Knowing how to use an anchor properly can broaden your boating horizons.
If you are new to boating, the “Boating Basics” series of videos from Mercury Marine provides an engaging, educational guide to our favorite pastime that will help you gain confidence on the water. Even if you are an experienced boater, you might pick up a few tips.
Anchoring is an easily acquired skill that every boater should attain. An anchor lets you “park” the boat safely and securely in places where there are no docks, like your local sandbar, a quiet cove or a fishing spot. An anchor also is an important part of your boat’s safety equipment. If you should lose power, you can use the anchor to keep your boat in one spot and prevent it from drifting into potential hazards until help arrives. You should never leave the dock without an anchor on board, and having two provides a nice backup.
To see the anchoring process in action, check out the videos below.
How to Select an Anchor and Rode
When you choose an anchor for your boat, the general rule is 1 pound of anchor per foot of boat. So, if you have a 25-foot boat, you should look for a 25-pound anchor and so forth.
There are many different anchor types, each designed to hold firmly to a different sort of seabed or freshwater bottom: sandy, muddy, rocky, etc. To select the right anchor for the bottom conditions in your local boating area, ask a licensed captain, your Mercury Authorized Dealer, a marina manager or a member of the local U.S. Coast Guard Auxiliary for a recommendation.
Once you have the anchor, you will need an anchor rode. This consists of a length of chain attached to the anchor and a length of nylon rope connected to the chain.
The general rule is 1 foot of chain for every foot of boat – for example, a 25-foot chain for a 25-foot boat. Attached to the chain, you should have at least 10 feet of line for every foot of depth in the waters where you plan to anchor.
Calculating Anchoring Scope
Before you set the anchor, you need to calculate the proper scope, which is the ratio of anchor rode to water depth. If there are strong winds or currents, you may need to use a scope of 10-to-1, or 10 feet of rode for each foot of water depth. In calm waters, a scope of 5-to-1 usually is sufficient. When calculating your scope, the water depth should include the distance from the water’s surface to the cleat where you’re tying off.
When the anchor grips the bottom firmly, it’s called “setting the anchor.” If it slips, letting out more rode and increasing the scope often will help to set the anchor. Mark your nylon anchor line with a dark marker or waterproof paint at 25-foot intervals so you can keep track of how much rode you have out.
How to Set the Anchor
When you are preparing to anchor, first determine the direction that the wind is blowing or the current is flowing in that area. This is called “reading the drift,” because it will tell you which way your boat is likely to drift when you shut off the engine. Pick the spot where you want to be, then head directly into the wind or current from there. Stop when you think you’ve gone far enough to account for the scope.
Ideally, another passenger in the bow should tend to the anchor while you position the boat. At the driver’s command, the person in the bow should lower the anchor overboard. Once it hits bottom, slowly back up while letting out the needed amount of rode to achieve the right scope, then tie off the line to a bow cleat. Some boats are equipped with a windlass, which is a winch used to raise and lower the anchor from the bow. If your boat has a winch, be sure to unlatch the safety cable before use.
The force of the wind or current and your rearward momentum should help to set the anchor in the bottom. Bumping the boat briefly into reverse can help this process. If you don’t end up where you planned to be at anchor, you can reposition by letting out or bringing in some of the rode. Then retie the line to the cleat. Don’t forget, you can always pull the anchor up and try again.
As a safety precaution, it’s a good idea to have a knife onboard in case the weather deteriorates quickly or an inattentive boater is bearing down and you need to cut the rode to stay out of harm’s way.
How to Retrieve the Anchor
At the end of your stay “on the hook,” you can retrieve your anchor simply by putting the boat into gear and giving it some throttle to release tension on the rode. The person in the bow should reel or pull in the line briskly as the boat moves forward. This will help to avoid getting the line tangled in your boat’s propeller.
When you see that the anchor line is vertical, tie it off to the bow cleat or release the button on the winch and use the boat’s forward momentum to free the anchor. If it doesn’t pull free right away, a couple more bumps on the throttle should help. If you are using a windlass, release the button just before the anchor reaches the boat. Tap the button a few times to gently bring the anchor in and snug it up.
Help stop the spread of AIS – It is a best boating practice to clean your anchor and rode thoroughly after every use, especially if you plan to cruise or trailer your boat to another body of water. If your anchor has picked up an aquatic invasive species from the bottom, this will prevent it from “hitching a ride” to another body of water where it should not be.
Plan for the boat to swing – Anytime you are anchoring at a sandbar or in a mooring field or anchorage where there are lots of other vessels, try to keep as much open space around your boat as possible. You don’t know how much scope other boats are using at anchor, and you don’t want to risk swinging into another boat if the wind, current or tide should change.
Use two anchors on the sandbar – When you anchor at a sandbar or a beach, bring along a second, smaller anchor. If there are other boats nearby, it’s best to set your main anchor while backing in. Then, when you are lined up to your anchoring spot, deploy your secondary anchor off the stern and cleat it off. This will keep you from accidentally drifting into other boats. Never use a stern anchor in rough conditions, though, as this can cause a dangerous situation.
Knowing how to use an anchor properly will keep your boat secure and give you peace of mind so you can concentrate on having fun whenever you are “hanging on the hook.”