shifting currents and potential winds. The deeper the water, the more beneficial it may be to calculate a higher ratio.
• If you plan to moor overnight it’s also a good idea to have a higher ratio. This is because you can’t fully monitor your conditions during sleeping hours so it’s safer to go with something like 8:1 or more.
• In rougher waters when the winds are higher or the current is stronger, ratios as high as 10:1 can be employed. Be aware of what your anchor and your boat are able to handle in conditions like these, however. If the seas are too rough, it’s best to not try to anchor at all if you don’t need to.

Setting Your Anchor

Once you have picked a spot you want to anchor, calculate your scope and consider the current or wind if there is any. Now it’s time to set the anchor.

• From the spot where you want to be, take your boat the length of your calculated scope from the spot into the wind or current if there is one. This is where you can let your anchor out.
• Drop the anchor slowly so the line doesn’t get bunched or tangled. The wind or current will start you drifting towards the spot you chose where you want your boat to be anchored. On calm seas you can throttle very slowly, letting out the line as you go.
• When you reach the limit of the scope the current should put pressure on the anchor and cause it to dig in or set. 
• If you continue to drift your anchor didn’t set and you may need to reverse, pull in your line slowly, and then try to set it again. 
• Once your anchor sets, secure the rode to a bow cleat.
• You can put your boat in reverse and apply a very small amount of throttle to give the anchor a little extra push to get it set firmly.

Watch for Drag

An anchor may sometimes seem set when it is not. The line will feel tight and secure and, at first glance, the boat will look moored in place. It is possible you may still be dragging in this situation. Drag occurs when the anchor has reached the seabed but is not firmly dug in. This can allow you to drift slowly out of position.

• Wind, current or tides can cause drag by making the boat swing over where your anchor is set, pulling it loose.
• You can monitor for drag by picking stationary landmarks on the shore. Find a spot like a building, an unusual tree or other landmark and line up your view of it from a specific spot on the boat. It’s easier if you can line up two landmarks so you can see your position in relation to both. If they no longer line up after a period of time, you know you’re drifting. 
• Electronics like GPS or a chartplotter can also show you if you’re dragging. You can rig a depth finder to sound an alarm when the depth changes too drastically as well. 
• If your anchor has come loose or was never set properly, reset to try again.

Retrieving the Anchor

When it comes time to pull your anchor back in, the process must be done carefully as well.

• Slowly throttle towards the anchor while pulling in the line as you go.
• Keep this up until the boat is directly over where the anchor is set.
• Most anchors are designed to pull free when the line is pulled up at close to a 90 degree angle, or straight up.Stop the boat once you are in position. If all went to plan, simply pulling the line directly above the anchor will easily allow you to pull it the rest of the way into the boat.
• If the anchor is still stuck somehow, keep the excess lined pulled up out of the water and maneuver around the anchor in a circle. This should cause the anchor to break free from whatever is holding it in place.

How to Anchor Overnight

The process of anchoring at night is almost the same as anchoring during the day, but does require some added considerations. Several things can affect a boat anchored overnight. These include:

• Winds and current
• Tides
• Traffic from other boats

You can’t control the winds and tides or predict traffic from other boats, but you can plan for it.

• Choose an overnight anchoring position not prone to strong winds and currents. You’ll want to pick a place shallow enough that scope is not an issue you’ll need to worry about.
• Speaking of, for overnight mooring, a ratio of at least 7:1 is needed but 10:1 is better.
• Make sure you have studied the tides in the area to be prepared for rising or lowering sea levels. You don’t want to be caught with too short of a line in a rising tide, or find yourself aground if the tide went out.
• Make sure you are not crowded. You need to consider your anchor point like the center of a compass. Your boat may drift all around that point at night in a full circle, the full length of your line, so you don’t want any obstacles or other boats in your way.
• Make sure you have ideal bottom conditions for your boat and anchor. If your anchor can’t set strongly you may drag and drift which could cause an accident.
• Set an all around light on the top of your vessel from sundown to sunrise to alert other boaters that you are at anchor

Anchoring in Wind or Tight Spaces

• Your best bet for avoiding wind changes is two anchors. You want to set the second anchor in a V-shape. If the wind starts to shift and the boat drags the anchor, the other is right there. Because they are at opposing angles, odds are one will always set even if the other does not.
• In extreme cases you can still up the ante. A third anchor can be used as well. The shape is the same, just use a V. In this case, one anchor goes out straight down the middle of the V. You would only use this method in serious weather. If you know a bad storm is coming and you are going to try to wait it out, the three anchor V can help keep you secure.
• So you want to set your V but there are other boats nearby? Now what? The tightness of your anchorage depends on how much room you have handy. If you have room to turn around and not hit anything at all, then the V we mentioned is fine. The angle can be anywhere from 140 degrees to 180 degrees. That 180 ensures you move less, but you’ll need a big anchor. Your boat can still move with the wind. The bow stays still because of the anchors, but the stern shifts in the wind. If you plan to sleep on your boat, this is a good way to do it. The motion is much less bothersome.
• If you don’t have room, you’ll need more security. You never want to risk hitting another boat. If you’re near other vessels or underwater hazards, another anchor can help you out. Use the V formation off the bow. But also employ another anchor off the stern of the boat. You can do this vice versa as well. Byt that we mean two stern anchors in a V and one at the bow. It depends on how the wind is blowing and what works best.
• This three anchor method prevents the boat from drifting around the anchors. Remember, with anchors in a V, your boat can spin around them in a full 360. With a stern anchor, you stay rooted in place. The downside here is that the motion on the boat is really felt. You’re fighting the current and the waves more noticeably. It can make for a rough night of sleep.

Anchoring Tips

We’ve covered all the basics here but there are a few things you may want to keep in mind.

• Make sure you know the best type of rode for your boat and anchor. Most boaters use chain and rope together. Chain adds weight to help set the anchor by keeping it at a lower angle but it will also prevent chafing which can happen to rope that might rub against rocks or coral on the bottom. 
• Between 6 and 8 feet of chain between the anchor and the rode is pretty standard.
• Research your anchor before buying. Is it designed to handle a boat of your size? Bigger doesn’t always mean better so get the right anchor for your boat and for where you intend to use it.
• Never rig your anchor line to the stern of the boat. You could end up pulling the stern so low that you swamp the vessel.
• Always be courteous of other boaters when mooring nearby. Keep in mind potential swing radius so you don’t cause any accidents when anchoring near others.
• If your anchor becomes stuck and you are unable to retrieve it after several tries, don’t be afraid to cut it loose. 
• If you have a windlass on your boat remember that it is not designed to hold the weight of your boat under anchor. You still need to use cleats to be safe and secure
• Keep your anchor and your road clean and dry when not in use. Store them out of the sun to maintain their lifespan.

The Bottom Line

It seems like a long process to learn how to anchor a boat but it’s a lot like riding a bike. Once you know what you’re doing it becomes second nature and happens naturally.

Always make sure you know the depth of the water and the seabed conditions to ensure you anchor properly. Monitoring your anchor is one of the most important parts so make sure you’re doing it safely. Even overnight, you’ll want to have someone periodically monitoring anchor conditions to look out for dragging.

The important things to remember are knowing your conditions, calculating your scope, setting the anchor and retrieving it safely. Once you have those done the process is often quick and painless.